Lightweight thermal insulation concrete and preparation method thereof

Abstract

The invention discloses lightweight thermal insulation concrete and a preparation method thereof, and belongs to the technical field of lightweight concrete. The lightweight thermal insulation concrete is prepared from the following raw materials in parts by weight: 20 to 25 parts of fly ash geopolymer slurry, 60 to 70 parts of cement, 20 to 24 parts of glass beads, 100 to 110 parts of modified ceramsite, 15 to 17 parts of polypropylene fiber, 5 to 7 parts of potassium silicate, 16 to 20 parts of pure acrylic emulsion, 1.5 to 2 parts of gamma-aminopropyltriethoxysilane, 0.8 to 1.0 part of polycarboxylic acid water reducer and 0.3 to 0.5 part of cellulose ether. 3-5 parts of a foaming agent, 1-2 parts of a synergist and 50-60 parts of water. The lightweight concrete prepared by adding the modified ceramsite, the synergist dipropylene glycol monomethyl ether, the compound foaming agent and other specific material components is good in thermal insulation effect and excellent in crack resistance and frost resistance, and the comprehensive performance is synchronously improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of lightweight concrete, and particularly relates to a lightweight thermal insulation concrete and a preparation method thereof. Background Art

[0002] Lightweight concrete is a kind of concrete with a relatively low density and light weight. Compared with traditional concrete, it has a lower density, and the density range of commonly used lightweight concrete is between 500 kg / m 3 and 2000 kg / m 3 This makes lightweight concrete have good sound absorption performance and heat insulation performance. In addition, lightweight concrete also has a lower thermal conductivity and better seismic performance. Compared with traditional concrete structures, the construction of lightweight concrete is more convenient. Due to its relatively light materials, construction workers can carry and install it more quickly and easily. In addition, lightweight concrete can also be quickly poured through formwork shaping, reducing the construction period and labor costs.

[0003] The application of lightweight concrete in residential buildings has been widely explored and practiced. For example, in residential buildings, lightweight concrete can be used as structural elements such as partition walls, floors, and roofs. Due to its lower density and good sound insulation performance, lightweight concrete can effectively reduce noise transmission and provide a more comfortable living environment. In addition, lightweight concrete also has good heat insulation performance, which can reduce energy consumption and improve the energy-saving effect of buildings. However, the strength of lightweight concrete is usually much lower than that of ordinary concrete, which limits its application in load-bearing structures. Its porous structure makes it have poor frost resistance and is prone to shrinkage and cracking, affecting the structural integrity. Therefore, it is urgent to invent a lightweight thermal insulation concrete through reasonable design, which has excellent crack resistance and frost resistance while having good heat insulation performance, and has excellent comprehensive performance, and can achieve an elegant appearance, stable mechanical properties, and reliable durability in buildings. Summary of the Invention

[0004] The purpose of the present invention is to provide a lightweight thermal insulation concrete, which has good heat insulation effect, excellent crack resistance and frost resistance, and excellent mechanical properties.

[0005] To achieve the above technical purpose, the technical solution adopted by the present invention is as follows:

[0006] A lightweight thermal insulation concrete, comprising the following raw materials in parts by weight: 20-25 parts of fly ash geopolymer slurry, 60-70 parts of cement, 20-24 parts of vitrified microspheres, 100-110 parts of modified ceramsite, 15-17 parts of polypropylene fiber, 5-7 parts of potassium silicate, 16-20 parts of pure acrylic emulsion, 1.5-2 parts of γ-aminopropyltriethoxysilane, 0.8-1.0 part of polycarboxylate water reducer, 0.3-0.5 part of cellulose ether, 3-5 parts of foaming agent, 1-2 parts of synergist, and 50-60 parts of water.

[0007] Further, the preparation method of the fly ash geopolymer slurry is as follows: solid sodium hydroxide is added to deionized water to prepare a 10 mol / L sodium hydroxide solution. The sodium hydroxide solution and water glass are mixed in proportion and stirred until uniform to obtain an activator. The fly ash is dried and sieved through a 100-mesh sieve. The activator is slowly poured into the fly ash, and then water is added. Stir at 800 rpm for 5 - 10 minutes until the slurry becomes uniformly viscous to obtain the fly ash geopolymer slurry.

[0008] Furthermore, the volume ratio of the sodium hydroxide to the water glass is 1:2; the modulus of the water glass is 1.5; the mass ratio of the fly ash, the activator, and the water is 2:1:1.

[0009] Further, the preparation method of the modified ceramsite is as follows:

[0010] (1) Prepare a 1 mol / L calcium chloride solution and a sodium carbonate solution, and mix them in a volume ratio of 1:1 to form a mineralization solution. Immerse the ceramsite in the mineralization solution, place it in a constant temperature shaker and react for 24 h. Take out the ceramsite, wash it 3 times with deionized water and then dry it;

[0011] (2) Mix the nano-silica sol and the graphene dispersion liquid in a ratio of 10:1, stir evenly to obtain a composite sol. Spray the composite sol on the ceramsite treated in step (1). The sprayed ceramsite is dried at 100 °C for 1 hour, then calcined at 300 °C for 1 hour, and then spray a 10% water glass on the surface of the ceramsite to obtain the modified ceramsite.

[0012] Furthermore, the mineralization solution can completely immerse the ceramsite.

[0013] Furthermore, the preparation method of the graphene dispersion liquid is as follows: Take 100 mL of deionized water, add 10 mg of sodium dodecylbenzenesulfonate and stir until dissolved to obtain a dispersion medium. Slowly add 10 mg of graphene powder into the dispersion medium, perform ultrasonic treatment for 30 min to obtain a dispersion liquid. Centrifuge the dispersion liquid at 2000 rpm for 10 min, and take the supernatant to obtain a uniformly dispersed graphene dispersion liquid; the mass ratio of the composite sol to the ceramsite in step (2) is 1:9.

[0014] Further, the foaming agent includes dodecyl betaine, sorbitan oleate, and ethyl lactate, and the mass ratio of the three is 3:1:1.

[0015] Further, the synergist is dipropylene glycol methyl ether.

[0016] A preparation method of lightweight thermal insulation concrete is prepared by the following steps: Put materials such as cement, fly ash geopolymer slurry, expanded perlite, modified ceramsite, polypropylene fiber, cellulose ether, and synergist into a mixer and stir evenly; Dissolve potassium silicate in part of the water and stir until completely dissolved; Add pure acrylic emulsion, γ-aminopropyltriethoxysilane, polycarboxylate water reducer, and foaming agent to the remaining water and stir evenly to obtain a liquid mixture; Slowly pour the potassium silicate solution and the liquid mixture into the previously mixed materials while pouring and stirring to obtain lightweight concrete.

[0017] Beneficial effects

[0018] In the present invention, a calcium carbonate mineralization layer is first formed on the surface of the ceramsite to enhance the surface roughness and activity, and then a composite coating is formed by nano-silica sol and graphene to improve the strength, toughness and thermal insulation performance of the ceramsite. In the present invention, the modified ceramsite realizes the comprehensive improvement of the performance of the ceramsite through the combination of the mineralization layer and the nano-composite material coating, effectively improving the thermal insulation effect and mechanical properties of the lightweight concrete.

[0019] The present invention introduces a chemical foaming agent, which is composed of dodecyl betaine, sorbitan oleate, and ethyl lactate. Sorbitan oleate, as a surfactant, can reduce the surface tension, improve the stability and distribution of bubbles, and enhance the workability of concrete; Dodecyl betaine has good bubble and foam stabilizing properties, and can synergistically act with sorbitan oleate and ethyl lactate to improve the uniformity and stability of bubbles; Ethyl lactate can adjust the viscosity and fluidity of the system and play an auxiliary role in the formation and distribution of bubbles. The synergistic cooperation of dodecyl betaine, sorbitan oleate, and ethyl lactate stabilizes the bubble structure, reduces internal defects in concrete, forms small and uniform closed-cell structures, improves the thermal insulation performance of lightweight concrete, and at the same time the closed-cell structure reduces the penetration of moisture and harmful substances, improving the compressive strength and crack resistance of concrete.

[0020] The present invention also introduces a synergist, dipropylene glycol methyl ether. Dipropylene glycol methyl ether can improve the workability of concrete, help maintain the moisture in concrete, reduce the risk of dry shrinkage cracks caused by rapid evaporation of moisture, and can also optimize the microstructure of concrete, enhance the impermeability and frost resistance of concrete, and indirectly improve the thermal insulation performance.

[0021] The lightweight thermal insulation concrete prepared by the present invention by adding specific material components such as modified ceramsite, synergist dipropylene glycol methyl ether, and compound foaming agent has good thermal insulation effect, good crack resistance and frost resistance, and the comprehensive performance is improved synchronously. Specific embodiments

[0022] The technical solutions of the present invention will be further described below in conjunction with specific embodiments, but not limited thereto.

[0023] Example 1

[0024] A lightweight thermal insulation concrete, comprising raw materials in the following parts by weight: 20 parts of fly ash geopolymer slurry, 60 parts of cement, 20 parts of expanded perlite, 100 parts of modified ceramsite, 15 parts of polypropylene fiber, 5 parts of potassium silicate, 16 parts of pure acrylic emulsion, 1.5 parts of γ-aminopropyltriethoxysilane, 0.8 part of polycarboxylate water reducer, 0.3 part of cellulose ether, 3 parts of foaming agent, 1 part of synergist, and 50 parts of water.

[0025] The preparation method of the fly ash geopolymer slurry is as follows: solid sodium hydroxide is added to deionized water to prepare a 10 mol / L sodium hydroxide solution, the sodium hydroxide solution and water glass are mixed in proportion, and stirred until uniform to obtain an activator; the fly ash is dried and sieved through a 100-mesh sieve, the activator is slowly poured into the fly ash and then water is added, and stirred at 800 rpm for 5 - 10 minutes until the slurry becomes uniformly viscous to obtain the fly ash geopolymer slurry.

[0026] The volume ratio of the sodium hydroxide to the water glass is 1:2; the modulus of the water glass is 1.5; the mass ratio of the fly ash, activator, and water is 2:1:1.

[0027] The preparation method of the modified ceramsite is as follows:

[0028] (1) Prepare a 1 mol / L calcium chloride solution and a sodium carbonate solution, and mix the two in a volume ratio of 1:1 to form a mineralization solution; soak the ceramsite in the mineralization solution, place it in a constant temperature shaker and react for 24 h, take out the ceramsite, wash it 3 times with deionized water and then dry it;

[0029] (2) Mix the nano-silica sol and the graphene dispersion liquid in a ratio of 10:1, stir evenly to obtain a composite sol, spray the composite sol on the ceramsite treated in step (1), the sprayed ceramsite is dried at 100 °C for 1 hour, then calcined at 300 °C for 1 hour, and then spray a 10% water glass on the surface of the ceramsite to obtain the modified ceramsite.

[0030] The preparation method of the graphene dispersion liquid is as follows: take 100 mL of deionized water, add 10 mg of sodium dodecylbenzenesulfonate and stir until dissolved to obtain a dispersion medium, slowly add 10 mg of graphene powder to the dispersion medium, perform ultrasonic treatment for 30 min to obtain a dispersion liquid, centrifuge the dispersion liquid at 2000 rpm for 10 min, and take the supernatant to obtain a uniformly dispersed graphene dispersion liquid.

[0031] In step (2), the mass ratio of the composite sol to the ceramsite is 1:9.

[0032] The foaming agent includes dodecyl betaine, sorbitan oleate, and ethyl lactate, and the mass ratio of the three is 3:1:1.

[0033] The synergist is dipropylene glycol methyl ether.

[0034] A preparation method of lightweight thermal insulation concrete is prepared by the following steps: putting materials such as cement, fly ash geopolymer slurry, vitrified microspheres, modified ceramsite, polypropylene fiber, cellulose ether, and synergist into a mixer and stirring evenly; dissolving potassium silicate in part of the water and stirring until completely dissolved; adding pure acrylic emulsion, γ-aminopropyltriethoxysilane, polycarboxylate water reducer, and foaming agent to the remaining water and stirring evenly to obtain a liquid mixture; mixing the potassium silicate solution and the liquid mixture and slowly pouring them into the previously mixed materials while stirring to obtain lightweight thermal insulation concrete.

[0035] Example 2

[0036] A lightweight thermal insulation concrete includes the following raw materials in parts by weight: 23 parts of fly ash geopolymer slurry, 65 parts of cement, 22 parts of vitrified microspheres, 105 parts of modified ceramsite, 16 parts of polypropylene fiber, 6 parts of potassium silicate, 18 parts of pure acrylic emulsion, 1.5 parts of γ-aminopropyltriethoxysilane, 0.8 part of polycarboxylate water reducer, 0.4 part of cellulose ether, 4 parts of foaming agent, 1 part of synergist, and 55 parts of water.

[0037] The preparation method of the fly ash geopolymer slurry is as follows: adding solid sodium hydroxide to deionized water to prepare a 10 mol / L sodium hydroxide solution, mixing the sodium hydroxide solution and water glass in proportion and stirring until uniform to obtain an activator; drying fly ash and passing it through a 100-mesh sieve, slowly pouring the activator into the fly ash and then adding water, and stirring at 800 rpm for 5-10 minutes until the slurry becomes uniformly viscous to obtain the fly ash geopolymer slurry.

[0038] The volume ratio of the sodium hydroxide to the water glass is 1:2; the modulus of the water glass is 1.5; the mass ratio of the fly ash, activator, and water is 2:1:1.

[0039] The preparation method of the modified ceramsite is as follows:

[0040] (1) Preparing a 1 mol / L calcium chloride solution and a sodium carbonate solution, mixing the two according to a volume ratio of 1:1 to form a mineralization solution; soaking the ceramsite in the mineralization solution, placing it in a constant temperature shaker to react for 24 h, taking out the ceramsite, washing it 3 times with deionized water and then drying it;

[0041] (2) Mixing nano-silica sol and graphene dispersion liquid in a ratio of 10:1, stirring evenly to obtain a composite sol, spraying the composite sol on the ceramsite treated in step (1), drying the sprayed ceramsite at 100 °C for 1 hour, then calcining it at 300 °C for 1 hour, and then spraying a 10% water glass on the surface of the ceramsite to obtain the modified ceramsite.

[0042] The preparation method of the graphene dispersion is as follows: Take 100 mL of deionized water, add 10 mg of sodium dodecylbenzenesulfonate and stir until dissolved to obtain a dispersion medium. Slowly add 10 mg of graphene powder into the dispersion medium, and perform ultrasonic treatment for 30 min to obtain a dispersion. Centrifuge the dispersion at 2000 rpm for 10 min, and take the supernatant to obtain a uniformly dispersed graphene dispersion.

[0043] In the step (2), the mass ratio of the composite sol to the ceramsite is 1:9.

[0044] The foaming agent includes dodecyl betaine, sorbitan oleate, and ethyl lactate, and the mass ratio of the three is 3:1:1.

[0045] The synergist is dipropylene glycol methyl ether.

[0046] A preparation method of lightweight thermal insulation concrete is prepared by the following steps: Put materials such as cement, fly ash geopolymer slurry, expanded perlite, modified ceramsite, polypropylene fiber, cellulose ether, and synergist into a mixer and stir evenly; Dissolve potassium silicate in part of the water and stir until completely dissolved; Add pure acrylic emulsion, γ-aminopropyltriethoxysilane, polycarboxylate water reducer, and foaming agent to the remaining water and stir evenly to obtain a liquid mixture; Mix the potassium silicate solution and the liquid mixture and slowly pour them into the previously mixed materials while stirring to obtain lightweight thermal insulation concrete.

[0047] Example 3

[0048] A lightweight thermal insulation concrete, comprising the following raw materials in parts by weight: 25 parts of fly ash geopolymer slurry, 70 parts of cement, 24 parts of expanded perlite, 110 parts of modified ceramsite, 17 parts of polypropylene fiber, 7 parts of potassium silicate, 20 parts of pure acrylic emulsion, 2 parts of γ-aminopropyltriethoxysilane, 1.0 part of polycarboxylate water reducer, 0.5 part of cellulose ether, 5 parts of foaming agent, 2 parts of synergist, and 60 parts of water.

[0049] The preparation method of the fly ash geopolymer slurry is as follows: Add solid sodium hydroxide to deionized water to prepare a 10 mol / L sodium hydroxide solution. Mix the sodium hydroxide solution and water glass in proportion and stir until uniform to obtain an activator; Dry the fly ash and pass it through a 100-mesh sieve. Slowly pour the activator into the fly ash and then add water, and stir at 800 rpm for 5 - 10 minutes until the slurry becomes uniformly viscous to obtain the fly ash geopolymer slurry.

[0050] The volume ratio of the sodium hydroxide to the water glass is 1:2; the modulus of the water glass is 1.5; the mass ratio of the fly ash, activator, and water is 2:1:1.

[0051] The preparation method of the modified ceramsite is as follows:

[0052] (1) Prepare 1 mol / L calcium chloride solution and sodium carbonate solution, mix them in a volume ratio of 1:1 to form a mineralization solution; soak the ceramsite in the mineralization solution, place it in a constant temperature shaker and react for 24 h, take out the ceramsite, wash it 3 times with deionized water and then dry it;

[0053] (2) Mix the nano-silica sol and the graphene dispersion liquid in a ratio of 10:1, stir evenly to obtain a composite sol, spray the composite sol on the ceramsite treated in step (1), dry the sprayed ceramsite at 100 °C for 1 hour, then calcine it at 300 °C for 1 hour, and then spray 10% water glass on the surface of the ceramsite to obtain the modified ceramsite.

[0054] The preparation method of the graphene dispersion liquid is as follows: Take 100 mL of deionized water, add 10 mg of sodium dodecylbenzenesulfonate and stir until dissolved to obtain a dispersion medium, slowly add 10 mg of graphene powder to the dispersion medium, ultrasonically treat it for 30 min to obtain a dispersion liquid, centrifuge the dispersion liquid at 2000 rpm for 10 min, and take the supernatant to obtain a uniformly dispersed graphene dispersion liquid.

[0055] In the step (2), the mass ratio of the composite sol to the ceramsite is 1:9.

[0056] The foaming agent includes dodecyl betaine, sorbitan oleate, and ethyl lactate, and the mass ratio of the three is 3:1:1.

[0057] The synergist is dipropylene glycol methyl ether.

[0058] A preparation method of lightweight thermal insulation concrete is prepared by the following steps: Put materials such as cement, fly ash geopolmer slurry, expanded perlite, modified ceramsite, polypropylene fiber, cellulose ether, and synergist into a mixer and stir evenly; Dissolve potassium silicate in part of the water and stir until completely dissolved; Add pure acrylic emulsion, γ-aminopropyltriethoxysilane, polycarboxylate water reducer, and foaming agent to the remaining water and stir evenly to obtain a liquid mixture; Mix the potassium silicate solution and the liquid mixture and slowly pour them into the previously mixed materials while stirring to obtain lightweight thermal insulation concrete.

[0059] Comparative Example 1

[0060] A lightweight thermal insulation concrete, comprising the following raw materials in parts by weight: 25 parts of fly ash geopolmer slurry, 70 parts of cement, 24 parts of expanded perlite, 110 parts of ceramsite, 17 parts of polypropylene fiber, 7 parts of potassium silicate, 20 parts of pure acrylic emulsion, 2 parts of γ-aminopropyltriethoxysilane, 1.0 part of polycarboxylate water reducer, 0.5 part of cellulose ether, 5 parts of foaming agent, 2 parts of synergist, and 60 parts of water.

[0061] The preparation method of the fly ash geopolymer slurry is as follows: Solid sodium hydroxide is added to deionized water to prepare a 10 mol / L sodium hydroxide solution. The sodium hydroxide solution and water glass are mixed in proportion and stirred until uniform to obtain an activator. The fly ash is dried and screened through a 100-mesh sieve. The activator is slowly poured into the fly ash, and then water is added. Stir at 800 rpm for 5 - 10 minutes until the slurry becomes uniformly viscous to obtain the fly ash geopolymer slurry.

[0062] The volume ratio of the sodium hydroxide to the water glass is 1:2; the modulus of the water glass is 1.5; the mass ratio of the fly ash, activator, and water is 2:1:1.

[0063] The foaming agent includes dodecyl betaine, sorbitan oleate, and ethyl lactate, and the mass ratio of the three is 3:1:1.

[0064] The synergist is dipropylene glycol methyl ether.

[0065] A preparation method of lightweight thermal insulation concrete is prepared by the following steps: Put materials such as cement, fly ash geopolymer slurry, expanded perlite, ceramsite, polypropylene fiber, cellulose ether, and synergist into a mixer and stir evenly; Dissolve potassium silicate in part of the water and stir until completely dissolved; Add pure acrylic emulsion, γ-aminopropyltriethoxysilane, polycarboxylate water reducer, and foaming agent to the remaining water and stir evenly to obtain a liquid mixture; Mix the potassium silicate solution and the liquid mixture and slowly pour them into the previously mixed materials while stirring to obtain the lightweight thermal insulation concrete.

[0066] Compared with Example 3, in this comparative example, except that the ceramsite is not modified, the other raw materials and steps are the same as those in Example 3.

[0067] Comparative Example 2

[0068] A lightweight thermal insulation concrete includes the following raw materials in parts by weight: 25 parts of fly ash geopolymer slurry, 70 parts of cement, 24 parts of expanded perlite, 110 parts of modified ceramsite, 17 parts of polypropylene fiber, 7 parts of potassium silicate, 20 parts of pure acrylic emulsion, 2 parts of γ-aminopropyltriethoxysilane, 1.0 part of polycarboxylate water reducer, 0.5 part of cellulose ether, 5 parts of foaming agent, 2 parts of synergist, and 60 parts of water.

[0069] The preparation method of the fly ash geopolymer slurry is as follows: Solid sodium hydroxide is added to deionized water to prepare a 10 mol / L sodium hydroxide solution. The sodium hydroxide solution and water glass are mixed in proportion and stirred until uniform to obtain an activator. The fly ash is dried and screened through a 100-mesh sieve. The activator is slowly poured into the fly ash, and then water is added. Stir at 800 rpm for 5 - 10 minutes until the slurry becomes uniformly viscous to obtain the fly ash geopolymer slurry.

[0070] The volume ratio of the sodium hydroxide to the water glass is 1:2; the modulus of the water glass is 1.5; the mass ratio of the fly ash, the activator, and the water is 2:1:1.

[0071] The preparation method of the modified ceramsite is as follows:

[0072] (1) Prepare a 1 mol / L calcium chloride solution and a sodium carbonate solution, mix the two according to a volume ratio of 1:1 to form a mineralization solution; immerse the ceramsite in the mineralization solution, place it in a constant temperature shaker and react for 24 h, take out the ceramsite, wash it 3 times with deionized water and then dry it;

[0073] (2) Mix the nano-silica sol and the graphene dispersion liquid according to a ratio of 10:1, stir evenly to obtain a composite sol, spray the composite sol on the ceramsite treated in step (1), dry the sprayed ceramsite at 100 °C for 1 hour, then calcine it at 300 °C for 1 hour, and then spray a 10% water glass onto the surface of the ceramsite to obtain the modified ceramsite.

[0074] The preparation method of the graphene dispersion liquid is as follows: Take 100 mL of deionized water, add 10 mg of sodium dodecylbenzenesulfonate and stir until dissolved to obtain a dispersion medium, slowly add 10 mg of graphene powder to the dispersion medium, perform ultrasonic treatment for 30 min to obtain a dispersion liquid, centrifuge the dispersion liquid at 2000 rpm for 10 min, and take the supernatant to obtain a uniformly dispersed graphene dispersion liquid.

[0075] In step (2), the mass ratio of the composite sol to the ceramsite is 1:9.

[0076] The foaming agent includes dodecyl betaine and sorbitan oleate, and the mass ratio of the two is 3:1.

[0077] The synergist is dipropylene glycol methyl ether.

[0078] A preparation method of a lightweight thermal insulation concrete is prepared by the following steps: Put materials such as cement, fly ash geopolymer slurry, expanded perlite, modified ceramsite, polypropylene fiber, cellulose ether, and synergist into a mixer and stir evenly; Dissolve potassium silicate in part of the water and stir until completely dissolved; Add pure acrylic emulsion, γ-aminopropyltriethoxysilane, polycarboxylate water reducer, and foaming agent to the remaining water and stir evenly to obtain a liquid mixture; Mix the potassium silicate solution and the liquid mixture and slowly pour them into the previously mixed materials while stirring to obtain the lightweight thermal insulation concrete.

[0079] Compared with Example 3, in this comparative example, except that ethyl lactate is not added to the foaming agent, the other raw materials and steps are the same as those in Example 3.

[0080] Comparative Example 3

[0081] A lightweight thermal insulation concrete, comprising raw materials in the following parts by weight: 25 parts of fly ash geopolymer slurry, 70 parts of cement, 24 parts of expanded perlite, 110 parts of modified ceramsite, 17 parts of polypropylene fiber, 7 parts of potassium silicate, 20 parts of pure acrylic emulsion, 2 parts of γ-aminopropyltriethoxysilane, 1.0 part of polycarboxylate water reducer, 0.5 part of cellulose ether, 5 parts of foaming agent, 2 parts of synergist, and 60 parts of water.

[0082] The preparation method of the fly ash geopolymer slurry is as follows: solid sodium hydroxide is added to deionized water to prepare a 10 mol / L sodium hydroxide solution, the sodium hydroxide solution and water glass are mixed in proportion, and stirred until uniform to obtain an activator; the fly ash is dried and sieved through a 100-mesh sieve, the activator is slowly poured into the fly ash and then water is added, and stirred at 800 rpm for 5 - 10 minutes until the slurry becomes uniformly viscous to obtain the fly ash geopolymer slurry.

[0083] The volume ratio of the sodium hydroxide to the water glass is 1:2; the modulus of the water glass is 1.5; the mass ratio of the fly ash, activator, and water is 2:1:1.

[0084] The preparation method of the modified ceramsite is as follows:

[0085] (1) Prepare a 1 mol / L calcium chloride solution and a sodium carbonate solution, and mix them in a volume ratio of 1:1 to form a mineralization solution; soak the ceramsite in the mineralization solution, place it in a constant temperature shaker for reaction for 24 h, take out the ceramsite, wash it 3 times with deionized water, and then dry it;

[0086] (2) Mix the nano-silica sol and the graphene dispersion liquid in a ratio of 10:1, stir evenly to obtain a composite sol, spray the composite sol on the ceramsite treated in step (1), the sprayed ceramsite is dried at 100 °C for 1 hour, then calcined at 300 °C for 1 hour, and then spray a 10% water glass on the surface of the ceramsite to obtain the modified ceramsite.

[0087] The preparation method of the graphene dispersion liquid is as follows: take 100 mL of deionized water, add 10 mg of sodium dodecylbenzenesulfonate and stir until dissolved to obtain a dispersion medium, slowly add 10 mg of graphene powder into the dispersion medium, ultrasonically treat for 30 min to obtain a dispersion liquid, centrifuge the dispersion liquid at 2000 rpm for 10 min, and take the supernatant to obtain a uniformly dispersed graphene dispersion liquid.

[0088] In step (2), the mass ratio of the composite sol to the ceramsite is 1:9.

[0089] The foaming agent includes dodecyl betaine and ethyl lactate, and the mass ratio of the two is 3:1.

[0090] The synergist is dipropylene glycol methyl ether.

[0091] A preparation method of lightweight thermal insulation concrete is prepared by the following steps: Put materials such as cement, fly ash geopolymer slurry, expanded perlite, modified ceramsite, polypropylene fiber, cellulose ether, and synergist into a mixer and stir evenly; Dissolve potassium silicate in part of the water and stir until completely dissolved; Add pure acrylic emulsion, γ-aminopropyltriethoxysilane, polycarboxylate water reducer, and foaming agent to the remaining water and stir evenly to obtain a liquid mixture; Slowly pour the potassium silicate solution and the liquid mixture into the previously mixed materials while stirring to obtain lightweight thermal insulation concrete.

[0092] Compared with Example 3, in this comparative example, except that sorbitan oleate is not added to the foaming agent, the other raw materials and steps are the same as those in Example 3.

[0093] Comparative Example 4

[0094] A lightweight thermal insulation concrete includes the following raw materials in parts by weight: 25 parts of fly ash geopolymer slurry, 70 parts of cement, 24 parts of expanded perlite, 110 parts of modified ceramsite, 17 parts of polypropylene fiber, 7 parts of potassium silicate, 20 parts of pure acrylic emulsion, 2 parts of γ-aminopropyltriethoxysilane, 1.0 part of polycarboxylate water reducer, 0.5 part of cellulose ether, 5 parts of foaming agent, and 60 parts of water.

[0095] The preparation method of the fly ash geopolymer slurry is as follows: Solid sodium hydroxide is added to deionized water to prepare a 10 mol / L sodium hydroxide solution. The sodium hydroxide solution and water glass are mixed in proportion and stirred until uniform to obtain an activator; The fly ash is dried and sieved through a 100-mesh sieve. The activator is slowly poured into the fly ash and then water is added, and it is stirred at 800 rpm for 5 - 10 minutes until the slurry becomes uniformly viscous to obtain the fly ash geopolymer slurry.

[0096] The volume ratio of the sodium hydroxide to the water glass is 1:2; The modulus of the water glass is 1.5; The mass ratio of the fly ash, activator, and water is 2:1:1.

[0097] The preparation method of the modified ceramsite is as follows:

[0098] (1) Prepare a 1 mol / L calcium chloride solution and a sodium carbonate solution, and mix them in a volume ratio of 1:1 to form a mineralization solution; Immerse the ceramsite in the mineralization solution, place it in a constant temperature shaker and react for 24 h, take out the ceramsite, wash it 3 times with deionized water and then dry it;

[0099] (2) Mix the nano-silica sol and the graphene dispersion liquid in a ratio of 10:1, stir evenly to obtain a composite sol, spray the composite sol on the ceramsite treated in step (1), dry the sprayed ceramsite at 100 °C for 1 hour, then calcine it at 300 °C for 1 hour, and then spray a 10% water glass on the surface of the ceramsite to obtain the modified ceramsite.

[0100] The preparation method of the graphene dispersion is as follows: Take 100 mL of deionized water, add 10 mg of sodium dodecylbenzenesulfonate and stir until dissolved to obtain a dispersion medium. Slowly add 10 mg of graphene powder into the dispersion medium, perform ultrasonic treatment for 30 min to obtain a dispersion liquid, centrifuge the dispersion liquid at 2000 rpm for 10 min, and take the supernatant to obtain a uniformly dispersed graphene dispersion liquid.

[0101] In the step (2), the mass ratio of the composite sol to the ceramsite is 1:9.

[0102] The foaming agent includes dodecyl betaine, sorbitan oleate, and ethyl lactate, and the mass ratio of the three is 3:1:1.

[0103] A preparation method of lightweight thermal insulation concrete is prepared by the following steps: Put materials such as cement, fly ash geopolymer slurry, expanded perlite, modified ceramsite, polypropylene fiber, and cellulose ether into a mixer and stir evenly; Dissolve potassium silicate in part of the water and stir until completely dissolved; Add pure acrylic emulsion, γ-aminopropyltriethoxysilane, polycarboxylate water reducer, and foaming agent into the remaining water and stir evenly to obtain a liquid mixture; Mix the potassium silicate solution and the liquid mixture and slowly pour them into the previously mixed materials while stirring to obtain lightweight thermal insulation concrete.

[0104] Compared with Example 3, in this comparative example, except for not adding a synergist, the other raw materials and steps are the same as those in Example 3.

[0105] Comparative Example 5

[0106] A lightweight thermal insulation concrete includes the following raw materials in parts by weight: 25 parts of fly ash geopolymer slurry, 70 parts of cement, 24 parts of expanded perlite, 99 parts of ceramsite, 10 parts of nano-silica, 1 part of graphene dispersion liquid, 17 parts of polypropylene fiber, 7 parts of potassium silicate, 20 parts of pure acrylic emulsion, 2 parts of γ-aminopropyltriethoxysilane, 1.0 part of polycarboxylate water reducer, 0.5 part of cellulose ether, 5 parts of foaming agent, 2 parts of synergist, and 60 parts of water.

[0107] The preparation method of the fly ash geopolymer slurry is as follows: Add solid sodium hydroxide to deionized water to prepare a 10 mol / L sodium hydroxide solution. Mix the sodium hydroxide solution and water glass in proportion and stir until uniform to obtain an activator; Dry the fly ash and pass it through a 100-mesh sieve. Slowly pour the activator into the fly ash and then add water, and stir at 800 rpm for 5 - 10 minutes until the slurry becomes uniformly viscous to obtain the fly ash geopolymer slurry.

[0108] The volume ratio of the sodium hydroxide to the water glass is 1:2; The modulus of the water glass is 1.5; The mass ratio of the fly ash, activator, and water is 2:1:1.

[0109] The foaming agent includes dodecyl betaine, sorbitan oleate, and ethyl lactate, and the mass ratio of the three is 3:1:1.

[0110] The synergist is dipropylene glycol methyl ether.

[0111] A preparation method of lightweight thermal insulation concrete is prepared by the following steps: putting materials such as cement, fly ash geopolmer slurry, expanded perlite, ceramsite, nano-silica, graphene dispersion, polypropylene fiber, cellulose ether, and synergist into a mixer and stirring evenly; dissolving potassium silicate in part of the water and stirring until completely dissolved; adding pure acrylic emulsion, γ-aminopropyltriethoxysilane, polycarboxylate water reducer, and foaming agent to the remaining water and stirring evenly to obtain a liquid mixture; mixing the potassium silicate solution and the liquid mixture and slowly pouring them into the previously mixed materials while stirring to obtain lightweight thermal insulation concrete.

[0112] Compared with Example 3, in this comparative example, except that the ceramsite is not modified and graphene dispersion and nano-silica are added alone, the other raw materials and steps are the same as those in Example 3.

[0113] Performance test

[0114] The compressive strength of the concrete test block is determined with reference to GB / T50081-2016 "Standard Test Method for Mechanical Properties of Ordinary Concrete";

[0115] The thermal conductivity of the concrete test block is determined with reference to GB / T10294-2008 "Determination of Steady-State Thermal Resistance and Related Properties of Thermal Insulation Materials - Guarded Hot Plate Method";

[0116] The frost resistance test of the concrete test block is carried out with reference to GB / T50082-2009 "Standard Test Method for Long-Term Performance and Durability of Ordinary Concrete";

[0117] The early anti-cracking performance test of the concrete test block is carried out with reference to GB / T50081-2016 "Standard Test Method for Mechanical Properties of Ordinary Concrete". Standard test blocks are made for each treatment, and after 72 hours of concrete pouring, the total cracking area of the cracks is measured.

[0118] Table 1 Performance test results

[0119]

[0120]

[0121] It can be seen from the data in Table 1 that the lightweight concrete of Examples 1-3 of the present invention can achieve a minimum thermal conductivity of 0.32 W / (m·k) and a minimum total cracking area of 40.2 mm 2 / m 2, indicating that the lightweight concrete of the present invention has good heat insulation effect and anti-cracking performance. In addition, it can be seen from the data in Table 1 that the lightweight concrete of the present invention also has good compressive strength and frost resistance.

[0122] Combining the data of Example 3 and Comparative Example 1 in Table 1, it can be seen that the modification of ceramsite has a significant impact on the strength of concrete and improves the heat insulation performance at the same time. This is mainly because after calcination, a dense protective layer is formed on the ceramsite through mineralization and the composite coating of nano-silica and graphene, increasing the strength of the ceramsite. When used as aggregate in concrete, it improves the overall compressive strength of the concrete. In addition, optimizing the ceramsite coating with nano-silica and graphene also improves the heat insulation performance of the lightweight concrete.

[0123] Combining the data of Example 3 and Comparative Examples 2 and 3 in Table 1, it can be seen that the heat insulation performance of the lightweight concrete in Comparative Examples 2 and 3 with changed foaming agent composition has decreased significantly. This is because sorbitan oleate, as a surfactant, can reduce the surface tension, improve the stability and distribution of bubbles, and enhance the workability of concrete; dodecyl betaine has good foaming and foam-stabilizing properties and can cooperate with sorbitan oleate and ethyl lactate to improve the uniformity and stability of bubbles; ethyl lactate can adjust the viscosity and fluidity of the system and play an auxiliary role in the formation and distribution of bubbles. The synergistic cooperation of dodecyl betaine, sorbitan oleate, and ethyl lactate stabilizes the bubble structure, reduces internal defects in concrete, forms fine and uniform closed-cell structures, improves the heat insulation and heat preservation performance of lightweight concrete, and at the same time, the closed-cell structure reduces the penetration of moisture and harmful substances, improving the compressive strength and crack resistance of concrete. Therefore, in the concrete of Comparative Examples 2 and 3 with changed foaming agent composition, the synergistic cooperation of dodecyl betaine, sorbitan oleate, and ethyl lactate disappears, resulting in a decline in the heat insulation performance and other properties of the concrete.

[0124] Combining the data of Example 3 and Comparative Example 4 in Table 1, it can be seen that the addition of the synergist dipropylene glycol methyl ether can significantly improve the crack resistance and frost resistance of lightweight concrete. This is because dipropylene glycol methyl ether can improve the workability of concrete, help maintain the moisture in the concrete, reduce the risk of dry shrinkage cracks caused by rapid evaporation of moisture, and can also optimize the microstructure of concrete, enhance the impermeability and frost resistance of concrete, and indirectly improve the heat insulation performance.

[0125] Combining the data of Example 3 and Comparative Example 5 in Table 1, it can be seen that when nano-silica and graphene dispersion liquid are added to the concrete alone, the properties of the lightweight concrete also decline compared with those of Example 3 of the present invention, indicating that after the ceramsite is modified by specific steps in the present invention, the nano-silica and graphene dispersion liquid can better play its role in improving the properties of the lightweight concrete.

[0126] From the data of Example 3 and Comparative Examples 1-5 in Table 1, it can be seen that the lightweight concrete prepared from the specific raw material components used in the lightweight thermal insulation concrete of the present application has good thermal insulation effect, good crack resistance and frost resistance, and good mechanical properties.

[0127] It should be noted that the above-mentioned embodiments are only some embodiments of the preferred ways to implement the present invention, rather than all embodiments. Obviously, based on the above embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

Claims

1. A lightweight thermal insulation concrete, characterized in that, It comprises the following raw materials in parts by weight: 20 - 25 parts of fly ash geopolymer slurry, 60 - 70 parts of cement, 20 - 24 parts of vitrified microspheres, 100 - 110 parts of modified ceramsite, 15 - 17 parts of polypropylene fiber, 5 - 7 parts of potassium silicate, 16 - 20 parts of pure acrylic emulsion, 1.5 - 2 parts of γ-aminopropyltriethoxysilane, 0.8 - 1.0 part of polycarboxylate water reducer, 0.3 - 0.5 part of cellulose ether, 3 - 5 parts of foaming agent, 1 - 2 parts of synergist, and 50 - 60 parts of water.

2. The lightweight thermal insulation concrete according to claim 1, wherein The preparation method of the fly ash geopolymer slurry is as follows: Solid sodium hydroxide is added to deionized water to prepare a 10 mol / L sodium hydroxide solution. The sodium hydroxide solution and water glass are mixed in proportion and stirred until uniform to obtain an activator. The fly ash is dried and sieved through a 100-mesh sieve. The activator is slowly poured into the fly ash, and then water is added. Stir at 800 rpm for 5 - 10 minutes until the slurry becomes uniformly viscous to obtain the fly ash geopolymer slurry.

3. The lightweight thermal insulation concrete according to claim 2, wherein, The volume ratio of the sodium hydroxide to the water glass is 1:2; the modulus of the water glass is 1.5; the mass ratio of the fly ash, activator, and water is 2:1:

1.

4. The lightweight thermal insulation concrete according to claim 1, wherein, The preparation method of the modified ceramsite is as follows: (1) Prepare a 1 mol / L calcium chloride solution and a sodium carbonate solution, and mix the two in a volume ratio of 1:1 to form a mineralization solution. The ceramsite is soaked in the mineralization solution, placed in a constant temperature shaker for reaction for 24 h, and the ceramsite is taken out and washed 3 times with deionized water and then dried. (2) Mix the nano-silica sol and the graphene dispersion liquid in a ratio of 10:1, stir evenly to obtain a composite sol. Spray the composite sol on the ceramsite treated in step (1). The sprayed ceramsite is dried at 100 °C for 1 hour, then calcined at 300 °C for 1 hour, and then a 10% water glass is sprayed onto the surface of the ceramsite to obtain the modified ceramsite.

5. The lightweight thermal insulation concrete according to claim 4, characterized in that, The preparation method of the graphene dispersion liquid is as follows: Take 100 mL of deionized water, add 10 mg of sodium dodecylbenzenesulfonate and stir until dissolved to obtain a dispersion medium. Slowly add 10 mg of graphene powder into the dispersion medium, ultrasonically treat for 30 min to obtain a dispersion liquid, centrifuge the dispersion liquid at 2000 rpm for 10 min, and take the supernatant to obtain a uniformly dispersed graphene dispersion liquid; the mass ratio of the composite sol to the ceramsite in step (2) is 1:

9.

6. The lightweight thermal insulation concrete according to claim 1, characterized in that, The foaming agent includes dodecyl betaine, sorbitan oleate, and ethyl lactate, and the mass ratio of the three is 3:1:

1.

7. The lightweight thermal insulation concrete according to claim 1, characterized in that, The synergist is dipropylene glycol methyl ether.

8. A method for preparing the lightweight thermal insulation concrete according to any one of claims 1-7, characterized in that, It is prepared by the following steps: Put materials such as cement, fly ash geopolymer slurry, vitrified microspheres, modified ceramsite, polypropylene fiber, cellulose ether, and synergist into a mixer and stir evenly; Dissolve potassium silicate in part of the water and stir until completely dissolved; Add the pure acrylic emulsion, γ-aminopropyltriethoxysilane, polycarboxylate water reducer, and foaming agent to the remaining water and stir evenly to obtain a liquid mixture; Mix the potassium silicate solution and the liquid mixture and slowly pour them into the previously mixed materials while stirring to obtain lightweight thermal insulation concrete.

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