Thermal insulation brick based on cement mixture and preparation method of thermal insulation brick

Abstract

The invention discloses a thermal insulation brick based on a cement mixture and a preparation method thereof, and belongs to the technical field of building material processing, the thermal insulation brick comprises the following components by weight: 60-70 parts of PEG modified aggregate, 20-25 parts of modified silica, 8-12 parts of silicon-based fiber powder, 30-50 parts of cement, 6-7 parts of an additive, and 30-40 parts of a foaming liquid, pEG modified aggregate, modified silicon dioxide, silicon-based fiber powder and cement are mixed to form cement slurry, then the cement slurry is mixed with foaming foam, after the foaming foam is promoted to be evenly dispersed in the cement slurry, brick molding and curing are conducted, the heat insulation performance and compressive strength of the heat preservation brick are effectively improved, the heat preservation brick has good energy storage performance, and the service life of the heat preservation brick is prolonged. The thermal insulation performance of the thermal insulation brick is further improved.

Description

Technical Field

[0001] The invention relates to the technical field of building material processing, and in particular to a thermal insulation brick based on a cement mixture and a preparation method thereof. Background Art

[0002] With the increasing requirements of energy conservation, environmental protection and sustainable development, in the construction industry, traditional solid bricks are difficult to meet the needs of modern buildings due to their heavy weight and poor thermal insulation performance. Insulation bricks are a new type of building material synthesized from polymer materials or other inorganic non-metallic materials. They have low thermal conductivity and good thermal insulation effect, which can effectively reduce heat transfer and improve the thermal insulation performance of buildings.

[0003] The cement foam brick in the prior art is a new type of building material made of cement as raw material, combined with an appropriate amount of foaming agent and auxiliary materials. It has gradually occupied a place in the construction industry with its multi-functional, environmentally friendly and high-strength characteristics. The thermal insulation performance of the insulation brick is closely related to the uniformity of its internal pore distribution and the porosity. The more uniform the pore distribution of the insulation brick and the higher the porosity, the better its thermal insulation performance. Conversely, the worse its thermal insulation performance is. In the preparation process of traditional insulation bricks, due to the poor wettability and dispersibility of the aggregate itself, inorganic particles are prone to agglomeration, and the bonding force between the particles and the cement matrix is ​​poor, resulting in the need to further improve the mechanical compressive strength of the insulation brick. In addition, the low dispersibility of traditional concrete materials will reduce the stability of the foam in the cement mixture, making it difficult for the foam to be evenly dispersed and stably present in the foaming slurry. The thermal insulation performance and compressive strength of the insulation brick material need to be further improved. Summary of the invention

[0004] The object of the present invention is to provide a thermal insulation brick based on a cement mixture and a preparation method thereof, so as to solve the technical problem in the prior art that the thermal insulation performance and compressive strength of the thermal insulation brick material need to be further improved.

[0005] The object of the present invention can be achieved by the following technical scheme: a thermal insulation brick based on cement mixture, comprising the following components in parts by weight: 60-70 parts of PEG modified aggregate, 20-25 parts of modified silica, 8-12 parts of silicon-based fiber powder, 30-50 parts of cement, 6-7 parts of additives, 30-40 parts of foaming liquid and 50-60 parts of drinking water; The preparation method of PEG modified aggregate is as follows: aggregate and drinking water are mixed and stirred, siloxane modified PEG is added to the mixed system, the temperature of the reaction system is increased to 60-70°C, the mixture is stirred for 4-6 hours, and post-processed to obtain PEG modified aggregate.

[0006] The synthetic reaction mechanism of PEG modified aggregate is: During the reaction, the triethoxysilane molecules on the siloxane-modified PEG molecules are hydrolyzed in a water environment to form silanols and bonded to the surface of the aggregate particles, forming PEG modification on the aggregate particles to prepare PEG-modified aggregates.

[0007] Further, the aggregate is composed of river sand, mullite powder, slag powder, and fly ash in a weight ratio of 15-17:6-7:5-7:8-10; The additives are composed of a water reducing agent, a foam stabilizer, an air entraining agent and an early strength agent in a weight ratio of 5:3:2:2; The foaming liquid is composed of 2-acrylamide-2-methylpropanesulfonic acid, N,N'-methylenebisacrylamide, sodium dodecylbenzenesulfonate, ammonium persulfate and drinking water in a dosage ratio of 2g:1.2g:1g:0.2g:40mL.

[0008] Furthermore, the dosage ratio of the aggregate, drinking water and siloxane-modified PEG is 5g:20mL:2g, and the post-treatment includes: after the reaction is completed, the temperature of the reaction system is lowered to room temperature, filtered, the filter cake is washed twice with drinking water and then dried, the filter cake is transferred to a drying oven at a temperature of 60-70°C, and dried to constant weight to obtain PEG-modified aggregate.

[0009] Furthermore, the preparation method of the siloxane-modified PEG is as follows: under the protection of inert gas, PEG and tetrahydrofuran are mixed and stirred, the temperature of the reaction system is increased to 40-50° C., isocyanatepropyltriethoxysilane is added to the reaction system, the reaction is kept warm for 2-3 hours, and post-processed to obtain the siloxane-modified PEG.

[0010] The synthetic reaction mechanism of siloxane-modified PEG is: During the reaction, the hydroxyl group on the PEG molecule undergoes a condensation reaction with the isocyanate group on the isocyanatepropyltriethoxysilane molecule to form a triethoxysilane modification on the PEG molecular chain, thereby preparing a siloxane-modified PEG.

[0011] Furthermore, the usage ratio of the PEG, tetrahydrofuran and isocyanatepropyltriethoxysilane is 7g:40mL:3g, the PEG is PEG-800, and the post-treatment includes: after the reaction is completed, the temperature of the reaction system is increased to 60°C, and the low-boiling substances are removed under reduced pressure to obtain siloxane-modified PEG.

[0012] Furthermore, the preparation method of the modified silica is: lauric acid, dodecanol and anhydrous ethanol are mixed and stirred until the system is dissolved, fumed silica is added to the reaction system, stirred and dispersed for 60-80 minutes at room temperature, the dispersion liquid is added to the reaction system, stirred and maintained at temperature for 30-50 minutes, and post-treated to obtain modified silica.

[0013] The synthetic reaction mechanism of modified silica is: Ethanol is a good organic solvent, which helps to dissolve lauric acid and dodecanol, so that lauric acid and dodecanol form a uniform dispersion in anhydrous ethanol. Fumed silica is added to the reaction system. Under the action of stirring, the fumed silica particles are gradually dispersed in the mixed solution of ethanol / lauric acid / dodecanol to form a uniform dispersion system. Then an aqueous dispersion is added to the reaction system. The aqueous dispersion, as a poor solvent, promotes the precipitation of lauric acid and dodecanol from ethanol and covers the outside of the fumed silica, and precipitates from the solution in the form of co-precipitation to prepare modified silica.

[0014] Furthermore, the dosage ratio of the lauric acid, dodecanol, anhydrous ethanol, fumed silica and dispersion is 3g:2g:20mL:5g:40mL, the dispersion is composed of polyethylene glycol 400 and deionized water at a ratio of 2-3g:100mL, and the post-treatment includes: after the reaction is completed, the temperature of the reaction system is lowered to 10-15°C, filtered, the filter cake is washed with deionized water 3 times and then dried, and the filter cake is naturally dried to obtain modified silica.

[0015] Furthermore, the silicon-based fiber powder is obtained by processing the following steps: A1. Mix and stir the chopped glass fibers and the activation solution, raise the temperature of the reaction system to 60-80°C, keep the reaction warm for 2-3 hours, and perform post-treatment to obtain activated fibers; A2. Stir and mix the activated fiber, methyl triethoxysilane, ethyl orthosilicate, 3-glycidyloxypropyl triethoxysilane and anhydrous ethanol, lower the temperature of the reaction system to 10-15°C, add hydrochloric acid solution to the reaction system, keep the reaction warm for 3-5 hours, and post-treat to obtain silicon-based fiber powder.

[0016] The synthetic reaction mechanism of silicon-based fiber powder is: Sodium hydroxide, as a strong base, can promote the decomposition of hydrogen peroxide to produce oxidizing free radicals. During the reaction, the silicate structure on the surface of the glass fiber is oxidized or etched by the free radicals in the activation solution, increasing the roughness and active sites on the surface of the chopped glass fiber. Methyltriethoxysilane, ethyl orthosilicate, and 3-glycidyloxypropyltriethoxysilane contain ethoxysilyl bonds on their molecules. Under the condition of acid as a catalyst, the ethoxysilyl group decomposes to form silanol groups. The silanol groups react with each other or with the active reaction sites on the surface of the activated fiber to form silicon-oxygen-silicon bonds, forming a polysiloxane coating containing epoxy groups on the outside of the fiber to prepare silicon-based fiber powder.

[0017] Furthermore, in step A1, the ratio of the chopped glass fiber to the activation solution is 1g:5-6mL, the activation solution is composed of 3-5wt% sodium hydroxide solution and 20wt% hydrogen peroxide in a volume ratio of 5:1, and the post-treatment includes: after the reaction is completed, the temperature of the reaction system is lowered to room temperature, filtered, the filter cake is washed with drinking water until it is neutral and then dried, the filter cake is transferred to a drying oven with a temperature of 60-70°C, and vacuum dried to constant weight to obtain activated fiber.

[0018] Furthermore, in step A2, the amount ratio of the activated fiber, methyltriethoxysilane, ethyl orthosilicate, 3-glycidyloxypropyltriethoxysilane, anhydrous ethanol and hydrochloric acid solution is 30g:10-12g:8-10g:4-6g:60mL:10mL, the concentration of the hydrochloric acid solution is 0.8-1.2mol / L, and the post-treatment includes: after the reaction is completed, adding ammonia water to the reaction system, adjusting the pH of the system to 7, raising the temperature of the reaction system to 60-70°C, and removing low-boiling substances under reduced pressure to obtain a wet gel, and evenly spreading the wet gel in a drying oven at a temperature of 110-120°C, drying to constant weight, and crushing to obtain a silicon-based fiber powder.

[0019] The present invention also provides a method for preparing a thermal insulation brick based on a cement mixture, comprising the following steps: S1, adding the foaming liquid into a foaming machine for foaming to prepare foamed foam; S2, adding PEG modified aggregate, cement, silicon-based fiber powder, modified silica, and additives into a mixer and stirring for 3-5 minutes, adding drinking water into the mixer, stirring and mixing for 8-10 minutes, and then adding foaming foam into the mixer, stirring and dispersing for 1-2 minutes to obtain a foaming slurry; S3, pour the foaming slurry into several molds respectively, then scrape the slurry on the upper surface of the mold flat and seal the mold, let it stand for 4-6 hours, demold, and obtain the insulation brick blank; S4, placing the thermal insulation brick blanks in a curing room and curing them for 7 days to obtain thermal insulation bricks.

[0020] The present invention has the following beneficial effects: 1. The present invention is to form aggregates by river sand, mullite powder, slag powder and fly ash. Under the action of cement, the inorganic particles of the aggregate are interconnected by physical and chemical bonding to form a certain strength foundation. The present application modifies the aggregate by siloxane-modified PEG, and grafts PEG to the aggregate surface by triethoxysilane. PEG, as a non-ionic surfactant, has good wettability and dispersibility. During the material preparation process, PEG can effectively reduce the surface tension of aggregate particles, promote uniform dispersion between particles, reduce agglomeration between particles, enhance the interface bonding force between aggregate and cement matrix, reduce microcrack expansion, and enhance the mechanical strength of thermal insulation bricks. Moreover, by promoting uniform dispersion of aggregates through PEG, a more uniform and fine pore structure can be formed in the material, the porosity in the thermal insulation brick is increased, and its thermal insulation performance is improved.

[0021] 2. The present invention uses chopped glass fibers as raw materials, and adopts polysiloxane to coat and modify the chopped glass fibers, thereby increasing the interfacial bonding force between the glass fibers and the matrix, and at the same time improving the strength of the fibers themselves, thereby indirectly enhancing the compressive strength of the foamed insulation bricks. The gas-phase silica is modified by lauric acid and dodecyl alcohol, two organic substances with longer molecular chains, to give the modified silica particles flexibility and mechanical strength, so that the silica particles can better absorb and disperse stress when subjected to external forces, and the mechanical strength ensures that the particles themselves are not easy to break, thereby effectively improving the overall performance of the material. In addition, lauric acid, dodecyl alcohol and PEG-800 can absorb and release heat within a certain temperature range, reduce the impact of external temperature fluctuations on indoor temperature, make the indoor temperature more stable, and reduce carbon emissions.

[0022] 3. The present invention comprises 2-acrylamide-2-methylpropanesulfonic acid, N,N'-methylenebisacrylamide, sodium dodecylbenzenesulfonate, ammonium persulfate and drinking water to form a foaming liquid. The 2-acrylamide-2-methylpropanesulfonic acid in the foaming liquid serves as a surfactant, which can reduce the surface tension of water and help form stable and fine foam. N,N'-methylenebisacrylamide serves as a cross-linking agent, which can enhance the stability of the foam. Sodium dodecylbenzenesulfonate serves as an anionic surfactant, which can also stabilize the foam. Ammonium persulfate serves as an initiator, which can initiate the reaction of 2-acrylamide-2-methylpropanesulfonic acid and N,N'-methylenebisacrylamide. N'-methylenebisacrylamide is polymerized to form a polymer network with a certain viscosity, ensuring the formation of a uniform and delicate foam structure in the foaming slurry. The long-chain fatty acid structure modified on the modified silica particles helps to form a tighter foam structure and reduce the interconnection between bubbles, thereby improving the compressive strength and stability of the foam. Modification of the aggregate by PEG can reduce the surface tension of the aggregate and improve its surface wettability, so that the aggregate and the foaming foam are evenly mixed during the stirring process, thereby improving the dispersibility of the foam in the foaming slurry and improving the thermal insulation performance and mechanical compressive strength of the insulation brick. DETAILED DESCRIPTION

[0023] 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.

[0024] In this application, the mesh size of river sand is 8-16 mesh; In the present application, cement is Portland cement; In this application, the foam stabilizer is selected from Jining Fangyu Chemical Co., Ltd., the product name is cement foaming stabilizer, the model is DX560, it is a light yellow transparent liquid with a density of 1.00g / cm 3 ; In this application, the air entraining agent is selected from Nanjing Chuhai New Material Technology Co., Ltd., model CHUPOL AE-503, solid content of 31.4-34.6%, density of 1.03-1.07g / cm 3 ; In this application, the early strength agent is selected from Qidong Rongsheng Chemical Co., Ltd., the product name is calcium formate, the active ingredient content is 98%, and the density is 200g / cm 3 . Example 1

[0025] This embodiment provides a method for preparing a thermal insulation brick based on a cement mixture, comprising the following steps: S1. Preparation of PEG-modified aggregate Weigh: 700 g of PEG-800 and 4000 mL of tetrahydrofuran are added to a nitrogen-protected reactor and stirred. The temperature of the reactor is raised to 40° C. 300 g of isocyanatepropyltriethoxysilane is added to the reactor and the reaction is carried out for 2 h. The temperature of the reaction system is raised to 60° C. Low-boiling substances are removed under reduced pressure to obtain siloxane-modified PEG; Mix river sand, mullite powder, slag powder and fly ash in a weight ratio of 15:6:5:8 to obtain aggregate for later use; Weigh: 500 g of aggregate and 2000 mL of drinking water, add into a stirring tank and stir for 30 min, add 200 g of siloxane-modified PEG into the stirring tank, raise the temperature of the stirring tank to 60°C, keep warm and stir for 4 h, post-treat, lower the temperature of the stirring tank to room temperature, filter, wash the filter cake twice with drinking water and then drain, transfer the filter cake to a drying oven at 60°C, dry to constant weight, and obtain PEG-modified aggregate.

[0026] S2. Preparation of modified silicon dioxide Mix polyethylene glycol 400 and deionized water at a ratio of 2 g:100 mL to obtain a dispersion for later use; Weigh: 300 g of lauric acid, 200 g of dodecanol and 2000 mL of anhydrous ethanol, add to a reactor and stir until the system is dissolved, add 500 g of fumed silica to the reactor, stir and disperse for 60 min at room temperature, add 4000 mL of dispersion to the reactor, keep warm and stir for 30 min, lower the temperature of the reaction system to 10°C, filter, wash the filter cake with deionized water 3 times and then dry it, and air-dry the filter cake to obtain modified silica.

[0027] S3. Preparation of silicon-based fiber powder 3 wt % sodium hydroxide solution and 20 wt % hydrogen peroxide were mixed uniformly in a volume ratio of 5:1 to obtain an activation solution for later use; Weigh: 100 g of chopped glass fiber and 500 mL of activation solution, add them into a reactor and stir, raise the temperature of the reactor to 60°C, keep the temperature for 2 hours, lower the temperature of the reactor to room temperature, filter, wash the filter cake with drinking water until it is neutral and then dry, transfer the filter cake to a drying oven at 60°C, vacuum dry to constant weight, and obtain activated fiber; Weigh: 90g of activated fiber, 30g of methyltriethoxysilane, 24g of ethyl orthosilicate, 12g of 3-glycidyloxypropyltriethoxysilane, and 180mL of anhydrous ethanol, add into a reactor and stir, lower the temperature of the reactor to 10°C, add 30mL of 0.8mol / L hydrochloric acid solution into the reactor, keep warm and react for 3h, add ammonia water into the reactor, adjust the pH of the system to 7, raise the temperature of the reactor to 60°C, evaporate low boiling points under reduced pressure to obtain wet gel, spread the wet gel evenly in a drying oven at a temperature of 110°C, dry to constant weight, and grind to obtain silicon-based fiber powder.

[0028] S4. Preparation of foaming liquid 2-Acrylamide-2-methylpropanesulfonic acid, N,N'-methylenebisacrylamide, sodium dodecylbenzenesulfonate, ammonium persulfate and drinking water were added into a reactor in a dosage ratio of 2g:1.2g:1g:0.2g:40mL and mixed and stirred. The temperature of the reactor was raised to 70°C, kept warm for reaction for 3h, and naturally cooled to room temperature to obtain a foaming liquid.

[0029] S5. Preparation of thermal insulation bricks The polycarboxylate water reducer, foam stabilizer, air entraining agent and early strength agent are uniformly mixed in a weight ratio of 5:3:2:2 to obtain an additive for standby use; Weigh out by weight: 60 parts of PEG modified aggregate, 20 parts of modified silica, 8 parts of silicon-based fiber powder, 30 parts of cement, 6 parts of additives, 30 parts of foaming liquid and 50 parts of drinking water for later use; The foaming liquid is placed in a foaming machine and foamed with carbon dioxide as the gas source to obtain a density of 60kg / m 3 of foaming foam, set aside; Add PEG modified aggregate, cement, silicon-based fiber powder, modified silica, and additives into a mixer and stir for 3 minutes, add drinking water into the mixer and stir and mix for 8 minutes, then add foaming foam into the mixer and stir and disperse for 1 minute to obtain a foaming slurry; Pour the foamed slurry into several molds respectively, then scrape the slurry on the upper surface of the mold flat and seal the mold, let it stand for 4 hours, demould, and obtain the thermal insulation brick blank; The thermal insulation brick blanks were placed in a curing room at a temperature of 20°C and a humidity of 80% for curing for 7 days to obtain thermal insulation bricks. Example 2

[0030] This embodiment provides a method for preparing a thermal insulation brick based on a cement mixture, comprising the following steps: S1. Preparation of PEG-modified aggregate Weigh: 700 g of PEG-800 and 4000 mL of tetrahydrofuran are added to a nitrogen-protected reactor and stirred. The temperature of the reactor is raised to 45°C. 300 g of isocyanatepropyltriethoxysilane is added to the reactor. The reaction is kept warm for 2.5 hours. The temperature of the reaction system is raised to 60°C. Low-boiling substances are removed under reduced pressure to obtain siloxane-modified PEG. Mix river sand, mullite powder, slag powder and fly ash in a weight ratio of 16:6.5:6:9 to obtain aggregate for later use; Weigh: 500 g of aggregate and 2000 mL of drinking water, add into a stirring tank and stir for 40 min, add 200 g of siloxane-modified PEG into the stirring tank, raise the temperature of the stirring tank to 65°C, keep warm and stir for 5 h, post-treat, lower the temperature of the stirring tank to room temperature, filter, wash the filter cake twice with drinking water and then dry, transfer the filter cake to a drying oven at 65°C, dry to constant weight, and obtain PEG-modified aggregate.

[0031] S2. Preparation of modified silicon dioxide Mix polyethylene glycol 400 and deionized water at a ratio of 2.5 g:100 mL to obtain a dispersion for later use; Weigh: 300 g of lauric acid, 200 g of dodecanol and 2000 mL of anhydrous ethanol, add to a reactor and stir until the system is dissolved, add 500 g of fumed silica to the reactor, stir and disperse for 70 min at room temperature, add 4000 mL of dispersion to the reactor, keep warm and stir for 40 min, lower the temperature of the reaction system to 13°C, filter, wash the filter cake with deionized water 3 times and then dry it, and air-dry the filter cake to obtain modified silica.

[0032] S3. Preparation of silicon-based fiber powder 4 wt % sodium hydroxide solution and 20 wt % hydrogen peroxide were mixed uniformly in a volume ratio of 5:1 to obtain an activation solution for later use; Weigh: 100 g of chopped glass fiber and 550 mL of activation solution, add them into a reactor and stir, raise the temperature of the reactor to 70°C, keep the temperature for 2.5 hours, lower the temperature of the reactor to room temperature, filter, wash the filter cake with drinking water until it is neutral and then dry, transfer the filter cake to a drying oven at 65°C, vacuum dry to constant weight, and obtain activated fiber; Weigh: 90g of activated fiber, 33g of methyltriethoxysilane, 27g of ethyl orthosilicate, 16g of 3-glycidyloxypropyltriethoxysilane, and 180mL of anhydrous ethanol, add into a reactor and stir, lower the temperature of the reactor to 13°C, add 30mL of 1.0mol / L hydrochloric acid solution into the reactor, keep warm and react for 4h, add ammonia water into the reactor, adjust the pH of the system to 7, raise the temperature of the reactor to 65°C, evaporate low boiling points under reduced pressure to obtain wet gel, spread the wet gel evenly in a drying oven at a temperature of 115°C, dry to constant weight, and grind to obtain silicon-based fiber powder.

[0033] S4. Preparation of foaming liquid 2-Acrylamide-2-methylpropanesulfonic acid, N,N'-methylenebisacrylamide, sodium dodecylbenzenesulfonate, ammonium persulfate and drinking water were added into a reactor in a dosage ratio of 2g:1.2g:1g:0.2g:40mL and mixed and stirred. The temperature of the reactor was raised to 75°C, kept warm for reaction for 2.5h, and naturally cooled to room temperature to obtain a foaming liquid.

[0034] S5. Preparation of thermal insulation bricks The polycarboxylate water reducer, foam stabilizer, air entraining agent and early strength agent are uniformly mixed in a weight ratio of 5:3:2:2 to obtain an additive for standby use; Weigh out by weight: 65 parts of PEG modified aggregate, 23 parts of modified silica, 10 parts of silicon-based fiber powder, 40 parts of cement, 6.5 parts of additives, 35 parts of foaming liquid and 55 parts of drinking water for later use; The foaming liquid is placed in a foaming machine and foamed with carbon dioxide as the gas source to obtain a density of 65kg / m 3 of foaming foam, set aside; Add PEG modified aggregate, cement, silicon-based fiber powder, modified silica, and additives into a mixer and stir for 4 minutes, add drinking water into the mixer and stir and mix for 9 minutes, then add foaming foam into the mixer and stir and disperse for 1.5 minutes to obtain a foaming slurry; Pour the foamed slurry into several molds respectively, then scrape the slurry on the upper surface of the mold flat and seal the mold, let it stand for 5 hours, demould, and obtain the insulation brick blank; The thermal insulation brick blanks were placed in a curing room at a temperature of 23°C and a humidity of 85% for 7 days to obtain thermal insulation bricks. Example 3

[0035] This embodiment provides a method for preparing a thermal insulation brick based on a cement mixture, comprising the following steps: S1. Preparation of PEG-modified aggregate Weigh: 700 g of PEG-800 and 4000 mL of tetrahydrofuran are added to a nitrogen-protected reactor and stirred. The temperature of the reactor is raised to 50° C. 300 g of isocyanatepropyltriethoxysilane is added to the reactor and the reaction is carried out for 3 h. The temperature of the reaction system is raised to 60° C. Low-boiling substances are removed under reduced pressure to obtain siloxane-modified PEG; Mix river sand, mullite powder, slag powder and fly ash in a weight ratio of 17:7:7:10 to obtain aggregate for later use; Weigh: 500 g of aggregate and 2000 mL of drinking water are added to a stirring tank and stirred for 50 min. 200 g of siloxane-modified PEG is added to the stirring tank. The temperature of the stirring tank is increased to 70°C and stirred for 6 h. After post-treatment, the temperature of the stirring tank is lowered to room temperature and filtered. The filter cake is washed twice with drinking water and then dried. The filter cake is transferred to a drying oven at 70°C and dried to constant weight to obtain PEG-modified aggregate.

[0036] S2. Preparation of modified silicon dioxide Mix polyethylene glycol 400 and deionized water at a ratio of 3 g:100 mL to obtain a dispersion for later use; Weigh: 300 g of lauric acid, 200 g of dodecanol and 2000 mL of anhydrous ethanol, add to a reactor and stir until the system is dissolved, add 500 g of fumed silica to the reactor, stir and disperse for 80 min at room temperature, add 4000 mL of dispersion to the reactor, keep warm and stir for 50 min, lower the temperature of the reaction system to 15°C, filter, wash the filter cake with deionized water 3 times and then dry it, and air-dry the filter cake to obtain modified silica.

[0037] S3. Preparation of silicon-based fiber powder 5 wt % sodium hydroxide solution and 20 wt % hydrogen peroxide were mixed uniformly in a volume ratio of 5:1 to obtain an activation solution for later use; Weigh: 100 g of chopped glass fiber and 600 mL of activation solution, add them into a reactor and stir, raise the temperature of the reactor to 80°C, keep the temperature for 3 hours, lower the temperature of the reactor to room temperature, filter, wash the filter cake with drinking water until it is neutral and then dry, transfer the filter cake to a drying oven at 70°C, vacuum dry to constant weight, and obtain activated fiber; Weigh: 90g of activated fiber, 36g of methyltriethoxysilane, 30g of ethyl orthosilicate, 18g of 3-glycidyloxypropyltriethoxysilane, and 180mL of anhydrous ethanol, add into a reactor and stir, lower the temperature of the reactor to 15°C, add 30mL of 1.2mol / L hydrochloric acid solution into the reactor, keep warm and react for 5h, add ammonia water into the reactor, adjust the pH of the system to 7, raise the temperature of the reactor to 70°C, evaporate low boiling points under reduced pressure to obtain wet gel, spread the wet gel evenly in a drying oven at a temperature of 120°C, dry to constant weight, and grind to obtain silicon-based fiber powder.

[0038] S4. Preparation of foaming liquid 2-Acrylamide-2-methylpropanesulfonic acid, N,N'-methylenebisacrylamide, sodium dodecylbenzenesulfonate, ammonium persulfate and drinking water were added into a reactor in a dosage ratio of 2g:1.2g:1g:0.2g:40mL and mixed and stirred. The temperature of the reactor was raised to 80°C, kept warm for 2h, and naturally cooled to room temperature to obtain a foaming liquid.

[0039] S5. Preparation of thermal insulation bricks The polycarboxylate water reducer, foam stabilizer, air entraining agent and early strength agent are uniformly mixed in a weight ratio of 5:3:2:2 to obtain an additive for standby use; Weigh by weight: 70 parts of PEG modified aggregate, 25 parts of modified silica, 12 parts of silicon-based fiber powder, 50 parts of cement, 7 parts of additives, 40 parts of foaming liquid and 60 parts of drinking water for later use; The foaming liquid is placed in a foaming machine and foamed with carbon dioxide as the gas source to obtain a density of 70kg / m 3 of foaming foam, set aside; Add PEG modified aggregate, cement, silicon-based fiber powder, modified silica, and additives into a mixer and stir for 5 minutes, add drinking water into the mixer and stir and mix for 10 minutes, then add foaming foam into the mixer and stir and disperse for 2 minutes to obtain a foaming slurry; Pour the foamed slurry into several molds respectively, then scrape the slurry on the upper surface of the mold flat and seal the mold, let it stand for 6 hours, demould, and obtain the thermal insulation brick blank; The thermal insulation brick blanks were placed in a curing room at a temperature of 26°C and a humidity of 90% for 7 days to obtain thermal insulation bricks.

[0040] Comparative Example 1 The difference between this comparative example and Example 3 is that the aggregate in step S1 is used to replace the PEG modified aggregate in step S5.

[0041] Comparative Example 2 The difference between this comparative example and Example 3 is that lauric acid is not added in step S2.

[0042] Comparative Example 3 The difference between this comparative example and Example 3 is that the silicon-based fiber powder in step S5 is replaced by the activated fiber in step S3.

[0043] Comparative Example 4 The difference between this comparative example and Example 3 is that ammonium persulfate is not added in step S4.

[0044] Performance Test: Five insulation brick samples prepared in Examples 1-3 and Comparative Examples 1-4 were selected as test samples, and the compressive strength and thermal conductivity of the insulation brick test samples prepared in Examples 1-3 and Comparative Examples 1-4 were measured with reference to the standard GB / T 29060-2012 "Composite insulation bricks and composite insulation blocks", and the average values ​​were calculated; Five insulation brick samples prepared in Examples 1-3 and Comparative Examples 1-4 were selected as test samples. The phase change latent heat of the insulation brick test samples prepared in Examples 1-3 and Comparative Examples 1-4 was measured with reference to the standard JC / T 2111-2012 "Test Method for Phase Change Temperature Regulation Performance of Building Materials", and the average value was calculated. The specific test results are shown in Table 1 below.

[0045] Table 1-Performance test data of samples

[0046] Data Analysis: A comparative analysis of the data in Table 1 above shows that the compressive strength of the insulation bricks prepared by the present invention reaches 18.41 MPa, the thermal conductivity is reduced to 0.1896 W / (m·k), the latent heat of phase change reaches 216.51 J / g, and the performance test data are all better than those of the comparative example. The present invention is to modify the aggregate by PEG and then mix it with modified silica, silicon-based fiber powder and cement to form a cement slurry, and then mix it by foaming foam to promote the uniform dispersion of the foaming foam in the cement slurry to prepare the foaming slurry, and then cure it after molding the bricks, which not only effectively improves the thermal insulation performance and compressive strength of the insulation bricks, but also makes the insulation bricks have good energy storage performance, thereby further improving the thermal insulation performance of the insulation bricks.

[0047] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. 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 understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A thermal insulation brick based on cement mixture, characterized in that: The invention comprises the following components in parts by weight: 60-70 parts of PEG modified aggregate, 20-25 parts of modified silicon dioxide, 8-12 parts of silicon-based fiber powder, 30-50 parts of cement, 6-7 parts of additives, 30-40 parts of foaming liquid and 50-60 parts of drinking water; The preparation method of PEG modified aggregate is as follows: aggregate and drinking water are mixed and stirred, siloxane modified PEG is added to the mixed system, the temperature of the reaction system is increased to 60-70°C, the mixture is stirred for 4-6 hours, and post-processed to obtain PEG modified aggregate.

2. The thermal insulation brick based on cement mixture according to claim 1, characterized in that: The aggregate is composed of river sand, mullite powder, slag powder and fly ash in a weight ratio of 15-17:6-7:5-7:8-10; The additives are composed of a water reducing agent, a foam stabilizer, an air entraining agent and an early strength agent in a weight ratio of 5:3:2:2; The foaming liquid is composed of 2-acrylamide-2-methylpropanesulfonic acid, N,N'-methylenebisacrylamide, sodium dodecylbenzenesulfonate, ammonium persulfate and drinking water in a dosage ratio of 2g:1.2g:1g:0.2g:40mL.

3. The thermal insulation brick based on cement mixture according to claim 1, characterized in that: The dosage ratio of the aggregate, drinking water and siloxane-modified PEG is 5g:20mL:2g. The post-treatment includes: after the reaction is completed, the temperature of the reaction system is lowered to room temperature, filtered, the filter cake is washed twice with drinking water and then dried, the filter cake is transferred to a drying oven at a temperature of 60-70°C, and dried to constant weight to obtain PEG-modified aggregate.

4. The thermal insulation brick based on cement mixture according to claim 1, characterized in that: The preparation method of the siloxane-modified PEG is as follows: under the protection of inert gas, PEG and tetrahydrofuran are mixed and stirred, the temperature of the reaction system is increased to 40-50° C., isocyanatepropyltriethoxysilane is added to the reaction system, the reaction is kept warm for 2-3 hours, and the siloxane-modified PEG is obtained by post-treatment.

5. The thermal insulation brick based on cement mixture according to claim 1, characterized in that: The dosage ratio of the PEG, tetrahydrofuran and isocyanatepropyltriethoxysilane is 7g:40mL:3g, the PEG is PEG-800, and the post-treatment comprises: after the reaction is completed, the temperature of the reaction system is increased to 60°C, and the low-boiling substances are removed under reduced pressure to obtain siloxane-modified PEG.

6. The thermal insulation brick based on cement mixture according to claim 1, characterized in that: The preparation method of the modified silicon dioxide is as follows: lauric acid, dodecanol and anhydrous ethanol are mixed and stirred until the system is dissolved, fumed silicon dioxide is added to the reaction system, stirred and dispersed for 60-80 minutes at room temperature, dispersion liquid is added to the reaction system, stirred and maintained at temperature for 30-50 minutes, and post-processed to obtain modified silicon dioxide.

7. The thermal insulation brick based on cement mixture according to claim 6, characterized in that: The dosage ratio of the lauric acid, dodecanol, anhydrous ethanol, fumed silica and dispersion is 3g:2g:20mL:5g:40mL, the dispersion is composed of polyethylene glycol 400 and deionized water in a ratio of 2-3g:100mL, and the post-treatment comprises: after the reaction is completed, the temperature of the reaction system is lowered to 10-15°C, filtered, the filter cake is washed with deionized water for 3 times and then dried, and the filter cake is naturally dried to obtain modified silica.

8. The thermal insulation brick based on cement mixture according to claim 1, characterized in that: The silicon-based fiber powder is obtained by processing the following steps: A1. Mix and stir the chopped glass fibers and the activation solution, raise the temperature of the reaction system to 60-80°C, keep the reaction warm for 2-3 hours, and perform post-treatment to obtain activated fibers; A2. Stir and mix the activated fiber, methyl triethoxysilane, ethyl orthosilicate, 3-glycidyloxypropyl triethoxysilane and anhydrous ethanol, lower the temperature of the reaction system to 10-15°C, add hydrochloric acid solution to the reaction system, keep the reaction warm for 3-5 hours, and post-treat to obtain silicon-based fiber powder.

9. The thermal insulation brick based on cement mixture according to claim 8, characterized in that: In step A1, the amount ratio of the chopped glass fiber and the activation solution is 1g:5-6mL, and the activation solution is composed of 3-5wt% sodium hydroxide solution and 20wt% hydrogen peroxide in a volume ratio of 5:1; in step A2, the amount ratio of the activated fiber, methyl triethoxysilane, tetraethyl orthosilicate, 3-glycidyloxypropyl triethoxysilane, anhydrous ethanol and hydrochloric acid solution is 30g:10-12g:8-10g:4-6g:60mL:10mL, and the concentration of the hydrochloric acid solution is 0.8-1.2mol / L.

10. A method for preparing a thermal insulation brick based on a cement mixture according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1, adding the foaming liquid into a foaming machine for foaming to prepare foamed foam; S2, adding PEG modified aggregate, cement, silicon-based fiber powder, modified silica, and additives into a mixer and stirring for 3-5 minutes, adding drinking water into the mixer, stirring and mixing for 8-10 minutes, and then adding foaming foam into the mixer, stirring and dispersing for 1-2 minutes to obtain a foaming slurry; S3, pour the foaming slurry into several molds respectively, then scrape the slurry on the upper surface of the mold flat and seal the mold, let it stand for 4-6 hours, demold, and obtain the insulation brick blank; S4, placing the thermal insulation brick blanks in a curing room and curing them for 7 days to obtain thermal insulation bricks.

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