Preparation method of SiO2 aerogel composite cement thermal insulation mortar

Abstract

The application relates to the technical field of thermal insulation building materials, and discloses a preparation method of SiO2 aerogel composite cement thermal insulation mortar, which comprises the following steps: adding a silane coupling agent and deionized water to form a solution, stirring SiO2 aerogel particles, and obtaining surface-modified SiO2 aerogel particles; adding cement, slaked lime, latex powder, an additive, silicon powder and deionized water into a stirring mold to obtain a cementing material; adding the SiO2 aerogel particles into the cementing material, simultaneously adding deionized water, a water-retaining agent, a thickening agent and a polycarboxylic acid water reducing agent to obtain white viscous granular cement thermal insulation mortar; uniformly applying the cement thermal insulation mortar in the mold by means of an operating scraper, hardening and drying, and obtaining a sample block of the aerogel composite cement thermal insulation mortar; the sample block has a low thermal conductivity, good thermal insulation performance, good easy-processing performance, a complete appearance after drying, high compressive strength and can meet the construction quality requirements.

Description

Technical Field

[0001] This invention relates to the field of thermal insulation building materials technology, and in particular to a method for preparing SiO2 aerogel composite cement thermal insulation mortar. Background Technology

[0002] SiO2 aerogel is a nanoscale thermal insulation material formed by gradually transforming a precursor liquid into a sol and gel, and then drying it to create a porous three-dimensional nanonetwork structure of interconnected SiO2 particles. Studies have shown that compared to other types of aerogels, such as carbon aerogels, carbide aerogels, nitride aerogels, graphene aerogels (GA), and quantum dot aerogels, SiO2 aerogel has significant advantages, including lighter weight, lower thermal conductivity, higher porosity, larger specific surface area, mature research and preparation methods, and greater application prospects. Faced with the current severe energy situation, building energy conservation places increasingly higher demands on the thermal insulation performance of buildings. The heat loss of buildings is mainly composed of the heat loss through the building envelope, accounting for approximately 73% to 77% of the total heat loss, while the exterior walls account for about 25% of the heat loss through heat transfer.

[0003] The prior art Chinese patent with authorization publication number CN104829196A discloses an aerogel-modified inorganic thermal insulation mortar and its application method to obtain an aerogel composite fiber thermal insulation material. By using silica aerogel to modify the inorganic thermal insulation mortar, the synergistic effect between the two can be used to obtain a thermal insulation material with comprehensive performance.

[0004] However, in the aforementioned existing technologies, the application of inorganic thermal insulation mortar is limited due to its high thermal conductivity and poor thermal insulation performance. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing SiO2 aerogel composite cement thermal insulation mortar, which solves the problem that the application of inorganic thermal insulation mortar is limited due to its high thermal conductivity and poor thermal insulation performance.

[0006] To achieve the above objectives, the present invention provides a method for preparing SiO2 aerogel composite cement thermal insulation mortar, comprising the following steps: adding a silane coupling agent and deionized water to form a solution, adding SiO2 aerogel particles and stirring to obtain surface-modified SiO2 aerogel particles; adding cement, quicklime, latex powder, admixtures, silica powder and the deionized water into a mixing mold to obtain a cementitious material; adding the SiO2 aerogel particles into the cementitious material, and simultaneously adding the deionized water, a water-retaining agent for thickening and a polycarboxylate superplasticizer to obtain a white, viscous, granular cement thermal insulation mortar; using a scraper to evenly spread the cement thermal insulation mortar into the mold, hardening and drying to obtain a sample block of aerogel composite cement thermal insulation mortar.

[0007] In the step of adding a silane coupling agent and deionized water to form a solution, then adding SiO2 aerogel particles and stirring to obtain surface-modified SiO2 aerogel particles: The silane coupling agent is one or more of γ-aminopropyltriethoxysilane, dimethyldiethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane. The silane coupling agent and the deionized water are prepared into a solution with a mass fraction of 5-10%, and stirred at a speed of 400-600 rpm for 24-36 hours.

[0008] In the step of adding cement, quicklime, latex powder, admixtures, silica fume, and deionized water into a mixing mold to obtain a cementitious material: The cement and the quicklime are mixed in a mass ratio of 1:6 to 10, and then the latex powder is added in a mass fraction of 15 to 30%, using deionized water as the solvent. The cement is one or both of white cement and gray cement, with a mesh size of 300 to 500. The quicklime is one or both of high-calcium quicklime, magnesium quicklime, and white jade quicklime. The latex powder is a copolymer of ethylene / vinyl acetate, a copolymer of vinyl acetate / ethylene tert-carbonate, or an acrylic acid copolymer powder. The mixing mold is used to stir at a low speed of 100 to 150 rpm for 3 to 6 minutes to obtain the cementitious material.

[0009] In the step of adding cement, quicklime, latex powder, admixtures, silica fume, and deionized water into a mixing mold to obtain a cementitious material: The mass fraction of the silica fume is 10% to 20%, and the silica fume selected is one of ferrosilicon silica fume, industrial silicon silica fume, or alloy silica fume.

[0010] In the step of adding the SiO2 aerogel particles to the cementitious material, and simultaneously adding deionized water, a water-retaining agent for thickening, and a polycarboxylate-based water-reducing agent to obtain the white, viscous, granular cement insulation mortar: The water-reducing agent has a mass fraction of 0.5-0.9%, and the selected water-reducing agent is one of lignin-based water-reducing agents, aminosulfonate-based water-reducing agents, or polycarboxylate-based water-reducing agents.

[0011] In the step of adding the SiO2 aerogel particles to the cementitious material, and simultaneously adding deionized water, a water-retaining agent for thickening, and a polycarboxylate-based water-reducing agent to obtain the white, viscous, granular cement insulation mortar: The water-retaining agent has a mass fraction of 0.12~0.4%, and the selected water-retaining agent is one of methylcellulose, hydroxypropyl methylcellulose or hydroxyethyl methylcellulose.

[0012] In the step of adding a silane coupling agent and deionized water to form a solution, then adding SiO2 aerogel particles and stirring to obtain surface-modified SiO2 aerogel particles: The SiO2 aerogel particles have a density of 60-120 kg / m³, measured using the volume-mass method; a particle size of 0.2-5 mm, measured using laser diffraction; a hydrophobicity of 60-99%, measured using the hydrophobicity method; a thermal conductivity of 0.013-0.02 W / m·K, measured using the plate heat flow meter method; and a compressive strength of 100-500 kPa, measured using the compression test method. All tests require temperature control at 21-25℃ and relative humidity control at 40-60%.

[0013] In the step of using a scraper to evenly apply the cement insulation mortar into a mold, allowing it to harden and dry, to obtain a sample block of aerogel composite cement insulation mortar: The density of the sample block is 230~270 kg / m3, and the method used is the volume-mass method; the compressive strength is 120~570 kPa, and the method used is the compression test method; the above tests require the temperature to be controlled at 21~25 ℃ and the relative humidity to be controlled at 40~60%.

[0014] This invention discloses a method for preparing SiO2 aerogel composite cement insulation mortar. The method involves adding a silane coupling agent and deionized water to form a solution, then adding SiO2 aerogel particles and stirring to obtain surface-modified SiO2 aerogel particles. Cement, quicklime, latex powder, admixtures, silica fume, and the deionized water are added to a mixing mold to obtain a cementitious material. The SiO2 aerogel particles are then added to the cementitious material, along with the deionized water, a water-retaining agent for thickening, and a polycarboxylate-based water-reducing agent, to obtain a white, viscous, granular cement insulation mortar. The cement insulation mortar is evenly applied to the mold with a scraper, hardened and dried to obtain a sample block of aerogel composite cement insulation mortar. Using readily available and inexpensive quicklime, white cement, and latex powder as raw materials, the SiO2 aerogel composite cement insulation mortar can be prepared through room temperature reaction conditions and normal pressure drying. This significantly shortens the preparation cycle and reduces the cost of the insulation mortar. The sample has a low thermal conductivity, good insulation performance, and excellent processability. The dried sample block has a complete appearance and high compressive strength, meeting construction quality requirements. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0016] Figure 1This is a flowchart of the preparation method of SiO2 aerogel composite cement thermal insulation mortar of the present invention.

[0017] Figure 2 This is a physical image of the aerogel thermal insulation mortar sample block of the present invention. Detailed Implementation

[0018] The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, but should not be construed as limiting the present invention.

[0019] First embodiment: Please refer to Figures 1 to 2 , Figure 1 This is a flowchart illustrating the steps of the preparation method of the SiO2 aerogel composite cement insulation mortar of the present invention. Figure 2 This is a physical image of the aerogel thermal insulation mortar sample block of the present invention.

[0020] This invention provides a method for preparing SiO2 aerogel composite cement insulation mortar, comprising the following steps: S1 is added to silane coupling agent and deionized water to form a solution, and then SiO2 aerogel particles are added and stirred to obtain surface-modified SiO2 aerogel particles. S2 adds cement, quicklime, latex powder, admixtures, silica fume, and deionized water into a mixing mold to obtain a cementitious material; S3 adds the SiO2 aerogel particles to the cementitious material, and simultaneously adds deionized water, a water-retaining agent for thickening, and a polycarboxylate superplasticizer to obtain the white, viscous, granular cement insulation mortar. S4 uses a scraper to evenly apply the cement insulation mortar into the mold, which then hardens and dries to obtain a sample block of aerogel composite cement insulation mortar.

[0021] In this embodiment, a solution is formed by adding a silane coupling agent and deionized water, and then SiO2 aerogel particles are added and stirred to obtain surface-modified SiO2 aerogel particles. Cement, quicklime, latex powder, admixtures, silica powder, and the deionized water are added to a mixing mold to obtain a cementitious material. The SiO2 aerogel particles are added to the cementitious material, along with the deionized water, a water-retaining agent for thickening, and a polycarboxylate superplasticizer, to obtain a white, viscous, granular cement insulation mortar. A scraper is used to apply the cement insulation mortar. The mortar is evenly applied to the mold, hardened and dried to obtain a sample block of aerogel composite cement insulation mortar. The SiO2 aerogel composite cement insulation mortar can be prepared by using readily available and inexpensive quicklime, white cement and latex powder as raw materials, through room temperature reaction conditions and normal pressure drying method. This greatly shortens the preparation cycle and cost of insulation mortar. The sample has a low thermal conductivity, good insulation performance, good processability, and the dried sample block has a complete appearance and high compressive strength, which can meet the construction quality requirements.

[0022] Furthermore, in the step of adding a silane coupling agent and deionized water to form a solution, then adding SiO2 aerogel particles and stirring to obtain surface-modified SiO2 aerogel particles: The silane coupling agent is one or more of γ-aminopropyltriethoxysilane, dimethyldiethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane. The silane coupling agent and the deionized water are prepared into a solution with a mass fraction of 5-10%, and stirred at a speed of 400-600 rpm for 24-36 hours.

[0023] In this embodiment, any one or more of the γ-aminopropyltriethoxysilane, the dimethyldiethoxysilane, and the γ-methacryloyloxypropyltrimethoxysilane are dissolved in water as silane coupling agents to prepare a silane coupling agent solution with a mass fraction of 5-10%. Then, SiO2 aerogel particles are added to the solution, and the mixture is stirred at a speed of 400-600 rpm for 24-36 h.

[0024] Furthermore, in the step of adding cement, quicklime, latex powder, admixtures, silica fume, and the deionized water into a mixing mold to obtain a cementitious material: The cement and the quicklime are mixed in a mass ratio of 1:6 to 10, and then the latex powder is added in a mass fraction of 15 to 30%, using deionized water as the solvent. The cement is one or both of white cement and gray cement, with a mesh size of 300 to 500. The quicklime is one or both of high-calcium quicklime, magnesium quicklime, and white jade quicklime. The latex powder is a copolymer of ethylene / vinyl acetate, a copolymer of vinyl acetate / ethylene tert-carbonate, or an acrylic acid copolymer powder. The mixing mold is used to stir at a low speed of 100 to 150 rpm for 3 to 6 minutes to obtain the cementitious material.

[0025] In this embodiment, the cement and the quicklime are mixed in a mass ratio of 1:6 to 10, and then the latex powder is added in a mass fraction of 15 to 30%, using deionized water as the solvent; the cement is one or both of white cement and gray cement, with a mesh size of 300 to 500; the quicklime is one or both of high-calcium quicklime, magnesium quicklime, and white jade quicklime; the latex powder is a copolymer of ethylene / vinyl acetate, a copolymer of vinyl acetate / ethylene tert-carbonate, or an acrylic acid copolymer powder; the mixing mold is used to stir at a low speed of 100 to 150 rpm for 3 to 6 minutes to obtain the cementitious material.

[0026] Furthermore, in the step of adding cement, quicklime, latex powder, admixtures, silica fume, and the deionized water into a mixing mold to obtain a cementitious material: The mass fraction of the silica fume is 10% to 20%, and the silica fume selected is one of ferrosilicon silica fume, industrial silicon silica fume, or alloy silica fume.

[0027] In this embodiment, the mass fraction of the silica fume is 10% to 20%, and the silica fume selected is one of ferrosilicon silica fume, industrial silicon silica fume, or alloy silica fume.

[0028] Furthermore, in the step of adding the SiO2 aerogel particles to the cementitious material, and simultaneously adding deionized water, a water-retaining agent for thickening, and a polycarboxylate-based water-reducing agent to obtain the white, viscous, granular cementitious thermal insulation mortar: The water-reducing agent has a mass fraction of 0.5-0.9%, and the selected water-reducing agent is one of lignin-based water-reducing agents, aminosulfonate-based water-reducing agents, or polycarboxylate-based water-reducing agents.

[0029] In this embodiment, the water-reducing agent has a mass fraction of 0.5-0.9%, and the selected water-reducing agent is one of lignin-based water-reducing agents, aminosulfonate-based water-reducing agents, or polycarboxylate-based water-reducing agents.

[0030] Furthermore, in the step of adding the SiO2 aerogel particles to the cementitious material, and simultaneously adding deionized water, a water-retaining agent for thickening, and a polycarboxylate-based water-reducing agent to obtain the white, viscous, granular cementitious thermal insulation mortar: The water-retaining agent has a mass fraction of 0.12~0.4%, and the selected water-retaining agent is one of methylcellulose, hydroxypropyl methylcellulose or hydroxyethyl methylcellulose.

[0031] In this embodiment, the water-retaining agent has a mass fraction of 0.12~0.4%, and the selected water-retaining agent is one of methylcellulose, hydroxypropyl methylcellulose or hydroxyethyl methylcellulose.

[0032] Furthermore, in the step of adding a silane coupling agent and deionized water to form a solution, then adding SiO2 aerogel particles and stirring to obtain surface-modified SiO2 aerogel particles: The SiO2 aerogel particles have a density of 60-120 kg / m³, measured using the volume-mass method; a particle size of 0.2-5 mm, measured using laser diffraction; a hydrophobicity of 60-99%, measured using the hydrophobicity method; a thermal conductivity of 0.013-0.02 W / m·K, measured using the plate heat flow meter method; and a compressive strength of 100-500 kPa, measured using the compression test method. All tests require temperature control at 21-25℃ and relative humidity control at 40-60%.

[0033] In this embodiment, the density of the SiO2 aerogel particles is 60-120 kg / m³, measured using the volumetric-mass method, and the testing standard is JC / T 2518-2019; the particle size is 0.2-5 mm, measured using laser diffraction, and the testing standard is GB / T 19077-2016; the hydrophobicity is 60-99%, measured using the hydrophobicity method, and the testing standard is GB / T 10299-2011; the thermal conductivity is 0.013~0.02 W / (m·K), measured using the plate heat flow meter method, and the testing standard is GB / T34336-2017; the compressive strength is 100-500 kPa, measured using the compression test method, and the testing standard is GB / T 34342-2017. All tests require the temperature to be controlled at 21~25 ℃ and the relative humidity to be controlled at 40~60%.

[0034] Furthermore, in the step of using a scraper to evenly apply the cement insulation mortar into the mold, allowing it to harden and dry, to obtain a sample block of aerogel composite cement insulation mortar: The density of the sample block is 230~270 kg / m3, and the method used is the volume-mass method; the compressive strength is 120~570 kPa, and the method used is the compression test method; the above tests require the temperature to be controlled at 21~25 ℃ and the relative humidity to be controlled at 40~60%.

[0035] In this embodiment, the density of the sample block is 230~270 kg / m3, the method used is the volumetric-mass method, and the test standard is GB / T 26000-2010; the compressive strength is 120~570 kPa, the method used is the compression test method, and the test standard is GB / T 26000-2010. The above tests require temperature control of 21~25 ℃ and relative humidity control of 40~60%.

[0036] Comparative Example 1 17.5 241±0.6 131 0.066 Comparative Example 2 20 225±0.6 127 0.049 Example 3 22.5 271±0.9 411 0.050 Example 4 25 247±1.0 166 0.046 Example 5 22.5 264±1.1 566 0.031 Example 6 22.5 264±1.0 566 0.031 Table 1 Mechanical and thermal insulation properties of thermal insulation mortar sample blocks First comparison example: Please refer to Figure 2 And Table 1, Figure 2 This is a physical image of the aerogel thermal insulation mortar sample block of the present invention.

[0037] Operating procedure: Add 145-150 parts of the quicklime, 15-20 parts of the white cement, and 30-35 parts of the redispersible latex powder to a mixer and stir for 3-5 minutes to obtain dry mortar. Pour the dry mortar into a bucket, add 90-140 parts of deionized water, and stir again for 2-6 minutes to obtain cement mortar. Then, use a scraper to evenly spread the cement mortar into a mold and let it stand at room temperature for 2-8 hours to allow the white cement to set initially. After hardening, send it to a forced-air drying oven at 20-60℃ to dry the product for 24-48 hours to obtain cement mortar sample blocks. The density test is 241 kg / m3, the compressive strength test is 131 kPa, and the thermal conductivity test is 0.066 W / (m·K).

[0038] Second comparison: Please refer to Figure 2 And Table 1, Figure 2 This is a physical image of the aerogel thermal insulation mortar sample block of the present invention.

[0039] Operating procedure: Add 142-147 parts of the quicklime, 14-19 parts of the white cement, and 38-43 parts of the redispersible latex powder to a mixer and stir for 3-5 minutes to obtain dry mortar. Take a portion of the total water from the designed mix and add 0.5-1.5 parts of KH550 to prepare the silane coupling agent solution. Sonicate the solution for 3-8 minutes, then add 20-60 parts of SiO2 aerogel particles to the solution for surface modification. Pour the aerogel particles and dry mortar into a bucket, add 90-140 parts of deionized water, and stir again for 2-6 minutes to obtain thermal insulation cement mortar. Apply the mortar evenly to a mold with a scraper and let it stand at room temperature for 2-8 hours for initial setting of the white cement. After hardening, place the product in a forced-air drying oven at 20-60℃ for 24-48 hours to dry, obtaining a sample block of thermal insulation cement mortar. The density test result is 225 kg / m3, and the compressive strength test result is 127. The thermal conductivity was measured to be 0.049 W / (m·K) at kPa.

[0040] Third embodiment: Please refer to Figure 2 And Table 1, Figure 2 This is a physical image of the aerogel thermal insulation mortar sample block of the present invention.

[0041] Operating procedure: Add 135-140 parts of the quicklime, 13-19 parts of white cement, 42-50 parts of the redispersible latex powder, 0.1-0.3 parts of calcium lignosulfonate, and 0.1-0.4 parts of hydroxypropyl methylcellulose to a mixer and mix for 3-7 minutes to obtain dry mortar; take a portion of the total water from the designed mix proportion and add 0.5-1.5 parts of KH550 to prepare a silane coupling agent solution, and ultrasonically treat for 3-8 minutes. Then, 20-60 parts of SiO2 aerogel particles were added to the above solution for surface modification. The aerogel particles and dry mortar were poured into a bucket, and 90-140 parts of deionized water were added. The mixture was stirred again for 2-6 minutes to obtain thermal insulation cement mortar. The mortar was then evenly applied to a mold with a scraper and left at room temperature for 2-8 hours for initial setting of the white cement. After hardening, the product was placed in a forced-air drying oven at 20-60℃ for 24-48 hours to obtain a sample block of thermal insulation cement mortar. The density test result was 271 kg / m3, the compressive strength test result was 411 kPa, and the thermal conductivity test result was 0.050 W / (m·K).

[0042] Fourth embodiment: Please refer to Figure 2 And Table 1, Figure 2 This is a physical image of the aerogel thermal insulation mortar sample block of the present invention.

[0043] Operating procedure: Add 130-135 parts quicklime, 13-19 parts white cement, 45-50 parts redispersible latex powder, 0.1-0.5 parts, 0.1-0.3 parts polycarboxylate superplasticizer, and 0.2-0.6 parts hydroxypropyl methylcellulose to a mixer and mix for 3-7 minutes to obtain dry mortar. Take a portion of the total water from the designed mix proportion and add 0.5-1.5 parts KH550 to prepare a silane coupling agent solution. Ultrasonically treat for 3-8 minutes. Then, 20-60 parts of SiO2 aerogel particles were added to the above solution for surface modification. The aerogel particles and dry mortar were poured into a bucket, and 100-150 parts of deionized water were added. The mixture was stirred again for 2-6 minutes to obtain thermal insulation cement mortar. The mortar was then evenly applied to a mold with a scraper and left at room temperature for 2-8 hours for initial setting of the white cement. After hardening, the product was placed in a forced-air drying oven at 20-60℃ for 24-48 hours to obtain a sample block of thermal insulation cement mortar. The density test result was 247 kg / m3, the compressive strength test result was 166 kPa, and the thermal conductivity test result was 0.046 W / (m·K).

[0044] Fifth embodiment: Please refer to Figure 2 And Table 1, Figure 2 This is a physical image of the aerogel thermal insulation mortar sample block of the present invention.

[0045] Operating procedure: Add 125-130 parts quicklime, 12-18 parts white cement, 42-50 parts redispersible latex powder, 10-20 parts silica fume, 0.1-0.5 parts polypropylene fiber, 0.1-0.3 parts polycarboxylate superplasticizer, and 0.2-0.6 parts hydroxypropyl methylcellulose to a mixer and mix for 3-7 minutes to obtain dry powder mortar; take a portion of the total water from the designed mix proportion and add 0.5-1.5 parts KH550 to prepare a silane coupling agent solution, and ultrasonically treat for 3-8 minutes. Then, 20-60 parts of SiO2 aerogel particles were added to the above solution for surface modification. The aerogel particles and dry mortar were poured into a bucket, and 100-150 parts of deionized water were added. The mixture was stirred again for 2-6 minutes to obtain thermal insulation cement mortar. The mortar was then evenly applied to a mold with a scraper and dried in a drying oven at a constant temperature of 10-30℃ for initial setting of the white cement. After hardening, the product was dried in a forced-air drying oven at 20-60℃ for 24-48 hours to obtain a sample block of thermal insulation cement mortar. The density test result was 264 kg / m3, the compressive strength test result was 566 kPa, and the thermal conductivity test result was 0.031 W / (m·K).

[0046] Sixth embodiment: Please refer to Figure 2 And Table 1, Figure 2 This is a physical image of the aerogel thermal insulation mortar sample block of the present invention.

[0047] Operating procedure: Add 120-125 parts quicklime, 25-35 parts white cement, 42-50 parts redispersible latex powder, 10-20 parts silica fume, 0.1-0.5 parts polypropylene fiber, 0.1-0.3 parts polycarboxylate superplasticizer, and 0.2-0.6 parts hydroxypropyl methylcellulose to a mixer and mix for 3-7 minutes to obtain dry mortar. Take a portion of the total water from the designed mix proportion and add 0.5-1.5 parts KH550 to prepare a silane coupling agent solution. Ultrasonically treat for 3-8 minutes. Then, 20-60 parts of SiO2 aerogel particles were added to the above solution for surface modification. The aerogel particles and dry mortar were poured into a bucket, and 100-150 parts of deionized water were added. The mixture was stirred again for 2-6 minutes to obtain thermal insulation cement mortar. The mortar was then evenly applied to a mold with a scraper and dried in a drying oven at a constant temperature of 10-30℃ for initial setting of the white cement. After hardening, the product was dried in a forced-air drying oven at 20-60℃ for 24-48 hours to obtain a sample block of thermal insulation cement mortar. The density test result was 264 kg / m3, the compressive strength test result was 566 kPa, and the thermal conductivity test result was 0.031 W / (m·K).

[0048] The comparative conclusions of the present invention based on the first comparative example, the second comparative example, the third embodiment, the fourth embodiment, the fifth embodiment, and the sixth embodiment are as follows: from Figure 1 As can be seen, Comparative Example 1 showed difficulty in particle dispersion during stirring, and cracked during demolding after drying, exhibiting low strength and crumbling easily upon touch. After surface modification with silane coupling agent, the other examples showed good particle dispersion during stirring, with the thermal insulation mortar powder evenly coating the particles, resulting in a dense and thick mortar (like thick yogurt), full volume, and easy spreading. After introducing HMPC and PP, the sample blocks showed no cracking after drying. Comparative Example 1 suffered severe damage during demolding, Comparative Example 2 experienced slight damage, and Example 3 also showed slight damage. Examples 4, 5, and 6 showed good overall molding condition after drying.

[0049] As shown in Table 1, the compatibility between cement mortar and aerogel particles is better after the addition of silane coupling agent. The aerogel can participate more effectively in the heat insulation process, resulting in a significant decrease in its thermal conductivity. Simultaneously, with the increase of latex content, the adhesion of the insulation mortar to the aerogel particles also increases, and the mechanical properties continuously improve, reaching a peak at a content of 22.5% and then declining. Compared to the unmodified sample, the sample block with the surface modified sample block can withstand a maximum compressive strength of 566 kPa after the addition of silica fume and latex powder content of approximately 22.5%, which is about 344% higher. KH550 dissolves in water and can undergo a hydrolysis reaction to generate -OH, which can chemically bond with the surface of aerogel particles, changing the interfacial state between the aerogel particle surface and the inorganic cementitious material, thereby improving the compatibility between aerogel particles and mortar. Therefore, the thermal conductivity of aerogel insulation mortar is basically maintained between 0.03-0.05 W / (m·K), and the thermal insulation performance is improved by about 24-53%.

[0050] The above-disclosed embodiments are merely one or more preferred embodiments of this application and should not be construed as limiting the scope of this application. Those skilled in the art can understand that all or part of the processes for implementing the above embodiments and equivalent changes made in accordance with the claims of this application still fall within the scope of this application.

Claims

1. A method for preparing SiO2 aerogel composite cement insulation mortar, characterized in that, Includes the following steps: A solution was formed by adding silane coupling agent and deionized water, and then SiO2 aerogel particles were added and stirred to obtain surface-modified SiO2 aerogel particles. Cement, quicklime, latex powder, admixtures, silica fume, and deionized water are added to a mixing mold to obtain a cementitious material. The SiO2 aerogel particles are added to the cementitious material, along with deionized water, a water-retaining agent for thickening, and a polycarboxylate superplasticizer, to obtain the white, viscous, granular cement insulation mortar. The cement insulation mortar is evenly applied to the mold using a scraper, and then hardened and dried to obtain a sample block of aerogel composite cement insulation mortar.

2. The method for preparing SiO2 aerogel composite cement insulation mortar as described in claim 1, characterized in that, In the step of adding a silane coupling agent and deionized water to form a solution, then adding SiO2 aerogel particles and stirring to obtain surface-modified SiO2 aerogel particles: The silane coupling agent is one or more of γ-aminopropyltriethoxysilane, dimethyldiethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane. The silane coupling agent and the deionized water are prepared into a solution with a mass fraction of 5-10%, and stirred at a speed of 400-600 rpm for 24-36 hours.

3. The method for preparing SiO2 aerogel composite cement insulation mortar as described in claim 2, characterized in that, In the step of adding cement, quicklime, latex powder, admixtures, silica fume, and deionized water into a mixing mold to obtain a cementitious material: The cement and the quicklime are mixed in a mass ratio of 1:6 to 10, and then the latex powder is added in a mass fraction of 15 to 30%, using deionized water as the solvent. The cement is one or both of white cement and gray cement, with a mesh size of 300 to 500. The quicklime is one or both of high-calcium quicklime, magnesium quicklime, and white jade quicklime. The latex powder is a copolymer of ethylene / vinyl acetate, a copolymer of vinyl acetate / ethylene tert-carbonate, or an acrylic acid copolymer powder. The mixing mold is used to stir at a low speed of 100 to 150 rpm for 3 to 6 minutes to obtain the cementitious material.

4. The method for preparing SiO2 aerogel composite cement insulation mortar as described in claim 3, characterized in that, In the step of adding cement, quicklime, latex powder, admixtures, silica fume, and deionized water into a mixing mold to obtain a cementitious material: The mass fraction of the silica fume is 10% to 20%, and the silica fume selected is one of ferrosilicon silica fume, industrial silicon silica fume, or alloy silica fume.

5. The method for preparing SiO2 aerogel composite cement insulation mortar as described in claim 4, characterized in that, In the step of adding the SiO2 aerogel particles to the cementitious material, and simultaneously adding deionized water, a water-retaining agent for thickening, and a polycarboxylate-based water-reducing agent to obtain the white, viscous, granular cement insulation mortar: The water-reducing agent has a mass fraction of 0.5-0.9%, and the selected water-reducing agent is one of lignin-based water-reducing agents, aminosulfonate-based water-reducing agents, or polycarboxylate-based water-reducing agents.

6. The method for preparing SiO2 aerogel composite cement insulation mortar as described in claim 4, characterized in that, In the step of adding the SiO2 aerogel particles to the cementitious material, and simultaneously adding deionized water, a water-retaining agent for thickening, and a polycarboxylate-based water-reducing agent to obtain the white, viscous, granular cement insulation mortar: The water-retaining agent has a mass fraction of 0.12~0.4%, and the selected water-retaining agent is one of methylcellulose, hydroxypropyl methylcellulose or hydroxyethyl methylcellulose.

7. The method for preparing SiO2 aerogel composite cement insulation mortar as described in claim 6, characterized in that, In the step of adding a silane coupling agent and deionized water to form a solution, then adding SiO2 aerogel particles and stirring to obtain surface-modified SiO2 aerogel particles: The SiO2 aerogel particles have a density of 60-120 kg / m³, measured using the volume-mass method; a particle size of 0.2-5 mm, measured using laser diffraction; and a hydrophobicity of 60-99%, measured using the hydrophobicity method. The thermal conductivity is 0.013~0.02 W / m·K, and the method used is the plate heat flow meter method; the compressive strength is 100-500 kPa, and the method used is the compression test method. The above tests require the temperature to be controlled at 21~25℃ and the relative humidity to be controlled at 40~60%.

8. The method for preparing SiO2 aerogel composite cement insulation mortar as described in claim 7, characterized in that, In the step of using a scraper to evenly apply the cement insulation mortar into a mold, allowing it to harden and dry, and obtaining a sample block of aerogel composite cement insulation mortar: The density of the sample block is 230~270 kg / m3, and the method used is the volume-mass method; the compressive strength is 120~570 kPa, and the method used is the compression test method; the above tests require the temperature to be controlled at 21~25 ℃ and the relative humidity to be controlled at 40~60%.

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