High-strength carbon sequestration aerated concrete and preparation method thereof

Abstract

The invention belongs to the technical field of building materials, and discloses high-strength carbon sequestration aerated concrete which is prepared from, by weight, 43-54 parts of cement, 10-17 parts of sand, 2-5 parts of quicklime, 0.08-0.2 part of aluminum powder paste, 28-33 parts of water, 3-5 parts of catalyst and 1-2 parts of fumed silica shaped phase change material, and the cement is Portland cement with the strength grade of 52.5. The invention also discloses a preparation method of the aerated concrete, and the preparation method comprises the following steps: stirring the raw materials, introducing CO2 gas during stirring, then adding the aluminum powder paste suspension liquid, continuously stirring, performing injection molding, and soaking in water for curing. The prepared aerated concrete has good mechanical properties, autoclaved curing is not adopted in the preparation method, the production cost is reduced, the aerated concrete is more environmentally friendly, and meanwhile the production efficiency is greatly improved compared with a traditional autoclaved curing-free process.

Description

Technical Field

[0001] The present invention belongs to the technical field of building materials, and in particular relates to high-strength carbon-fixing aerated concrete and a preparation method thereof. Background Art

[0002] Aerated concrete is a lightweight, porous building material based on siliceous and calcareous materials, incorporating aluminum powder as a gas-forming agent. It is steam-cured at high temperature and high pressure to form a porous structure. It boasts lightweight, high strength, thermal insulation, fire resistance, and sound insulation. Furthermore, the production process recycles industrial waste, meeting environmental requirements. Products include blocks, wall panels, and insulation boards, and are widely used in high-rise buildings, earthquake-resistant structures, cold regions, and soft foundation projects. They can significantly reduce building weight and improve energy efficiency. Although not suitable for humid, high-temperature, or highly corrosive environments, their ease of construction and low carbon footprint align with the needs of green building development.

[0003] Curing is a critical step in the preparation of aerated concrete. By providing a suitable curing environment, it effectively promotes the development of concrete's mechanical properties. Currently, the industry primarily utilizes two methods: autoclaving and non-autoclaving. While autoclaving can ensure product strength, it suffers from high energy consumption and poor environmental performance. Traditional non-autoclaving, on the other hand, suffers from the limitation of relatively low product strength. Against this backdrop, ensuring that aerated concrete meets mechanical performance standards while further reducing energy consumption has become a key area of ​​technological innovation in the industry. Summary of the Invention

[0004] The object of the present invention is to overcome at least one of the shortcomings of the prior art and provide a high-strength carbon-fixing aerated concrete and a preparation method thereof. The aerated concrete has good mechanical properties and does not use autoclaving in the preparation method, thereby reducing production costs and being more environmentally friendly.

[0005] The technical solution adopted by the present invention is:

[0006] On one hand, the present invention provides a high-strength carbon-fixing aerated concrete, which comprises, by weight, 43-54 parts of cement, 10-17 parts of sand, 2-5 parts of quicklime, 0.08-0.2 parts of aluminum paste, 28-33 parts of water, 3-5 parts of catalyst, and 1-2 parts of fumed silica shaped phase change material, wherein the cement is silicate cement with a strength grade of 52.5.

[0007] The above-mentioned aerated concrete raw material ratio used in this embodiment can achieve excellent mechanical properties, carbon fixation, and thermal conductivity. The addition of a catalyst can further enhance the mechanical properties of aerated concrete while also accelerating the mineralization and curing process, shortening the curing cycle. The addition of fumed silica-shaped phase change material can utilize the phase change material's high energy storage density and specific heat capacity to improve the thermal conductivity and energy efficiency of aerated concrete.

[0008] In some feasible embodiments, the catalyst includes a liquid catalyst and a powder catalyst, the liquid catalyst includes maleic acid, hydrogen peroxide, sodium hydroxide and distilled water, and the powder catalyst includes calcium carbonate, calcium silicate and calcium hydroxide.

[0009] The main component of the powder catalyst used in this embodiment, calcium carbonate, can regulate the crystallization behavior of the precipitation in the aerated concrete and induce calcium silicate (C3S and C2S) in the silicate concrete to participate in the reaction. At the same time, the calcium silicate in the powder catalyst can not only react with CO2, but also increase the mineralization rate and amount of silicate concrete. The silicate doping as a dispersant strengthens the internal diffusion of CO2 gas, especially the gas permeability in the early stage of the reaction. At the same time, the Ca in the powder catalyst can also react with CO2 and increase the mineralization rate and amount of silicate concrete. 2+ The ions have a very high binding capacity and can form complexes with liquid catalysts, which can quickly migrate in the pores and cracks in the concrete. The calcium complexes react with CO3 in the pores and cracks. 2- A reaction occurs to generate CaCO3 crystal precipitation, which further optimizes the pore structure of the concrete, promotes the mineralization reaction, and further improves the mechanical strength of the aerated concrete.

[0010] In some feasible embodiments, the weight ratio of the powder catalyst to the liquid catalyst is (15-20):1, preferably 20:1.

[0011] In some feasible embodiments, the powder catalyst is composed of calcium carbonate, calcium silicate and calcium hydroxide in a weight ratio of (2-4):(2-4):(1-2), preferably 2:2:1.

[0012] In some feasible embodiments, the particle size of the calcium carbonate particles in the powder catalyst is ≤20 μm. Powders with a particle size of ≤20 μm have a larger specific surface area, more surface active sites, and are more likely to adsorb Ca in the solution. 2+ and CO32-, promoting the formation of crystal nuclei while avoiding particles that are too large (such as >20μm) that may cause local uneven concentration or self-agglomeration to form secondary particles, which in turn hinders the uniformity of crystallization.

[0013] In some feasible embodiments, the method for preparing the liquid catalyst comprises the following steps:

[0014] Prepare a sodium hydroxide solution with a concentration of 0.15 mol / L for later use;

[0015] Mix maleic acid and distilled water, heat in a 70°C water bath and stir until completely dissolved;

[0016] A 30% by mass hydrogen peroxide solution is taken, and the sodium hydroxide solution and the hydrogen peroxide solution are added to the mixed solution of maleic acid and distilled water and stirred, wherein the mass ratio of the sodium hydroxide solution, the hydrogen peroxide solution, the maleic acid, and the distilled water is 3:1:3:3, to obtain the liquid catalyst.

[0017] In some feasible embodiments, the fumed silica-shaped phase change material is hexadecanol decanoate and / or polyethylene glycol.

[0018] In some feasible implementations, the fumed silica shaped phase change material is encapsulated in microcapsules. The microcapsule encapsulation method can prevent leakage of the phase change energy storage material, thereby improving compatibility with concrete.

[0019] On the other hand, the present invention also provides a method for preparing the above-mentioned high-strength carbon-fixing aerated concrete, the method comprising the following steps:

[0020] S1 Weigh the raw materials according to the test ratio, store the aluminum powder paste separately and prepare it into a suspension, and put the remaining raw materials into a closed mixer and stir for 2-4 minutes;

[0021] After S2 is stirred evenly, CO2 gas is introduced into the mixer, and the mixer is kept running for 60-120 seconds, and then the aluminum powder suspension is added and the stirring is continued;

[0022] S3: Pour the slurry into the test mold, with the pouring height not less than two-thirds of the test mold height. After standing, demould the mold and cut off the upper bread head of the test block at the same time.

[0023] S4: Completely immerse the test block in the curing box for water curing.

[0024] In this embodiment, CO2 gas is added during the raw material mixing process, so that the CO2 gas undergoes a mineralization reaction with the alkaline components in the concrete, achieving microcrystallization at an earlier stage. Compared with the traditional carbon dioxide mineralization curing process in which CO2 gas is added for mineralization reaction after the pouring stage is completed, the mechanical properties of aerated concrete can be further improved.

[0025] In some feasible embodiments, the amount of CO2 introduced in step S2 is 0.15-0.25 parts by weight. By adjusting the above CO2 gas incorporation parameters, the mechanical properties of aerated concrete can be further improved.

[0026] In some feasible implementations, in step S2, the aluminum powder paste suspension is added and stirred for 30-50 seconds.

[0027] In some feasible implementations, in step S3, the pouring temperature is 45-50° C., and the standing time is 2-4 hours.

[0028] In some feasible implementations, in step S4, the curing period is 28 days. DETAILED DESCRIPTION

[0029] By reference to the following detailed description, examples, it is possible to more easily understand the embodiments of the present invention. However, the materials and methods described herein are not limited to the specific embodiments presented in the detailed description, examples. It should be appreciated that the exemplary embodiments herein are merely illustrations of the principles of the present invention. Without departing from the spirit and scope of the present invention, many modifications and adjustments will be apparent to those skilled in the art.

[0030] In the description of this embodiment, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and is not to be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0031] In describing this embodiment, it should be noted that all ranges disclosed herein are to be understood to encompass any and all subranges subsumed therein. For example, the stated range "3% to 20%" should be considered to include any and all subranges beginning with a minimum of 3% or greater and ending with a maximum of 20% or less, such as 4% to 19%, or 4.5% to 15%, or 12% to 13%. Furthermore, all ranges disclosed herein are also considered to include the endpoints of the ranges, unless expressly stated otherwise. For example, the ranges "between 4 and 6," "4 to 6," or "4-6" should generally be considered to include the endpoints 4 and 6.

[0032] In the description of this embodiment, unless otherwise explicitly defined, terms such as "set," "install," and "connect" should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in this embodiment in conjunction with the specific content of the technical solution. The technical solution of the present invention is further described below with reference to exemplary embodiments.

[0033] To date, the building materials industry's total carbon emissions are approximately 3 billion to 3.5 billion tons of CO2, accounting for 11% to 12% of global carbon emissions. To address climate change, the building materials industry needs to accelerate technological innovation and green transformation. The existing technologies currently used in the cement products industry have exposed numerous flaws and shortcomings in practical application. As the world's leading producer and consumer of cement, my country's cement products industry poses significant carbon emission risks. Furthermore, aerated concrete currently primarily utilizes energy-intensive autoclave curing, which not only drives up production costs but also places a heavy burden on the environment. Furthermore, when autoclaved aerated concrete blocks are used in load-bearing structures, they must achieve a compressive strength of 5.0 MPa or higher, as required by JGJ / T 17-2020, the "Technical Standard for the Application of Autoclaved Aerated Concrete Products." This ensures stability and reliability in load-bearing applications. In terms of solid waste utilization, due to the strict standards set for solid waste selection and the constraints of transportation distance factors, the market share and production scale of cement-solid waste composite-based aerated concrete products are relatively limited, making it difficult to form economies of scale, further restricting the green and efficient development of the industry.

[0034] In order to solve the above problems, this embodiment provides a high-strength carbon-fixing aerated concrete, which includes, by weight: 43-54 parts of cement, 10-17 parts of sand, 2-5 parts of quicklime, 0.08-0.2 parts of aluminum paste, 28-33 parts of water, 3-5 parts of catalyst, and 1-2 parts of fumed silica shaped phase change material, wherein the cement is silicate cement with a strength grade of 52.5.

[0035] In this field, silicate cement with a strength grade of 52.5 is generally also represented by P.O52.5.

[0036] In some embodiments, the cement is 45-50 parts, the sand is 6-11 parts, the quicklime is 4-5 parts, the aluminum paste is 0.1-0.2 parts, the water is 28-30 parts, the catalyst is 4-5 parts, and the fumed silica shaped phase change material is 1-2 parts.

[0037] In some embodiments, the cement is 50 parts, the sand is 11 parts, the quicklime is 5 parts, the aluminum paste is 0.1 parts, the water is 28 parts, the catalyst is 4 parts, and the fumed silica shaped phase change material is 2 parts.

[0038] In one embodiment, the catalyst comprises a liquid catalyst and a powder catalyst. The liquid catalyst comprises maleic acid, hydrogen peroxide, sodium hydroxide, and distilled water, and the powder catalyst comprises calcium carbonate, calcium silicate, and calcium hydroxide. The weight ratio of the powder catalyst to the liquid catalyst is (15-20):1, preferably 20:1.

[0039] In one embodiment, the powder catalyst is composed of calcium carbonate, calcium silicate, and calcium hydroxide in a weight ratio of (2-4):(2-4):(1-2), preferably 2:2:1. In one embodiment, the particle size of the calcium carbonate particles in the powder catalyst is ≤20 μm. Preferably, the particle size of the calcium carbonate particles satisfies the following conditions: 5 μm ≤ particle size ≤15 μm.

[0040] In one embodiment, the preparation method of the liquid catalyst comprises the following steps:

[0041] Prepare a sodium hydroxide solution with a concentration of 0.15 mol / L for later use;

[0042] Mix maleic acid and distilled water, heat in a 70°C water bath and stir until completely dissolved;

[0043] A 30% by mass hydrogen peroxide solution is taken, and the sodium hydroxide solution and the hydrogen peroxide solution are added to the mixed solution of maleic acid and distilled water in proportion and stirred, wherein the mass ratio of the sodium hydroxide solution, the hydrogen peroxide solution, the maleic acid, and the distilled water is 3:1:3:3, to obtain the liquid catalyst.

[0044] In the present application, the preparation of a sodium hydroxide solution with a concentration of 0.15 mol / L can generally be carried out by conventional means in the art, and a hydrogen peroxide solution with a mass fraction of 30% is generally commercially available.

[0045] In one embodiment, the fumed silica-setting phase change material is hexadecanol decanoate and / or polyethylene glycol.

[0046] In the present application, when the fumed silica shaping phase change material is decanoic acid-hexadecanol, decanoic acid (CA) and hexadecanol (HA) are mixed in a mass ratio of 3:1, heated and stirred in a 60-80°C water bath until completely melted and a uniform liquid is formed, and then porous fumed silica is added as a shaping carrier. The molten mixture is mechanically stirred to fully fill the silica pores. The ratio of the uniform liquid to the fumed silica is 3:1 to 5:1, and after cooling, a solid-fixed shaping composite material is formed.

[0047] The fumed silica shaped phase change material is polyethylene glycol, which is obtained by heating polyethylene glycol to a molten state (70-80° C.) and then mixing it with fumed silica at a mass ratio of 3:1 to 4:1, and then mechanically stirring the molten polyethylene glycol to fully penetrate the carrier pores.

[0048] In one embodiment, the fumed silica shaped phase change material is encapsulated in microcapsules.

[0049] This embodiment also provides a method for preparing the above-mentioned high-strength carbon-fixing aerated concrete, the method comprising the following steps:

[0050] S1. Weigh the raw materials according to the test ratio, store the aluminum powder paste separately and prepare it into a suspension, and put the remaining raw materials into a closed mixer and stir for 2-4 minutes;

[0051] S2. Introduce CO2 gas into the mixer, keep the mixer running for 60-120 seconds, then add the aluminum powder suspension and continue stirring;

[0052] S3. Pour the slurry into the test mold to a height of two-thirds of the test mold height. Let it stand for a while before demoulding. At the same time, cut off the upper bread head of the test block.

[0053] S4. Completely immerse the test block in the curing box for water curing.

[0054] In some embodiments, the amount of CO2 introduced in step S2 is 0.15-0.25 parts by weight.

[0055] In some embodiments, in step S2, the aluminum powder paste suspension is added and stirred for 30-50 seconds.

[0056] In some embodiments, in step S3, the pouring temperature is 45-50° C., and the standing time is 2-4 hours.

[0057] In some embodiments, in step S4, the curing period is 28 days.

[0058] The raw materials used in the examples and comparative examples of this application are all commercially available. Among them, the manufacturer of silicate cement with a strength grade of 52.5 is Jidong Cement, and the manufacturer of calcium carbonate powder with a particle size of 15-20 μm is Yuen Technology.

[0059] The present application is further explained below with reference to the embodiments.

[0060] Example 1

[0061] This embodiment provides a high-strength carbon-fixing aerated concrete, which is composed of the following components in parts by weight: 50 parts of P.O52.5 cement, 11 parts of sand, 5 parts of quicklime, 0.1 parts of aluminum paste, 28 parts of water, 4 parts of catalyst, 1 part of polyethylene glycol, and 1 part of hexadecanol decanoate. The catalyst comprises a liquid catalyst consisting of maleic acid, hydrogen peroxide, sodium hydroxide and distilled water, and a powder catalyst consisting of calcium carbonate, calcium silicate and calcium hydroxide with a particle size of 10 μm in a weight ratio of 2:2:1, and the weight ratio of the liquid catalyst to the powder catalyst is 1:20. The preparation method of the liquid catalyst comprises the following steps: weighing sodium hydroxide powder to prepare a solution with a concentration of 0.15 mol / L for standby use, then weighing maleic acid and distilled water, mixing the two, placing them in a water bath heating environment and stirring, and when they are completely dissolved, weighing a hydrogen peroxide solution with a mass fraction of 30%, adding the sodium hydroxide solution and the hydrogen peroxide solution in proportion and stirring, the mass ratio of the sodium hydroxide solution, hydrogen peroxide solution, maleic acid and distilled water is 3:1:3:3, to obtain the liquid catalyst.

[0062] The preparation process of the above-mentioned high-strength carbon-fixing aerated concrete is as follows:

[0063] (1) Weigh the raw materials according to the experimental ratio, among which the aluminum powder paste is stored separately and prepared into a suspension, and the remaining raw materials are put into a closed mixer and stirred;

[0064] (2) After stirring evenly, 0.25 parts of 99% CO2 gas was introduced into the mixer, and the mixer was kept running for 100 seconds. Then, the aluminum powder suspension was added and stirring was continued for 30 seconds.

[0065] (3) Pour the slurry into the test mold, the pouring height is two-thirds of the test mold height, the pouring temperature is 50℃, and after standing for 2 hours, demould and remove the upper bread head of the test block;

[0066] (4) The test block is completely immersed in a curing box for water curing, and the curing period is 28 days.

[0067] Example 2

[0068] This embodiment provides a high-strength carbon-fixing aerated concrete, which is different from Example 1 in that the high-strength carbon-fixing aerated concrete of this embodiment is composed of the following components in parts by weight: 50 parts of P.O52.5 cement, 11 parts of sand, 5 parts of quicklime, 0.1 part of aluminum powder paste, 28 parts of water, 4 parts of catalyst, and 2 parts of decanoic acid-hexadecanol.

[0069] Example 3

[0070] This embodiment provides a high-strength carbon-fixing aerated concrete, which is different from Example 1 in that the high-strength carbon-fixing aerated concrete provided in this embodiment is composed of the following components in parts by weight: 50 parts of P.O52.5 cement, 11 parts of sand, 5 parts of quicklime, 0.1 part of aluminum powder paste, 28 parts of water, 4 parts of catalyst, and 2 parts of polyethylene glycol.

[0071] Example 4

[0072] This embodiment provides a high-strength carbon-fixing aerated concrete, which differs from Example 1 in that the high-strength carbon-fixing aerated concrete provided in this embodiment is composed of the following components in parts by weight: 50 parts of cement, 12 parts of sand, 5 parts of quicklime, 0.1 part of aluminum paste, 28 parts of water, 3 parts of catalyst, 1 part of polyethylene glycol, and 1 part of hexadecanol decanoate.

[0073] Example 5

[0074] This embodiment provides a high-strength carbon-fixing aerated concrete, which is different from Example 1 in that the high-strength carbon-fixing aerated concrete provided in this embodiment is composed of the following components in parts by weight: 45 parts of P.O52.5 cement, 11 parts of sand, 5 parts of quicklime, 0.08 parts of aluminum powder paste, 33 parts of water, 4 parts of catalyst, 1 part of polyethylene glycol, and 1 part of hexadecanol decanoate.

[0075] During the preparation process, 0.23 parts of 99% CO2 gas was introduced and stirred for 100 seconds.

[0076] Comparative Example 1

[0077] The difference from Example 1 is that this comparative example provides a high-strength carbon-fixing aerated concrete, which is composed of the following components in parts by weight: 50 parts of P.O52.5 cement, 17 parts of sand, 5 parts of quicklime, 0.1 parts of aluminum powder paste, and 28 parts of water.

[0078] Comparative Example 2

[0079] The difference from Example 1 is that this comparative example provides a high-strength carbon-fixing aerated concrete, which is composed of the following components in parts by weight: 50 parts of P.O52.5 cement, 11 parts of sand, 5 parts of quicklime, 0.1 parts of aluminum paste, 28 parts of water, 4 parts of catalyst, 1 part of polyethylene glycol, and 1 part of hexadecanol decanoate.

[0080] The above preparation process is as follows:

[0081] (1) Weigh the raw materials according to the test ratio and put them into a closed mixer and stir for 2 minutes;

[0082] (2) Pour the slurry into the test mold, the pouring height is two-thirds of the test mold height, the pouring temperature is 50℃, and after standing for 2 hours, demould and remove the upper bread head of the test block at the same time;

[0083] (4) The test block is completely immersed in a curing box for water curing, and the curing period is 28 days.

[0084] Comparative Example 3

[0085] The difference between this comparative example and Example 1 is that during the preparation process, 0.5 parts of 99% CO2 gas was introduced and stirred for 60 seconds.

[0086] Comparative Example 4

[0087] The difference between this comparative example and Example 1 is that during the preparation process, 0.3 parts of 99% CO2 gas was introduced and stirred for 100 seconds.

[0088] Comparative Example 5

[0089] The difference from Example 1 is that this embodiment provides a high-strength carbon-fixing aerated concrete, which is composed of the following components in parts by weight: 50 parts of P.O52.5 cement, 12 parts of sand, 5 parts of quicklime, 0.1 parts of aluminum powder paste, 29 parts of water, and 4 parts of catalyst.

[0090] The parameter comparison of the above embodiment and comparative example is shown in Table 1.

[0091] Table 1

[0092]

[0093]

[0094] The compressive strength, carbon fixation rate, dry density and thermal conductivity of the aerated concrete obtained in the above examples and comparative examples were tested, and the results are shown in Table 2 below:

[0095] Table 2

[0096]

[0097] Detection method

[0098] Compressive strength test method: According to the test requirements of GB / T11969-2020 "Autoclaved Aerated Concrete Performance Test Method", before the test, remove particles and debris between the compressive surface of the specimen and the pressure plate. The two sections of the specimen are the compressive surfaces. The pressure position should be aligned with the center of the pressure plate and the bottom plate. Load at a relatively appropriate speed until the specimen fails. Record the failure load and the size of the compressive surface of the specimen at this time. The compressive strength f of the specimen is calculated according to the following formula, accurate to 0.01MPa:

[0099]

[0100] Where, f: compressive strength of the specimen, in megapascals, MPa;

[0101] P: maximum breaking load, in Newton, N;

[0102] S: pressure surface area, in square millimeters, mm 2

[0103] The specimen size is a standard cube measuring 100mm x 100mm x 100mm. Samples for different operating conditions must be representative and universal, with no fewer than three samples tested under the same operating condition. After the strength test, samples must be retained for subsequent inspection and characterization.

[0104] Dry density test method: According to the test requirements of GB / T11969-2020 "Test method for properties of autoclaved aerated concrete", the dry density of the specimen is measured and calculated according to the following steps.

[0105] (1) Take a set of specimens and measure the axial dimensions of length, width, and height to the nearest 0.1 mm. Calculate the volume of the specimens, denoted by V. Then weigh the mass of the specimens, denoted by M, to the nearest 1 g.

[0106] (2) Place the specimen in an electric blast drying oven and keep it at (60±5)℃ for 24h, then at (80±5)℃ for 24h, and then dry it at (105±5)℃ until it reaches constant mass, which is represented by M0. Constant mass means that the difference in mass between the two drying times does not exceed 2g at an interval of 4h.

[0107] (3) Calculate the dry density of the specimen:

[0108]

[0109] Where:

[0110] r0—dry density, unit is kg / m 3；

[0111] M0—mass of the specimen after drying, in g;

[0112] V—specimen volume, in mm 3 .

[0113] Carbon fixation rate test method: The carbon fixation rate is calculated using the mass method. The mineralized test block and the unmineralized test block are dried and their masses are compared.

[0114]

[0115] where m before is the drying mass of the unmineralized test block m after The drying mass of the mineralized test block, the mass after mineralization and the mass of the unmineralized test block are all taken as the average value of three test blocks.

[0116] In summary, the calculation formula for carbon fixation rate is:

[0117]

[0118] Thermal conductivity test method: Remove a 40mm x 40mm x 40mm cubic specimen from the water-cured test and dry it at 105°C until constant weight. Use a 5501 probe, place it between two sample surfaces, and secure it to the test stand within the sample compartment. Before testing, adjust the sample and probe temperatures to the same. For hard, bulky materials, clamp the probe tightly to ensure close contact between the two sample surfaces. Perform thermal conductivity testing using a thermal conductivity meter.

[0119] By comparing the relevant test results of the aerated concrete of the embodiment and the comparative example, it can be seen that the relevant parameters of the catalyst, phase change energy storage material and CO2 gas have a significant impact on the mechanical strength, carbon fixation rate and thermal conductivity of the aerated concrete.

[0120] Specifically, by comparing Example 1 and Comparative Example 1, it can be seen that the addition of a liquid catalyst composed of maleic acid, hydrogen peroxide, sodium hydroxide and distilled water, and a powder catalyst composed of calcium carbonate, calcium silicate and calcium hydroxide in a weight ratio of 2:2:1 significantly improves the compressive strength of aerated concrete.

[0121] By comparing Example 1 and Comparative Example 5, it can be seen that the addition of phase change energy storage material can effectively reduce the thermal conductivity of aerated concrete, thereby achieving the energy storage effect of aerated concrete.

[0122] By comparing Examples 1-5 and Comparative Examples 2-4, it can be seen that whether CO2 gas is introduced, the amount introduced, and the stirring time after addition, especially the amount introduced, have a significant impact on the mechanical properties and carbon fixation rate of aerated concrete.

[0123] The above is a further detailed description of the present invention and should not be considered as a limitation on the specific implementation of the present invention. For those skilled in the art, simple deductions or substitutions that do not depart from the concept of the present invention are within the scope of protection of the present invention.

Claims

1. A high-strength carbon-fixing aerated concrete, characterized in that: The aerated concrete comprises, by weight, 43-54 parts of cement, 10-17 parts of sand, 2-5 parts of quicklime, 0.08-0.2 parts of aluminum paste, 28-33 parts of water, 3-5 parts of catalyst, and 1-2 parts of fumed silica shaped phase change material, wherein the cement is silicate cement with a strength grade of 52.

5.

2. The high-strength carbon-fixing aerated concrete according to claim 1, characterized in that: The catalyst includes a liquid catalyst and a powder catalyst. The liquid catalyst includes maleic acid, hydrogen peroxide, sodium hydroxide and distilled water. The powder catalyst includes calcium carbonate, calcium silicate and calcium hydroxide.

3. The high-strength carbon-fixing aerated concrete according to claim 2, characterized in that: The weight ratio of the powder catalyst to the liquid catalyst is (15-20):

1.

4. The high-strength carbon-fixing aerated concrete according to claim 3, characterized in that: The powder catalyst consists of calcium carbonate, calcium silicate and calcium hydroxide in a weight ratio of (2-4):(2-4):(1-2).

5. The high-strength carbon-fixing aerated concrete according to claim 4, characterized in that: The particle size of the calcium carbonate particles in the powder catalyst is ≤20 μm.

6. The high-strength carbon-fixing aerated concrete according to claim 3, characterized in that: The preparation method of the liquid catalyst comprises the following steps: Prepare a sodium hydroxide solution with a concentration of 0.15 mol / L for later use; Mix maleic acid and distilled water, heat in a 70°C water bath and stir until completely dissolved; A 30% by mass hydrogen peroxide solution is taken, and the sodium hydroxide solution and the hydrogen peroxide solution are added to the mixed solution of maleic acid and distilled water and stirred, wherein the mass ratio of the sodium hydroxide solution, the hydrogen peroxide solution, the maleic acid, and the distilled water is 3:1:3:3, to obtain the liquid catalyst.

7. The high-strength carbon-fixing aerated concrete according to claim 1, characterized in that: The fumed silica shaping phase change material is decanoic acid-hexadecanol and / or polyethylene glycol.

8. The high-strength carbon-fixing aerated concrete according to claim 1, characterized in that: The fumed silica shaped phase change material is encapsulated in microcapsules.

9. A method for preparing high-strength carbon-fixing aerated concrete according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: S1. Weigh the raw materials according to the experimental ratio, prepare the aluminum powder paste into a suspension, and put the remaining raw materials into a closed mixer and stir for 2-4 minutes; S2. Introduce CO2 gas into the mixer, keep the mixer running for 60-120 seconds, then add the aluminum powder suspension and continue stirring; S3. Pour the slurry into the test mold to a height not less than two-thirds of the test mold height. Let it stand for a while before demoulding. At the same time, cut off the upper bread head of the test block. S4. Completely immerse the test block in the curing box for water curing.

10. The preparation method according to claim 9, characterized in that The following conditions are met: a. In step S2, the amount of CO2 introduced is 0.15-0.25 parts by weight; b. In step S2, the aluminum powder suspension is added and stirred for 30-50 seconds; c. In step S3, the pouring temperature is 45-50°C and the standing time is 2-4 hours; d. In step S4, the curing period is 28 days.

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