Autoclaved aerated concrete block and preparation method thereof

Abstract

The invention relates to the technical field of building lightweight walls, and provides an autoclaved aerated concrete block and a preparation method thereof. The autoclaved aerated concrete block is prepared from, by weight, 55-60 parts of slurry, 25-30 parts of fly ash, 20-22 parts of lime, 20-25 parts of cement, 0.8-1 part of rubber powder, 0.05-0.07 part of aluminum powder and 2-4 parts of gypsum, the rubber powder is composed of first rubber powder and second rubber powder, and the glass transition temperature of the first rubber powder is different from that of the second rubber powder. According to the technical scheme, the problem of insufficient strength of autoclaved aerated concrete blocks in related technologies is solved.

Description

Technical Field

[0001] This invention relates to the field of lightweight building wall technology, specifically to an autoclaved aerated concrete block and its preparation method. Background Technology

[0002] Autoclaved aerated concrete (AAC) blocks are porous silicate blocks made primarily from siliceous and calcareous materials, with the addition of a foaming agent, through processes such as batching, mixing, pouring, pre-curing, cutting, and autoclaving. Their interior contains numerous uniformly distributed micropores, giving them excellent properties such as lightweight, thermal insulation, sound insulation, and fire resistance. Furthermore, the raw materials are widely available, and the production process consumes relatively little energy, making them a new type of wall material that aligns with the trends of energy-saving and green building materials.

[0003] However, as the construction industry's requirements for the comprehensive performance of wall materials continue to increase, the shortcomings of existing autoclaved aerated concrete (AAC) blocks in terms of strength have gradually become apparent. Insufficient strength in AAC blocks can lead to numerous problems. Firstly, during wall construction, insufficiently strong AAC blocks are prone to damage and chipping due to external forces during handling and installation, increasing material waste and affecting construction efficiency and wall surface flatness. Secondly, during use, walls constructed with insufficiently strong AAC blocks are susceptible to cracking and deformation due to their own weight, temperature changes, or even slight vibrations, reducing the wall's integrity and stability, and consequently affecting the building's lifespan.

[0004] Therefore, it is very necessary to develop a high-strength autoclaved aerated concrete block. Summary of the Invention

[0005] This invention proposes an autoclaved aerated concrete block and its preparation method, which solves the problem of insufficient strength of autoclaved aerated concrete blocks in related technologies.

[0006] The technical solution of the present invention is as follows: The present invention proposes an autoclaved aerated concrete block, comprising the following raw materials in parts by weight: 55-60 parts of slurry, 25-30 parts of fly ash, 20-22 parts of quicklime, 20-25 parts of cement, 0.8-1 parts of adhesive powder, 0.05-0.07 parts of aluminum powder, and 2-4 parts of gypsum. The adhesive powder is composed of a first adhesive powder and a second adhesive powder, wherein the first adhesive powder and the second adhesive powder have different glass transition temperatures.

[0007] As a further technical solution, the slurry is prepared by mixing fly ash and water in a mass ratio of 7:3.

[0008] As a further technical solution, the glass transition temperature of the first adhesive powder is 15°C, and the glass transition temperature of the second adhesive powder is -6°C.

[0009] In the autoclaved aerated concrete (AAC) blocks of this invention, the first adhesive powder has a glass transition temperature of 15°C, and the second adhesive powder has a glass transition temperature of -6°C. The adhesive powder with the lower glass transition temperature softens and flows more easily during preparation or curing, fully filling the internal pores of the block and encapsulating the raw material particles to form a dense bonding interface. The adhesive powder with the higher glass transition temperature provides rigid support, preventing the bonding layer from deforming under stress. The two work together to make the bonding between particles stronger, thereby improving the compressive strength of the AAC blocks.

[0010] As a further technical solution, the mass ratio of the first adhesive powder to the second adhesive powder is 1~1.2:1.

[0011] As a further technical solution, the aluminum powder is a composite aluminum powder, and the preparation method of the composite aluminum powder includes the following steps: dispersing 3-(trihydroxysilyl)propanesulfonic acid in anhydrous ethanol, adding aluminum powder, mixing and drying to obtain composite aluminum powder.

[0012] In this invention, aluminum powder is composite-treated with 3-(trihydroxysilyl)propanesulfonic acid in autoclaved aerated concrete (AAC) blocks. This improves the dispersibility of aluminum powder in the slurry, preventing uneven foaming caused by aluminum powder agglomeration. It promotes the formation of finer, more uniform bubbles with a reasonable pore size distribution, reduces large-diameter and interconnected pores, lowers stress concentration points under load, and improves the strength of the AAC blocks.

[0013] As a further technical solution, the mass ratio of 3-(trihydroxysilyl)propanesulfonic acid to aluminum powder is 4~5:50.

[0014] As a further technical solution, the mixing time is 2 to 4 hours, for example, it can be 2 hours, 2.5 hours, 3 hours, 3.5 hours, or 4 hours, preferably 3 hours.

[0015] As a further technical solution, the mass ratio of the aluminum powder to the anhydrous ethanol is 1:10~15, for example, it can be 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, preferably 1:10.

[0016] As a further technical solution, the mass ratio of 3-(trihydroxysilyl)propanesulfonic acid to aluminum powder is 4~5:50.

[0017] A method for preparing autoclaved aerated concrete (AAC) blocks, comprising the following steps: S1. Weigh the slurry, the fly ash, the quicklime and the gypsum, add water and stir to obtain a cementitious slurry; S2. Disperse aluminum powder in water to obtain a gas-generating agent solution; S3. Mix the cementitious slurry, the cement and the adhesive powder, stir for 8-10 minutes, then add the gas-generating agent solution and stir for 1-2 minutes to obtain the mixed slurry. S4. The mixed slurry is poured, shaped, cut, and autoclaved to obtain the autoclaved aerated concrete blocks.

[0018] As a further technical solution, in step S1, the water-cement ratio of the adhesive slurry is 0.6~0.7.

[0019] As a further technical solution, in step S2, the mass ratio of the aluminum powder to the water is 1:25~30, and the dispersion time is 3~4 minutes.

[0020] As a further technical solution, in step S3, the mixing temperature is 40~50℃.

[0021] As a further technical solution, the temperature of the autoclaving is 190~200℃, and the time of the autoclaving is 8~10h.

[0022] The working principle and beneficial effects of this invention are as follows: In this invention, the adhesive powder in autoclaved aerated concrete (AAC) blocks is composed of a first adhesive powder and a second adhesive powder with different glass transition temperatures. These two adhesive powders differ in temperature adaptability, flowability, rigidity, and flexibility. When mixed, their different temperature adaptability allows them to function effectively at different curing stages, reducing the formation of internal micro-cracks caused by temperature changes. The bonding system formed by the compound adhesive powder possesses both flexibility and rigidity, buffering external impacts and resisting environmental stresses during long-term use, effectively improving the strength of the AAC blocks. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] Unless otherwise specified, the following embodiments and comparative examples are as follows: Slurry: It is made of fly ash and water in a mass ratio of 7:3. The fly ash is Grade I fly ash with a particle size of 325 mesh. Fly ash: Grade I fly ash, with a particle size of 325 mesh; Lime: 100 mesh particle size; Cement: 45.2 ordinary Portland cement; First adhesive powder: redispersible latex powder of PVA / EVA blend, with a glass transition temperature of 15℃, model number WWJF-8040; Second adhesive powder: redispersible latex powder of PVA / EVA blend, with a glass transition temperature of -6℃, model number WWJF-8050; Aluminum powder: particle size 325 mesh; Gypsum: Particle size 120 mesh.

[0025] Example 1 A method for preparing autoclaved aerated concrete blocks includes the following steps: S1. Weigh 55 parts of slurry, 25 parts of fly ash, 20 parts of quicklime and 2 parts of gypsum, add water and stir to obtain a cementitious slurry with a water-cement ratio of 0.65. S2. Disperse 0.05 parts of aluminum powder in 1.5 parts of water to obtain a gas-generating agent solution; S3. Mix the cementitious grout, 20 parts of cement and 0.8 parts of adhesive powder at 40℃, stir for 8 minutes, then add the gas-generating agent solution and stir for 1 minute to obtain the mixed grout. S4. After the mixed slurry is poured and shaped, the blank is cut, and it is autoclaved at 190℃ for 10 hours, autoclaved aerated concrete blocks are obtained. The adhesive powder consists of a first adhesive powder and a second adhesive powder in a mass ratio of 1:1.

[0026] Example 2 A method for preparing autoclaved aerated concrete blocks includes the following steps: S1. Weigh 58 parts of slurry, 28 parts of fly ash, 21 parts of quicklime and 3 parts of gypsum, add water and stir to obtain a cementitious slurry with a water-cement ratio of 0.65. S2. Disperse 0.06 parts of aluminum powder in 1.8 parts of water to obtain a gas-generating agent solution; S3. Mix the cementitious grout, 22 parts of cement and 0.9 parts of adhesive powder at 45℃, stir for 9 minutes, then add the foaming agent solution and stir for 1.5 minutes to obtain the mixed grout. S4. After the mixed slurry is poured and shaped, the blank is cut, and it is autoclaved at 195℃ for 9 hours, autoclaved aerated concrete blocks are obtained. The adhesive powder consists of a first adhesive powder and a second adhesive powder in a mass ratio of 1:1.

[0027] Example 3 A method for preparing autoclaved aerated concrete blocks includes the following steps: S1. Weigh 60 parts of slurry, 30 parts of fly ash, 22 parts of quicklime and 4 parts of gypsum, add water and stir to obtain a cementitious slurry with a water-cement ratio of 0.65. S2. Disperse 0.07 parts of aluminum powder in 2.1 parts of water to obtain a gas-generating agent solution; S3. Mix the cementitious grout, 25 parts of cement and 1 part of adhesive powder at 50℃, stir for 10 minutes, then add the foaming agent solution and stir for 2 minutes to obtain the mixed grout. S4. After the mixed slurry is poured and shaped, the blank is cut, and it is autoclaved at 200℃ for 8 hours, autoclaved aerated concrete blocks are obtained. The adhesive powder consists of a first adhesive powder and a second adhesive powder in a mass ratio of 1:1.

[0028] Example 4 The difference between Example 4 and Example 2 is that the adhesive powder is composed of a first adhesive powder and a second adhesive powder in a mass ratio of 1.2:1.

[0029] Example 5 Compared with Example 4, Example 5 differs in that the first adhesive powder (a redispersible latex powder of Pva / Eva blend, with a glass transition temperature of 15°C and model number WWJF-8040) is replaced with an equal amount of adhesive powder, a redispersible latex powder of Pva / Eva blend, with a glass transition temperature of 10°C and model number WWJF-8010.

[0030] Example 6 The preparation method of composite aluminum powder includes the following steps: 4 parts of 3-(trihydroxysilyl)propanesulfonic acid are dispersed in 500 parts of anhydrous ethanol, 50 parts of aluminum powder are added, and the mixture is dried after 3 hours to obtain composite aluminum powder. Compared with Example 4, the aluminum powder was replaced with an equal amount of composite aluminum powder prepared by the above preparation method.

[0031] Example 7 The difference between Example 6 and Example 7 is that the amount of 3-(trihydroxysilyl)propanesulfonic acid added is 5 parts.

[0032] Example 8 Compared with Example 7, Example 8 differs in that 3-(trihydroxysilyl)propanesulfonic acid is replaced with an equal amount of 3-aminopropyltriethoxysilane, and anhydrous ethanol is replaced with an equal amount of mixed solution, which consists of ethanol and water in a mass ratio of 3:1.

[0033] Comparative Example 1 The difference between Comparative Example 1 and Example 2 is that the adhesive powder is a first adhesive powder.

[0034] Comparative Example 2 The difference between Comparative Example 2 and Example 2 is that the adhesive powder is a second type of adhesive powder.

[0035] Experimental Example 1 The compressive strength of the autoclaved aerated concrete blocks prepared in Examples 1-8 and Comparative Examples 1-2 was tested according to the test methods specified in GB / T 11969-2020 "Test Methods for Performance of Autoclaved Aerated Concrete".

[0036] The test results are shown in Table 1: Table 1 Performance test results of Examples 1-8 and Comparative Examples 1-2

[0037] Table 1 shows that when the adhesive powder is composed of first and second adhesive powders with different glass transition temperatures, the strength of autoclaved aerated concrete (AAC) blocks can be improved. When composite aluminum powder treated with 3-(trihydroxysilyl)propanesulfonic acid is added, the strength of the resulting AAC blocks is even better.

[0038] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An autoclaved aerated concrete block, characterized in that, The raw materials include the following components by weight: 55-60 parts slurry, 25-30 parts fly ash, 20-22 parts quicklime, 20-25 parts cement, 0.8-1 parts adhesive powder, 0.05-0.07 parts aluminum powder, and 2-4 parts gypsum. The adhesive powder is composed of a first adhesive powder and a second adhesive powder, and the first adhesive powder and the second adhesive powder have different glass transition temperatures.

2. The autoclaved aerated concrete block according to claim 1, characterized in that, The glass transition temperature of the first adhesive powder is 15°C, and the glass transition temperature of the second adhesive powder is -6°C.

3. The autoclaved aerated concrete block according to claim 1, characterized in that, The mass ratio of the first adhesive powder to the second adhesive powder is 1~1.2:

1.

4. The autoclaved aerated concrete block according to claim 1, characterized in that, The aluminum powder is a composite aluminum powder, and the preparation method of the composite aluminum powder includes the following steps: dispersing 3-(trihydroxysilyl)propanesulfonic acid in anhydrous ethanol, adding aluminum powder, mixing and drying to obtain composite aluminum powder.

5. The autoclaved aerated concrete block according to claim 4, characterized in that, The mass ratio of 3-(trihydroxysilyl)propanesulfonic acid to aluminum powder is 4~5:

50.

6. A method for preparing autoclaved aerated concrete (AAC) blocks, used to prepare the autoclaved aerated concrete (AAC) blocks according to any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Weigh the slurry, the fly ash, the quicklime and the gypsum, add water and stir to obtain a cementitious slurry; S2. Disperse aluminum powder in water to obtain a gas-generating agent solution; S3. Mix the cementitious slurry, the cement and the adhesive powder, stir for 8-10 minutes, add the gas-generating agent solution, and stir for 1-2 minutes to obtain the mixed slurry; S4. The mixed slurry is poured, shaped, cut, and autoclaved to obtain the autoclaved aerated concrete blocks.

7. The method for preparing autoclaved aerated concrete blocks according to claim 6, characterized in that, In step S1, the water-cement ratio of the cementitious slurry is 0.6 to 0.

7.

8. A method for preparing autoclaved aerated concrete blocks according to any one of claims 6, characterized in that, In step S2, the mass ratio of the aluminum powder to the water is 1:25~30, and the dispersion time is 3~4 minutes.

9. The method for preparing autoclaved aerated concrete blocks according to claim 6, characterized in that, In step S3, the mixing temperature is 40~50℃.

10. A method for preparing autoclaved aerated concrete blocks according to claim 6, characterized in that, The temperature for autoclaving is 190~200℃, and the time for autoclaving is 8~10h.

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