Lightweight high-strength building material and preparation method thereof

Abstract

The invention discloses a lightweight high-strength building material and a preparation method thereof, belongs to the technical field of building material preparation, and aims to solve the technical problem that the lightweight and heat-insulating properties of a building material in the prior art need to be further improved. The light high-strength building material is prepared from the following raw materials in parts by weight: 81 to 148 parts of composite slurry, 20 to 30 parts of composite aerogel, 8 to 10 parts of silicon nitride fiber, 3 to 5 parts of a polycarboxylic acid water reducing agent, 10 to 15 parts of a 30wt% hydrogen peroxide solution and 20 to 25 parts of an alkali activator, a calcium-aluminum structure is modified in the aerogel, the compatibility of the aerogel and inorganic building material components is enhanced, under the alkaline condition, aluminum powder introduced into the aerogel reacts with hydrogen peroxide to decompose and release gas, the gas slow release effect is achieved through the aerogel pore structure, bubbles are evenly distributed, and the thermal insulation performance of the aerogel is improved. And finally, the light high-strength thermal insulation building material is prepared.

Description

Technical Field

[0001] The present invention relates to the technical field of building material preparation, and particularly relates to a lightweight and high-strength building material and a preparation method thereof. Background Art

[0002] Lightweight and high-strength building materials play an important role in modern architecture, especially in the fields of high-rise buildings and energy-saving buildings. Compared with traditional concrete, lightweight and high-strength materials can significantly reduce the self-weight of buildings, improve construction efficiency, reduce the foundation burden, and perform excellently in seismic performance. By introducing new lightweight aggregates, nanotechnology or aerogel and other strengthening components, such materials not only maintain the high strength of the structure but also effectively reduce the density. Lightweight and high-strength materials usually have excellent heat insulation performance. The high porosity of their internal structure can effectively hinder heat transfer, thereby improving the heat preservation effect of the building, which is particularly important for energy-saving buildings, can reduce energy consumption, lower operating costs, and improve indoor comfort at the same time.

[0003] The prior art CN116396095B discloses a lightweight heat-insulating brick and a preparation method thereof. The preparation method includes the following steps: Step 1: Weigh waste mud from an electric porcelain factory, molecular sieve waste, waste rice husk ash, yellow dextrin and water in a certain ratio and put them into a mixer, and stir at room temperature for a certain time to obtain a lightweight heat-insulating brick blank; Step 2: Transfer the lightweight heat-insulating brick blank into a mold, press and form it, and demold it to obtain a lightweight heat-insulating brick green body; Step 3: After the lightweight heat-insulating brick green body is left standing at room temperature for a certain time, transfer it into a sintering furnace, heat it up to a certain temperature, keep it warm for a certain time, and then cool it to room temperature with the furnace to obtain the lightweight heat-insulating brick. The lightweight heat-insulating brick prepared by the present invention has the advantages of low bulk density, small thermal conductivity, good strength stability, etc.

[0004] However, the above-mentioned invention obtains a lightweight heat-insulating building material by mixing and stirring waste mud from an electric porcelain factory, molecular sieve waste, waste rice husk ash, yellow dextrin and water and then roasting them. However, the above materials use the molecular sieve structure and organic components as the source of the pore structure. Due to the large polarity difference between inorganic materials and organic components, when mixing, it will cause uneven dispersion of the materials, resulting in uneven pore structure of the materials. Moreover, the internal part of the existing building materials lacks elastic component support and is difficult to absorb and disperse impact energy when being impacted, resulting in collapse. Therefore, the heat insulation and lightweight performance and strength of this material need to be further improved.

[0005] In view of the technical defects in this regard, a solution is now proposed. Summary of the Invention

[0006] The object of the present invention is to provide a lightweight and high-strength building material and a preparation method thereof, aiming to solve the technical problem that the lightweight and heat insulation performance of building materials in the prior art need to be further improved.

[0007] The object of the present invention can be achieved by the following technical solutions:

[0008] A lightweight and high-strength building material, comprising the following raw materials by weight: 81 - 148 parts of composite slurry, 20 - 30 parts of composite aerogel, 10 - 15 parts of 30wt% hydrogen peroxide solution, and 20 - 25 parts of alkali activator;

[0009] The preparation method of the composite aerogel comprises the following steps:

[0010] A1. Add nano-aluminum powder, absolute ethanol, triethylamine, and mercaptopropyltrimethoxysilane into a reaction kettle, raise the temperature of the reaction kettle to 30 - 50°C, keep warm and stir for 30 - 40 min, and perform post-treatment to obtain modified aluminum powder;

[0011] The reaction principle for preparing the modified aluminum powder is as follows: Under the catalysis of heating conditions, triethylamine promotes the deprotonation of the mercapto group to generate thiolate anions, which react with the active sites on the aluminum powder, and finally the modified aluminum powder is prepared.

[0012] A2. Transfer the modified aluminum powder, modified aerogel, and deionized water to a high-pressure reaction kettle, raise the temperature of the high-pressure reaction kettle to 160 - 180°C, keep warm for 20 - 24 h, then take out the modified aerogel and wash it 3 - 5 times with absolute ethanol and deionized water, and perform post-treatment to obtain the composite aerogel.

[0013] The reaction principle for preparing the composite aerogel is as follows: The high-pressure reaction kettle uses high pressure to inhibit the boiling of water and increase the boiling point of water, thereby forming hydrothermal conditions. During the hydrothermal process, the silanol structure generated by the hydrolysis of the cross-linked siloxane structure on the modified aluminum powder reacts with the modified aerogel to form a cross-linked structure, and finally the composite aerogel is prepared by supercritical fluid drying.

[0014] Further, in step A1, the stirring rate of the reaction kettle is 360 - 480 rpm, and the dosage ratio of nano-aluminum powder, ethanol, triethylamine, and mercaptopropyltrimethoxysilane is 4 - 5 g:40 - 50 mL:1 - 2 g:6 - 7 g. The post-treatment includes: after the reaction is completed, when the temperature of the reaction kettle drops to room temperature, filter the reaction solution to collect the filter cake, wash the filter cake 3 - 5 times with absolute ethanol and deionized water, transfer the filter cake to a drying oven at 60 - 80°C for vacuum drying until the filter cake reaches a constant weight, and obtain the modified aluminum powder;

[0015] Further, in step A2, the dosage ratio of the modified aluminum powder, the modified aerogel and deionized water is 3-4 g: 10-12 g: 80-100 mL. The post-treatment includes: after the reaction is completed, when the temperature of the reaction kettle drops to room temperature, take out the inner liner of the reaction kettle and open the cover, transfer the inner liner of the reaction kettle to a constant temperature drying oven, raise the temperature of the constant temperature drying oven to 80-90 °C, and perform constant temperature treatment for 1-2 h to obtain the composite aerogel.

[0016] Further, the preparation method of the modified aerogel includes the following steps:

[0017] B1. Add the modified cenospheres, deionized water and polyvinyl alcohol into the reaction kettle, stir at room temperature for 10-15 min, adjust the pH of the reaction system to 8-10 with saturated sodium hydroxide solution, and add methyltrimethoxysilane to the reaction kettle. After keeping warm and stirring for 2-3 h, add the modifier to the reaction kettle and keep warm for reaction for 20-30 min to obtain the composite gel;

[0018] B2. Immerse the composite gel in ethanol, let it stand for 12-16 h, repeat the immersion three times, and obtain the modified aerogel through post-treatment.

[0019] The reaction principle for preparing the modified aerogel is as follows: under alkaline conditions, methyltrimethoxysilane hydrolyzes to form silanol, which reacts with the active hydroxyl groups on the modified cenospheres to generate a gel structure. The calcium-aluminum components in the modifier further hydrolyze to modify the gel, and finally the modified aerogel is prepared by supercritical fluid drying.

[0020] Further, in step B1, the stirring rate of the reaction kettle is 360-480 rpm, and the dosage ratio of the modified cenospheres, deionized water, polyvinyl alcohol and 8-(trimethoxysilyl) octylamine, methyltrimethoxysilane and the modifier is 5-6 g: 30-35 mL: 1-2 g: 10-12 g: 18-20 g. The modifier is obtained by mixing calcium nitrate and aluminum nitrate according to the dosage ratio of 4 g: 5 g.

[0021] Further, in step B2, the post-treatment includes: transfer the composite gel to a high-pressure reaction kettle, after the temperature of the high-pressure reaction kettle rises to 40-50 °C, introduce carbon dioxide gas into the high-pressure reaction kettle, control the pressure to be 12 MPa, and perform constant temperature and constant pressure treatment for 2-3 h to obtain the modified aerogel.

[0022] Further, the preparation method of the modified cenospheres includes the following steps:

[0023] C1. Add the cenospheres and sodium hydroxide aqueous solution into the reaction kettle and stir. Raise the temperature of the reaction kettle to 50-70 °C, keep warm and react for 1-2 h, and obtain the activated cenospheres through post-treatment;

[0024] C2. Add activated cenospheres, triethylamine, and N,N-dimethylformamide into a reaction kettle, introduce nitrogen for protection, add a modification solution into the reaction kettle, react for 40 - 60 min, and perform post-treatment to obtain modified cenospheres.

[0025] The reaction principle for preparing modified cenospheres is as follows: Under the catalysis of heating and alkaline conditions, the cenospheres undergo an alkali etching reaction to form an epoxy active hydroxyl structure, obtaining active cenospheres. Then, under the catalysis of triethylamine, the active free radicals formed by the ring-opening of the epoxy group on glycidyltrimethoxysilane react with the active structure on the active cenospheres, and finally, modified cenospheres are prepared.

[0026] Further, in step C1, the stirring rate of the reaction kettle is 360 - 480 rpm, the dosage ratio of cenospheres to sodium hydroxide aqueous solution is 1 - 2 g:10 - 15 mL, the concentration of the sodium hydroxide aqueous solution is 0.8 - 1.2 moL / L, and the post-treatment includes: After the reaction is completed, when the temperature of the reaction kettle drops to room temperature, filter the reaction solution to collect the filter cake, wash the filter cake 3 - 5 times with absolute ethanol and deionized water, transfer the filter cake to a drying oven at 60 - 80 °C for vacuum drying until the filter cake reaches a constant weight, and obtain activated cenospheres;

[0027] Further, in step C2, the dosage ratio of activated cenospheres, triethylamine, N,N-dimethylformamide, and the modification solution is 4 - 5 g:0.5 - 0.8 g:15 - 18 mL:8 - 10 mL. The modification solution is obtained by mixing glycidyltrimethoxysilane and N,N-dimethylformamide according to a dosage ratio of 1 - 2 g:5 mL. The post-treatment includes: After the reaction is completed, when the temperature of the reaction kettle drops to room temperature, filter the reaction solution to collect the filter cake, wash the filter cake 3 - 5 times with absolute ethanol and deionized water, transfer the filter cake to a drying oven at 60 - 80 °C for vacuum drying until the filter cake reaches a constant weight, and obtain modified cenospheres.

[0028] Further, the preparation method of the composite mud is: Add the mud matrix into a blender for stirring. After the mud matrix is mixed evenly, add deionized water into the blender and continue stirring for 20 - 30 min to obtain the composite mud.

[0029] Further, the stirring rate of the blender is 160 - 180 rpm, the dosage ratio of the mud matrix to deionized water is 65 - 108 g:16 - 40 g, and the mud matrix is obtained by mixing phosphogypsum, fly ash, and quicklime according to a dosage ratio of 40 - 60 g:20 - 40 g:5 - 8 g.

[0030] Further, the preparation method of the alkali activator is: Add sodium hydroxide powder into a reaction kettle, slowly add deionized water while stirring. After the addition of deionized water is completed, continue stirring until the system cools to room temperature, and then add water glass and continue stirring at room temperature for 5 - 8 min to obtain the alkali activator.

[0031] Furthermore, the stirring rate of the reaction kettle is 360 - 480 rpm, and the dosage ratio of sodium hydroxide powder, deionized water and water glass is 5 - 7 g: 28 - 30 g: 14 - 16 g.

[0032] A preparation method of a light and high-strength building material, comprising the following steps:

[0033] S1. Add the composite slurry into a stirrer, stir at room temperature for 10 - 12 min, then add composite aerogel, silicon nitride fiber, polycarboxylate water reducer, 30 wt% hydrogen peroxide solution and alkali activator into the stirrer, and continue to stir for 3 - 5 min to obtain foamed slurry;

[0034] S2. Transfer the foamed slurry to a mold. After the foaming is complete, use a spatula to scrape the bulges on the surface and cover the surface of the material with plastic wrap, and then perform post-treatment to obtain the building material.

[0035] Furthermore, in step S1, the stirring rate of the stirrer is 160 - 180 rpm; in step S2, the post-treatment operation is: transfer the mold to a standard curing box with a temperature of 25 °C and a humidity of 95%, cure at a constant temperature and humidity for 24 - 36 h, then demold and transfer the material to the standard curing box again for curing until the specified age to obtain the building material.

[0036] The present invention has the following beneficial effects:

[0037] 1. By modifying the calcium-aluminum structure inside the aerogel, the present invention enhances the compatibility between the aerogel and the inorganic building material components. Under alkaline conditions, the aluminum powder introduced inside reacts with hydrogen peroxide to decompose and release gas. Through the gas slow-release effect brought by the pore structure of the aerogel, the gas bubbles are evenly distributed. And a cenosphere material is introduced inside the aerogel. Adding cenospheres on the basis of silica aerogel, which contains a large number of closed air pores inside, can further improve the thermal insulation effect of the concrete, reduce heat conduction, and enhance its heat preservation performance. When used together with silica aerogel, it significantly reduces the overall density of the concrete, making the concrete lighter. At the same time, the cenospheres have a certain elasticity and buffering property, forming an elastic region inside the concrete, thereby enhancing the wear resistance and flexural strength of the concrete.

[0038] 2. The present invention introduces a composite aerogel in the preparation process of building materials. The aerogel significantly reduces the overall density of the material due to its low density and excellent pore structure, while improving the strength and mechanical properties of the material. The composite aerogel is loaded with nano-aluminum powder. Under the initiation of an alkali activator, the nano-aluminum powder reacts to release gas while hydrogen peroxide rapidly decomposes to release a large amount of gas, forming a tiny bubble structure, which promotes the foaming process of the material. The special pore structure of the aerogel can play a slow-release role in the gas release process, making the bubbles evenly distributed and avoiding uneven material structure caused by excessively fast release of bubbles. The composite of aerogel and nano-aluminum powder significantly reduces the thermal conductivity of the foamed building material, thereby greatly enhancing the thermal insulation performance of the material and improving its thermal isolation effect.

[0039] 3. The present invention introduces a calcium aluminum modifier in the process of preparing aerogel. The aerogel modified with calcium aluminum has better affinity with calcium ions in cement, promotes the combination of aerogel and cement, improves the dispersibility and stability of aerogel in cement matrix, thereby reducing the migration of certain harmful ions in concrete and improving the water resistance of building materials. The pore structure inside the aerogel is optimized by the modification of calcium aluminum ions, so that the aerogel has better thermal isolation ability, further improving the thermal insulation effect of concrete. Through the interaction with silica, calcium aluminum modification can help silica aerogel form a denser and stronger network structure, enhance the chemical structure stability of the aerogel, improve its mechanical properties, and thus improve the compressive strength and flexural strength of concrete. DETAILED DESCRIPTION

[0040] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only 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 are within the scope of protection of the present invention.

[0041] The phosphogypsum powder used in the present invention is purchased from Fuzhou Persian Gulf Chemical Co., Ltd. with the item number 2022001; the nano aluminum powder used in the present invention is purchased from Guangzhou Hongwu Material Technology Co., Ltd. with a particle size of 40 nm and a purity of 99.9%; the polycarboxylate water reducer used in the present invention is purchased from Nanjing Xinyi Synthetic Technology Co., Ltd. with a bulk density of 400-700 kg / m3 and a model number of 1903.

[0042] Example 1

[0043] This embodiment provides a method for preparing modified floating beads for preparing lightweight and high-strength building materials, comprising the following steps:

[0044] Step ①: Preparation of activated floating beads

[0045] Weigh: 100.0 g of cenospheres and 1000.0 mL of 0.8 mol / L sodium hydroxide aqueous solution are added to a reaction kettle and stirred. The stirring rate of the reaction kettle is 360 rpm, the temperature of the reaction kettle is raised to 50 °C, and the reaction is carried out under insulation for 1 h. After the reaction is completed, after the temperature of the reaction kettle is lowered to room temperature, the reaction solution is filtered by suction to collect the filter cake. The filter cake is washed 3 times with absolute ethanol and deionized water, and the filter cake is transferred to a drying oven at 60 °C for vacuum drying until the filter cake reaches a constant weight, obtaining activated cenospheres.

[0046] Step ②, preparation of modified cenospheres

[0047] Weigh: 100.0 g of glycidyltrimethoxysilane and 500.0 mL of N,N-dimethylformamide are mixed to obtain a modification solution;

[0048] Weigh: 400.0 g of activated cenospheres, 50.0 g of triethylamine and 1500.0 mL of N,N-dimethylformamide are added to a reaction kettle, protected by nitrogen gas. 800.0 mL of the modification solution is added to the reaction kettle, and the reaction is carried out for 40 min. After the reaction is completed, after the temperature of the reaction kettle is lowered to room temperature, the reaction solution is filtered by suction to collect the filter cake. The filter cake is washed 3 times with absolute ethanol and deionized water, and the filter cake is transferred to a drying oven at 60 °C for vacuum drying until the filter cake reaches a constant weight, obtaining modified cenospheres.

[0049] Example 2

[0050] This example provides a preparation method of modified cenospheres for preparing a lightweight and high-strength building material, including the following steps:

[0051] Step ①, preparation of activated cenospheres

[0052] Weigh: 200.0 g of cenospheres and 1500.0 mL of 1.2 mol / L sodium hydroxide aqueous solution are added to a reaction kettle and stirred. The stirring rate of the reaction kettle is 480 rpm, the temperature of the reaction kettle is raised to 70 °C, and the reaction is carried out under insulation for 2 h. After the reaction is completed, after the temperature of the reaction kettle is lowered to room temperature, the reaction solution is filtered by suction to collect the filter cake. The filter cake is washed 5 times with absolute ethanol and deionized water, and the filter cake is transferred to a drying oven at 80 °C for vacuum drying until the filter cake reaches a constant weight, obtaining activated cenospheres.

[0053] Step ②, preparation of modified cenospheres

[0054] Weigh: 200.0 g of glycidyltrimethoxysilane and 500.0 mL of N,N-dimethylformamide are mixed to obtain a modification solution;

[0055] Weigh: 500.0 g of activated hollow beads, 80.0 g of triethylamine and 1800 mL of N,N-dimethylformamide are added to a reaction kettle, protected by nitrogen gas. 1000.0 mL of modifier solution is added to the reaction kettle, and the reaction is carried out for 60 min. After the reaction is completed, when the temperature of the reaction kettle drops to room temperature, the reaction solution is filtered to collect the filter cake. The filter cake is washed 5 times with absolute ethanol and deionized water, and then the filter cake is transferred to a drying oven at 80 °C for vacuum drying until the filter cake reaches a constant weight, obtaining modified hollow beads.

[0056] Example 3

[0057] This example provides a preparation method of modified hollow beads for preparing lightweight and high-strength building materials, including the following steps:

[0058] Step ①, prepare activated hollow beads

[0059] Weigh: 150.0 g of hollow beads and 1200.0 mL of 1 moL / L sodium hydroxide aqueous solution are added to a reaction kettle and stirred. The stirring rate of the reaction kettle is 420 rpm, and the temperature of the reaction kettle is raised to 60 °C and kept warm for 2 h. After the reaction is completed, when the temperature of the reaction kettle drops to room temperature, the reaction solution is filtered to collect the filter cake. The filter cake is washed 4 times with absolute ethanol and deionized water, and then the filter cake is transferred to a drying oven at 70 °C for vacuum drying until the filter cake reaches a constant weight, obtaining activated hollow beads.

[0060] Step ②, prepare modified hollow beads

[0061] Weigh: 150.0 g of glycidoxytrimethoxysilane and 500.0 mL of N,N-dimethylformamide are mixed to obtain a modifier solution;

[0062] Weigh: 450.0 g of activated hollow beads, 60.0 g of triethylamine and 1600.0 mL of N,N-dimethylformamide are added to a reaction kettle, protected by nitrogen gas. 900.0 mL of modifier solution is added to the reaction kettle, and the reaction is carried out for 50 min. After the reaction is completed, when the temperature of the reaction kettle drops to room temperature, the reaction solution is filtered to collect the filter cake. The filter cake is washed 4 times with absolute ethanol and deionized water, and then the filter cake is transferred to a drying oven at 70 °C for vacuum drying until the filter cake reaches a constant weight, obtaining modified hollow beads.

[0063] Example 4

[0064] This example provides a preparation method of modified aerogel for preparing lightweight and high-strength building materials, including the following steps:

[0065] Step Ⅰ, prepare composite gel

[0066] Weigh: 400.0 g of calcium nitrate and 500.0 g of aluminum nitrate are mixed to obtain a modifier;

[0067] Weigh: 500.0 g of the modified cenospheres prepared in Example 1, 3000.0 mL of deionized water, and 100.0 g of polyvinyl alcohol were added to a reaction kettle. The stirring rate of the reaction kettle was 360 rpm, and it was stirred at room temperature for 10 min. The pH of the reaction system was adjusted to 8 using saturated sodium hydroxide solution, and 1000.0 g of methyltrimethoxysilane was added to the reaction kettle. After maintaining the temperature and stirring for 2 h, 1800.0 g of modifier was added to the reaction kettle, and the reaction was carried out at a constant temperature for 20 min to obtain a composite gel.

[0068] Step II. Preparation of modified aerogel

[0069] Weigh: 500.0 g of the composite gel was soaked in ethanol and allowed to stand for 12 h. After repeating the soaking three times, the composite gel was transferred to a high-pressure reaction kettle. After the temperature of the high-pressure reaction kettle was raised to 40 °C, carbon dioxide gas was introduced into the high-pressure reaction kettle, and the pressure was controlled to be 12 MPa. After constant temperature and pressure treatment for 2 h, a modified aerogel was obtained.

[0070] Example 5

[0071] This example provides a preparation method of a modified aerogel for preparing a lightweight and high-strength building material, including the following steps:

[0072] Step I. Preparation of composite gel

[0073] Weigh: 400.0 g of calcium nitrate and 500.0 g of aluminum nitrate were mixed to obtain a modifier;

[0074] Weigh: 600.0 g of the modified cenospheres prepared in Example 2, 3500.0 mL of deionized water, and 200.0 g of polyvinyl alcohol were added to a reaction kettle. The stirring rate of the reaction kettle was 480 rpm, and it was stirred at room temperature for 15 min. The pH of the reaction system was adjusted to 10 using saturated sodium hydroxide solution, and 1200.0 g of methyltrimethoxysilane was added to the reaction kettle. After maintaining the temperature and stirring for 3 h, 2000.0 g of modifier was added to the reaction kettle, and the reaction was carried out at a constant temperature for 30 min to obtain a composite gel.

[0075] Step II. Preparation of modified aerogel

[0076] Weigh: 500.0 g of the composite gel was soaked in ethanol and allowed to stand for 16 h. After repeating the soaking three times, the composite gel was transferred to a high-pressure reaction kettle. After the temperature of the high-pressure reaction kettle was raised to 50 °C, carbon dioxide gas was introduced into the high-pressure reaction kettle, and the pressure was controlled to be 12 MPa. After constant temperature and pressure treatment for 3 h, a modified aerogel was obtained.

[0077] Example 6

[0078] This example provides a preparation method of a modified aerogel for preparing a lightweight and high-strength building material, including the following steps:

[0079] Step Ⅰ: Prepare the composite gel

[0080] Weigh: 400.0 g of calcium nitrate and 500.0 g of aluminum nitrate and mix them to obtain the modifier;

[0081] Weigh: 540.0 g of the modified cenospheres prepared in Example 3, 3200.0 mL of deionized water and 160.0 g of polyvinyl alcohol and add them to the reaction kettle. The stirring rate of the reaction kettle is 420 rpm. Stir at room temperature for 12 min. Use saturated sodium hydroxide solution to adjust the pH of the reaction system to 9, and add 1100.0 g of methyltrimethoxysilane to the reaction kettle. After heat-preserving and stirring for 3 h, add 1800.0 g of the modifier to the reaction kettle and react at a constant temperature for 25 min to obtain the composite gel.

[0082] Step Ⅱ: Prepare the modified aerogel

[0083] Weigh: 500.0 g of the composite gel, soak it in ethanol, and let it stand for 15 h. Repeat the soaking three times, then transfer the composite gel to the autoclave. After the temperature of the autoclave rises to 48 °C, introduce carbon dioxide gas into the autoclave, control the pressure to be 12 MPa, and perform isothermal and isobaric treatment for 3 h to obtain the modified aerogel.

[0084] Example 7

[0085] This example provides a preparation method of a composite aerogel for preparing a light and high-strength building material, including the following steps:

[0086] Step (1): Prepare the modified aluminum powder

[0087] Weigh: 400.0 g of nano-aluminum powder, 4000.0 mL of absolute ethanol, 100.0 g of triethylamine and 600.0 g of mercaptopropyltrimethoxysilane and add them to the reaction kettle. The stirring rate of the reaction kettle is 360 rpm. Raise the temperature of the reaction kettle to 30 °C and stir at a constant temperature for 30 min. After the reaction is completed, wait for the temperature of the reaction kettle to drop to room temperature, then filter the reaction solution to collect the filter cake, wash the filter cake 3 times with absolute ethanol and deionized water, and transfer the filter cake to a drying oven at 60 °C for vacuum drying until the filter cake reaches a constant weight to obtain the modified aluminum powder.

[0088] Step (2): Prepare the composite aerogel

[0089] Weigh: 300.0 g of modified aluminum powder, 1000.0 g of modified aerogel and 8000.0 mL of deionized water, transfer them to an autoclave. Raise the temperature of the autoclave to 160 °C, keep it warm for 20 h, then take out the modified aerogel and wash it 3 times with absolute ethanol and deionized water. After the reaction is completed, wait for the temperature of the autoclave to drop to room temperature, take out the inner liner of the autoclave and open the cover, transfer the inner liner of the autoclave to a constant temperature drying oven, raise the temperature of the constant temperature drying oven to 80 °C, and carry out constant temperature treatment for 1 h to obtain the composite aerogel.

[0090] Example 8

[0091] This example provides a preparation method of a composite aerogel for preparing a lightweight and high-strength building material, including the following steps:

[0092] Step (1), prepare modified aluminum powder

[0093] Weigh: 500.0 g of nano-aluminum powder, 5000.0 mL of absolute ethanol, 200.0 g of triethylamine and 700.0 g of mercaptopropyltrimethoxysilane, add them to a reaction kettle, the stirring rate of the reaction kettle is 480 rpm, raise the temperature of the reaction kettle to 50 °C, keep it warm and stir for 40 min. After the reaction is completed, wait for the temperature of the reaction kettle to drop to room temperature, then filter the reaction solution by suction to collect the filter cake, wash the filter cake 5 times with absolute ethanol and deionized water, transfer the filter cake to a drying oven at 80 °C and vacuum dry it until the filter cake reaches a constant weight to obtain the modified aluminum powder.

[0094] Step (2), prepare the composite aerogel

[0095] Weigh: 400.0 g of modified aluminum powder, 1200.0 g of modified aerogel and 10000.0 mL of deionized water, transfer them to an autoclave. Raise the temperature of the autoclave to 180 °C, keep it warm for 24 h, then take out the modified aerogel and wash it 5 times with absolute ethanol and deionized water. After the reaction is completed, wait for the temperature of the autoclave to drop to room temperature, take out the inner liner of the autoclave and open the cover, transfer the inner liner of the autoclave to a constant temperature drying oven, raise the temperature of the constant temperature drying oven to 90 °C, and carry out constant temperature treatment for 2 h to obtain the composite aerogel.

[0096] Example 9

[0097] This example provides a preparation method of a composite aerogel for preparing a lightweight and high-strength building material, including the following steps:

[0098] Step (1), prepare modified aluminum powder

[0099] Weigh 450.0 g of nano-aluminum powder, 4800.0 mL of absolute ethanol, 160.0 g of triethylamine, and 640.0 g of mercaptopropyltrimethoxysilane and add them to the reaction kettle. The stirring rate of the reaction kettle is 420 rpm. Raise the temperature of the reaction kettle to 40 °C, keep stirring for 36 min. After the reaction is completed, wait for the temperature of the reaction kettle to drop to room temperature, then filter the reaction solution to collect the filter cake, wash the filter cake 4 times with absolute ethanol and deionized water, transfer the filter cake to a drying oven at 70 °C and dry it in vacuum until the filter cake reaches a constant weight to obtain modified aluminum powder.

[0100] Step (2), prepare the composite aerogel

[0101] Weigh: 360.0 g of modified aluminum powder, 1200.0 g of modified aerogel, and 9000.0 mL of deionized water and transfer them to a high-pressure reaction kettle. Raise the temperature of the high-pressure reaction kettle to 170 °C, keep it warm for 21 h, then take out the modified aerogel and wash it 4 times with absolute ethanol and deionized water. After the reaction is completed, wait for the temperature of the reaction kettle to drop to room temperature, take out the inner liner of the reaction kettle and open the cover, transfer the inner liner of the reaction kettle to a constant-temperature drying oven, raise the temperature of the constant-temperature drying oven to 84 °C, and keep it at a constant temperature for 2 h to obtain the composite aerogel.

[0102] Example 10

[0103] This example provides a preparation method of a lightweight and high-strength building material, which includes the following steps:

[0104] Step one, prepare the composite slurry

[0105] Weigh: 400.0 g of phosphogypsum, 200.0 g of fly ash, and 50.0 g of quicklime and add them to a mixer for stirring. The stirring rate of the mixer is 160 rpm. After the slurry matrix is mixed evenly, add 160.0 g of deionized water to the mixer and continue stirring for 20 min to obtain the composite slurry.

[0106] Step two, prepare the alkali activator

[0107] Weigh: 50.0 g of sodium hydroxide powder and add it to the reaction kettle. Slowly add 280.0 g of deionized water under stirring. The stirring rate is 360 rpm. After the addition of deionized water is completed, continue stirring until the system cools to room temperature, then add 140.0 g of water glass and continue stirring at room temperature for 5 min to obtain the alkali activator.

[0108] Step three, prepare the foam slurry

[0109] Weigh: Add 810.0 g of composite mud into a stirrer. Set the stirring rate of the stirrer to 160 rpm. After stirring for 10 min at room temperature, add 200.0 g of the composite aerogel prepared in Example 7, 80.0 g of silicon nitride fiber, 30.0 g of polycarboxylate water reducer, 100.0 g of 30 wt% hydrogen peroxide solution and 200.0 g of alkali activator into the stirrer. After continuing to stir for 3 min, foamed mud is obtained.

[0110] Step 4. Prepare building materials

[0111] Weigh: Transfer 500.0 g of foamed mud to a mold. After the foaming is complete, use a spatula to scrape the bulges on the surface flat and cover the surface of the material with plastic wrap. Transfer the mold to a standard curing box at a temperature of 25 °C and a humidity of 95%. After curing at a constant temperature and humidity for 24 h, demold and transfer the material to the standard curing box again for curing for 7 days to obtain building materials.

[0112] Example 11

[0113] This example provides a method for preparing a lightweight and high-strength building material, which includes the following steps:

[0114] Step 1. Prepare composite mud

[0115] Weigh: Add 600.0 g of phosphogypsum, 400.0 g of fly ash and 80.0 g of quicklime into a mixer and stir. The stirring rate of the mixer is 180 rpm. After the mud matrix is mixed evenly, add 400.0 g of deionized water into the mixer. After continuing to stir for 30 min, composite mud is obtained.

[0116] Step 2. Prepare alkali activator

[0117] Weigh: Add 70.0 g of sodium hydroxide powder into a reaction kettle. Slowly add 300.0 g of deionized water under stirring. The stirring rate is 480 rpm. After the addition of deionized water is completed, continue to stir until the system cools to room temperature. Then add 160.0 g of water glass and continue to stir at room temperature for 8 min to obtain an alkali activator.

[0118] Step 3. Prepare foamed mud

[0119] Weigh: Add 1480.0 g of composite mud into a stirrer. Set the stirring rate of the stirrer to 180 rpm. After stirring for 12 min at room temperature, add 300.0 g of the composite aerogel prepared in Example 8, 100.0 g of silicon nitride fiber, 50.0 g of polycarboxylate water reducer, 150.0 g of 30 wt% hydrogen peroxide solution and 250.0 g of alkali activator into the stirrer. After continuing to stir for 5 min, foamed mud is obtained.

[0120] Step 4. Prepare building materials

[0121] Weigh: Transfer 500.0 g of foam mud into a mold. After complete foaming, use a spatula to scrape the bulges on the surface flat and cover the material surface with plastic wrap. Transfer the mold to a standard curing box at a temperature of 25 °C and a humidity of 95%. After constant temperature and humidity curing for 36 h, demold and transfer the material to the standard curing box again for curing for 7 days to obtain the building material.

[0122] Example 12

[0123] This example provides a preparation method of a lightweight and high-strength building material, including the following steps:

[0124] Step 1: Prepare composite mud

[0125] Weigh: Add 500.0 g of phosphogypsum, 300.0 g of fly ash, and 60.0 g of quicklime into a mixer and stir. The stirring rate of the mixer is 180 rpm. After the mud matrix is mixed evenly, add 320.0 g of deionized water to the mixer and continue stirring for 30 min to obtain the composite mud.

[0126] Step 2: Prepare alkali activator

[0127] Weigh: Add 60.0 g of sodium hydroxide powder into a reaction kettle, slowly add 300.0 g of deionized water under stirring, and the stirring rate is 480 rpm. After the addition of deionized water is completed, continue stirring until the system cools to room temperature. Then add 150.0 g of water glass and continue stirring at room temperature for 6 min to obtain the alkali activator.

[0128] Step 3: Prepare foam mud

[0129] Weigh: Add 1080.0 g of composite mud into a stirrer. Set the stirring rate of the stirrer to 180 rpm. After stirring at room temperature for 12 min, add 240.0 g of the composite aerogel prepared in Example 9, 90.0 g of silicon nitride fiber, 40.0 g of polycarboxylate water reducer, 120.0 g of 30 wt% hydrogen peroxide solution, and 210.0 g of alkali activator to the stirrer, and continue stirring for 4 min to obtain the foam mud.

[0130] Step 4: Prepare building material

[0131] Weigh: Transfer 500.0 g of foam mud into a mold. After complete foaming, use a spatula to scrape the bulges on the surface flat and cover the material surface with plastic wrap. Transfer the mold to a standard curing box at a temperature of 25 °C and a humidity of 95%. After constant temperature and humidity curing for 30 h, demold and transfer the material to the standard curing box again for curing for 7 days to obtain the building material.

[0132] Comparative Example 1

[0133] The difference between this comparative example and Example 12 is that in the preparation process of the composite aerogel used, in Step I of the preparation process of the modified aerogel used, the use of modified cenospheres is cancelled.

[0134] Comparative Example 2

[0135] The difference between this comparative example and Example 12 is that the modified aerogel used in the preparation of the composite aerogel is used to equivalently replace the composite aerogel.

[0136] Comparative Example 3

[0137] The difference between this comparative example and Example 12 is that the use of the composite aerogel is cancelled.

[0138] Performance test:

[0139] Refer to the standard GB / T 23294-2021 "Wear-resistant refractory materials" to test the room-temperature wear resistance, room-temperature flexural strength, bulk density and thermal conductivity of the building materials prepared in Examples 10-12 and Comparative Examples 1-3;

[0140] Refer to the standard GB 23864-2023 "Fireproof sealing materials" to test the water resistance of the building materials prepared in Examples 10-12 and Comparative Examples 1-3; The specific data are shown in Table 1.

[0141] Table 1 - Performance test data table of each specimen

[0142]

[0143] Data analysis:

[0144] Referring to the data in Table 1 above for comparative analysis, the room-temperature wear resistance of the building materials prepared by the present invention is 4.8 cm 3 , the room-temperature flexural strength is 15.5 MPa, the bulk density is 1.7 g / cm 3 , the thermal conductivity is 0.058 W·(m·K) -1 and the water resistance is 17 d, and all data are better than those of the comparative examples;

[0145] Description: In the preparation process of building materials of the present invention, a composite aerogel is introduced. Due to its low density and excellent pore structure, the aerogel significantly reduces the overall density of the material, while improving the strength and mechanical properties of the material. The interior of the composite aerogel is loaded with nano-aluminum powder. Under the initiation of an alkali activator, while the nano-aluminum powder reacts to release gas, hydrogen peroxide decomposes rapidly, releasing a large amount of gas, forming a micro-bubble structure, which promotes the foaming process of the material. Moreover, the special pore structure of the aerogel can play a slow-release role during the gas release process, avoiding uneven material structure caused by too-fast bubble release. The combination of the foaming structure, aerogel and nano-aluminum powder significantly reduces the thermal conductivity of the foamed building materials, thus greatly enhancing the heat insulation performance of the material and improving its thermal insulation effect;

[0146] Description: In the process of preparing the aerogel of the present invention, a calcium-aluminum modifier is introduced. The aerogel modified by calcium-aluminum has better affinity with calcium ions in cement, promotes the combination of the aerogel and cement, improves the dispersibility of the aerogel and its stability in the cement substrate, thereby reducing the migration of certain harmful ions in the concrete and improving the water resistance of the building materials. Moreover, through the modification of calcium-aluminum ions, the pore structure inside the aerogel is optimized, enabling the aerogel to have better thermal insulation ability and further improving the heat insulation effect of the concrete. Through the interaction with silica, the calcium-aluminum modification can help the silica aerogel form a denser and more solid network structure, enhancing the chemical structure stability of the aerogel and improving its mechanical properties, thereby enhancing the compressive strength and flexural strength of the concrete;

[0147] Description: In the present invention, by modifying the calcium-aluminum structure inside the aerogel, the compatibility between the aerogel and inorganic building material components is enhanced. Under alkaline conditions, the aluminum powder and hydrogen peroxide introduced inside it react and decompose to release gas. The pore structure of the aerogel brings about a gas slow-release effect, making the bubble distribution uniform. Moreover, cenospheres are introduced inside the aerogel. Adding cenospheres on the basis of silica aerogel, which contain a large number of closed air pores inside, can further improve the thermal insulation effect of the concrete, reduce heat conduction, and enhance its heat insulation performance. When used together with silica aerogel, it significantly reduces the overall density of the concrete, making the concrete lighter. At the same time, cenospheres have a certain elasticity and buffering property, forming an elastic region inside the concrete, thereby enhancing the wear-resistant and flexural properties of the concrete.

[0148] The above content is merely an example and description of the structure of the present invention. Those skilled in the art of this technology can make various modifications or supplements to the described specific embodiments or use similar methods for substitution. As long as they do not deviate from the structure of the invention or exceed the scope defined by this claim book, they should fall within the protection scope of the present invention.

[0149] In the description of this specification, the descriptions referring to the terms "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples.

[0150] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the present invention to only the specific implementation manners. Obviously, according to the content of this specification, many modifications and changes can be made. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A lightweight and high-strength building material, characterized in that: The invention comprises the following raw materials in parts by weight: 81-148 parts of composite mud, 20-30 parts of composite aerogel, 8-10 parts of silicon nitride fiber, 3-5 parts of polycarboxylic acid water reducer, 10-15 parts of 30wt% hydrogen peroxide solution and 20-25 parts of alkali activator; The preparation method of the composite aerogel comprises the following steps: A1. Add nano aluminum powder, anhydrous ethanol, triethylamine and mercaptopropyltrimethoxysilane into a reactor, raise the temperature of the reactor to 30-50°C, keep warm and stir for 30-40 minutes, and post-treat to obtain modified aluminum powder; A2. The modified aluminum powder, modified aerogel and deionized water are transferred to a high-pressure reactor. The temperature of the high-pressure reactor is increased to 160-180°C. After keeping the temperature for 20-24 hours, the modified aerogel is taken out and washed 3-5 times with anhydrous ethanol and deionized water. The composite aerogel is obtained by post-treatment.

2. A lightweight and high-strength building material according to claim 1, characterized in that: In step A1, the usage ratio of nano aluminum powder, ethanol, triethylamine and mercaptopropyltrimethoxysilane is 4-5g:40-50mL:1-2g:6-7g; in step A2, the usage ratio of modified aluminum powder, modified aerogel and deionized water is 3-4g:10-12g:80-100mL.

3. A lightweight and high-strength building material according to claim 1, characterized in that: The preparation method of the modified aerogel comprises the following steps: B1. Add modified floating beads, deionized water and polyvinyl alcohol into a reactor, stir at room temperature for 10-15 minutes, adjust the pH of the reaction system to 8-10 with a saturated sodium hydroxide solution, add methyltrimethoxysilane into the reactor, keep stirring and react for 2-3 hours, add a modifier into the reactor, keep warm and react for 20-30 minutes, and obtain a composite gel; B2. Soak the composite gel in ethanol, let it stand for 12-16 hours, repeat the soaking three times, and post-treat to obtain the modified aerogel.

4. A lightweight and high-strength building material according to claim 3, characterized in that: In step B1, the amount ratio of modified floating beads, deionized water, polyvinyl alcohol and 8-(trimethoxysilyl)octylamine, methyltrimethoxysilane and modifier is 5-6g:30-35mL:1-2g:10-12g:18-20g, and the modifier is calcium nitrate and aluminum nitrate mixed in a ratio of 4g:5g.

5. A lightweight and high-strength building material according to claim 3, characterized in that: The preparation method of the modified floating beads comprises the following steps: C1. Add the floating beads and sodium hydroxide aqueous solution into the reactor and stir. The temperature of the reactor is raised to 50-70°C. The reaction is kept warm for 1-2 hours. The activated floating beads are obtained by post-processing. C2. Add activated floating beads, triethylamine and N,N-dimethylformamide into the reactor, introduce nitrogen protection, add modification liquid into the reactor, react for 40-60 minutes, and post-treat to obtain modified floating beads.

6. A lightweight and high-strength building material according to claim 5, characterized in that: In step C1, the dosage ratio of the floating beads and the sodium hydroxide aqueous solution is 1-2g:10-15mL, and the concentration of the sodium hydroxide aqueous solution is 0.8-1.2moL / L; in step C2, the dosage ratio of the activated floating beads, triethylamine, N,N-dimethylformamide and the modification liquid is 4-5g:0.5-0.8g:15-18mL:8-10mL, and the modification liquid is obtained by mixing epoxypropyltrimethoxysilane and N,N-dimethylformamide in a dosage ratio of 1-2g:5mL.

7. A lightweight and high-strength building material according to claim 1, characterized in that: The preparation method of the composite mud is as follows: adding the mud matrix into a mixer and stirring, after the mud matrix is ​​evenly mixed, adding deionized water into the mixer, and continuing stirring for 20-30 minutes to obtain the composite mud.

8. A lightweight and high-strength building material according to claim 7, characterized in that: The usage ratio of the mud matrix and deionized water is 65-108g:16-40g, and the mud matrix is ​​obtained by mixing phosphogypsum, fly ash and quicklime in a usage ratio of 40-60g:20-40g:5-8g.

9. The lightweight and high-strength building material according to claim 1, characterized in that: The preparation method of the alkaline activator is as follows: sodium hydroxide powder is added into a reaction kettle, deionized water is slowly added under stirring, and after the deionized water is added, stirring is continued until the system is cooled to room temperature, and then water glass is added, and stirring is continued at room temperature for 5-8 minutes to obtain the alkaline activator.

10. A method for preparing a lightweight and high-strength building material according to any one of claims 1 to 9, characterized in that: The method for preparing the lightweight and high-strength building material comprises the following steps: S1. Add the composite mud into a stirrer, stir for 10-12 minutes at room temperature, add the composite aerogel, silicon nitride fiber, polycarboxylic acid water reducer, 30wt% hydrogen peroxide solution and alkali activator into the stirrer, continue stirring for 3-5 minutes, and obtain foam mud; S2. Transfer the foam slurry to the mold. After the foaming is complete, use a scraper to flatten the raised parts of the surface and cover the surface of the material with plastic wrap. After post-processing, the building material is obtained.

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