Preparation of a foamed concrete foaming agent and application thereof in fiber-reinforced foamed concrete vacuum insulation board

Abstract

The application provides a preparation of a foamed concrete foaming agent and application in a fiber-reinforced foamed concrete vacuum insulation board. The core material of the insulation board is composed of a foamed concrete matrix and glass fiber reinforced material uniformly distributed therein, and is externally wrapped with a heat-shrinkable film and an airproof wrapping bag. The insulation board has excellent thermal insulation performance, mechanical properties and flame retardant properties. The preparation process comprises the following steps: firstly, a foaming agent is prepared by compounding surfactants (including cocamide propyl betaine and sodium dodecyl sulfate) and foam stabilizers (nano calcium aluminate particles and polyvinyl alcohol). Water, cement, fly ash, the foaming agent and glass fiber are mixed to prepare a foamed concrete slurry; the glass fiber reinforced material is added and uniformly stirred; the mixture is poured into a mold for molding; the foamed concrete insulation board prepared by using the foaming agent has significantly improved tensile strength, compressive strength and bending toughness. The insulation board of the application not only has the characteristics of light weight and high strength, but also significantly improves the flame retardant performance, and can be widely applied in the fields of building exterior wall insulation, roof heat insulation and the like.

Description

Technical Field

[0001] This invention belongs to the field of building insulation materials, specifically the preparation of a foaming agent for foamed concrete and its application in fiber-reinforced foamed concrete vacuum insulation boards. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] In the construction industry, the performance of insulation materials has a profound impact on building energy efficiency and living quality. As building energy efficiency standards continue to rise, the market is placing higher demands on insulation materials. Traditional insulation materials, such as polystyrene foam boards, while possessing some insulation capabilities, have poor fire resistance, are easily ignited by open flames, and release toxic gases, posing serious safety hazards. Furthermore, they are not easily degradable, causing long-term environmental pollution. Polyurethane foam insulation boards also have flammability issues, and the chemicals used in their production are harmful to the environment.

[0004] Foamed concrete, as an emerging thermal insulation material, has attracted much attention due to its lightweight, thermal insulation, sound insulation, and fire resistance properties. However, ordinary foamed concrete has relatively weak mechanical properties, with low tensile strength, compressive strength, and flexural toughness, limiting its application in scenarios requiring high strength. Furthermore, the insufficient stability of foam prepared with ordinary foaming agents leads to an uneven pore structure, affecting its overall performance. Adding fiber reinforcement materials is a common method to enhance the performance of foamed concrete, with glass fiber often chosen due to its high strength, high modulus, and good chemical stability. However, optimizing the foaming agent formulation to improve the overall performance of foamed concrete remains a challenge for the industry.

[0005] Regarding the structure of insulation boards, existing insulation board wrapping materials and sealing processes have defects. Some wrapping materials have poor air tightness, causing gas leakage inside the insulation board and reducing insulation performance. In addition, traditional wrapping and sealing processes are complex and not conducive to large-scale production and application. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a method for preparing a foaming agent for foamed concrete and its application in fiber-reinforced foamed concrete vacuum insulation boards.

[0007] This invention utilizes a surfactant formulated with cocamidopropyl betaine and sodium dodecyl sulfate to more effectively reduce the surface tension at the gas-liquid interface, thus making the foam liquid film more stable. The amphoteric structure of cocamidopropyl betaine allows it to maintain good surface activity under different pH conditions. Combined with sodium dodecyl sulfate, it broadens the applicable pH range of the surfactant, enhancing foam stability and durability under various conditions. Erythrite nanoparticles, as an inorganic foam stabilizer, have a large specific surface area and surface energy, allowing them to adsorb onto the surface of the foam liquid film, increasing the film's strength and elasticity and preventing foam breakage. Polyvinyl alcohol, an organic polymeric foam stabilizer, increases the viscosity of the liquid film, reduces its drainage rate, and further stabilizes the foam. The combination of these two components creates a synergistic organic-inorganic effect, significantly extending the foam's lifespan and improving the stability of foamed concrete during preparation and molding. The foaming agent prepared in this invention significantly improves the tensile strength, compressive strength, and flexural toughness of foamed concrete insulation boards. Simultaneously, this insulation board possesses excellent lightweight, high strength, and flame-retardant properties. Furthermore, this invention solves the problems of air tightness and sealing by using an innovative insulation board structure design that combines a heat-shrinkable film with vents and circular protrusions with an airtight wrapping bag, making it a promising candidate for applications in building exterior wall insulation, roof insulation, and other fields.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a foamed concrete foaming agent, comprising the following raw materials in weight percentages: 1-1.5 wt% surfactant, 2-2.5 wt% foam stabilizer, 0.5-1 wt% silane coupling agent, and the remainder being water;

[0010] The foam stabilizer includes: nano-calcite particles and polyvinyl alcohol.

[0011] In some embodiments, the surfactant includes cocamidopropyl betaine and sodium dodecyl sulfate.

[0012] A second aspect of the present invention provides a method for preparing a foamed concrete foaming agent, comprising:

[0013] Heat the surfactant solution to a predetermined temperature, add the foam stabilizer, mix well, then add the silane coupling agent and mix well to obtain the final product.

[0014] In some embodiments, the foam stabilizer is a mixture of nano-calcite particles and a polyvinyl alcohol solution.

[0015] In some embodiments, the preparation method of the nano-calcite particles includes: preparing them in an alkaline environment using aluminum sulfate octadechydrate, calcium oxide, and the surfactant sodium hexametaphosphate, wherein the molar ratio of aluminum sulfate octadechydrate to calcium oxide is 1:6-8, the mass fraction of sodium hexametaphosphate is 1-1.5 wt%, and the pH is maintained at 10-12 during the preparation process.

[0016] Preferably, the molar ratio of aluminum sulfate octahydrate to calcium oxide is 1:6, and the mass fraction of sodium hexametaphosphate is 1 wt%.

[0017] In some implementations, the silane coupling agent is specified as KH570.

[0018] A third aspect of the present invention provides the application of the above-mentioned foamed concrete foaming agent in the preparation of fiber-reinforced foamed concrete vacuum insulation boards.

[0019] A fourth aspect of the present invention provides a fiber-reinforced foamed concrete vacuum insulation board, comprising: a glass fiber reinforced foamed concrete core material, a heat-shrinkable film, and an airtight wrapping bag. The heat-shrinkable film has a plurality of air vents and is wrapped around the foamed concrete core material to form a pre-assembled core. The pre-assembled core material is vacuum-sealed by the airtight wrapping bag. Both ends of the airtight wrapping bag have pre-reserved edges, which are folded over and pasted onto the surface of the board formed by the airtight wrapping bag.

[0020] In some embodiments, the glass fiber reinforced foamed concrete core material is composed of the following raw materials in parts by weight: 0.45-0.5 parts water, 1-1.2 parts cement, 0.25-0.3 parts fly ash, 0.01-0.012 parts foaming agent, and 0.006-0.008 parts glass fiber.

[0021] Preferably, water, cement, fly ash, foaming agent and glass fiber are mixed in a ratio of 0.45:1:0.25:0.01:0.006.

[0022] In some embodiments, the cement is ordinary silicate cement.

[0023] In some embodiments, the heat-shrink film has multiple circular protrusions on its surface and multiple vent holes, which wrap around the core material.

[0024] A fifth aspect of the present invention provides a method for preparing the above-mentioned fiber-reinforced foamed concrete vacuum insulation board, comprising:

[0025] Take a portion of cement, a portion of fly ash, and all of the water, mix them evenly, and you will get a slurry;

[0026] Mix the remaining materials thoroughly to obtain the mixture;

[0027] Take a portion of the mixture and add it to the slurry, mix well, then add the remaining mixture and mix well to obtain fiber cement slurry;

[0028] The foaming agent is foamed, and the resulting foam is added to the fiber cement slurry and mixed evenly to obtain glass fiber foam concrete slurry.

[0029] The glass fiber foamed concrete slurry is poured into a mold, cured, and demolded to obtain glass fiber reinforced foamed concrete core material.

[0030] A pre-assembled core panel is formed by wrapping glass fiber reinforced foamed concrete core material with heat shrink film.

[0031] The pre-assembled core is wrapped in an airtight bag, with process-reserved edges formed at both ends of the airtight bag. These process-reserved edges are then folded over and pasted onto the surface of the core formed by the airtight bag.

[0032] More specifically, including:

[0033] Step 1: First, prepare nano-calcite particles using aluminum sulfate octadechydrate, calcium oxide, and the surfactant sodium hexametaphosphate in an alkaline environment. Dissolve polyvinyl alcohol particles in deionized water by heating in a 95°C water bath. Dissolve 1 wt% of the surfactant (including cocamidopropyl betaine and sodium dodecyl sulfate) in deionized water and heat in a 50°C water bath. Then add 2 wt% of a foam stabilizer (including nano-calcite particles and polyvinyl alcohol) and 0.5 wt% of a silane coupling agent, and stir at 50°C for 2 hours.

[0034] Step 2: Weigh all materials according to the mixing ratio. First, add half cement and half fly ash, then add all the water and stir slightly. Mix the remaining materials, then pour half of the mixture into a mixer and stir for 2 minutes. After stirring, turn over the bottom material and add the remaining material, continuing to stir for 4 minutes. At the same time, use a foaming machine to foam the foaming agent. Add the resulting foam to the fiber cement slurry and mix evenly to obtain glass fiber foam concrete slurry.

[0035] Step 3: Apply release oil to the mold surface, pour the glass fiber foamed concrete slurry into the mold, smooth the surface, and allow it to cure under standard curing conditions for 1-2 days initially. After demolding, allow it to cure for another 5-7 days for intermediate curing to obtain the glass fiber reinforced foamed concrete core material. Experiments were conducted on the prepared foamed concrete material. A portion of the material was taken out and placed into a specimen mold to prepare two sets of 40mm×40mm×160mm samples.

[0036] Step 4: Wrap the glass fiber reinforced foamed concrete core material with heat shrink film to form a pre-assembled core panel.

[0037] Step 5: Wrap the core material with an airtight wrapping bag. The two ends of the airtight wrapping bag form pre-reserved edges. Fold the pre-reserved edges over and attach them to the board surface formed by the airtight wrapping bag.

[0038] Beneficial effects of the present invention

[0039] (1) The foamed concrete insulation board prepared by the foaming agent of the present invention has significantly improved tensile strength, compressive strength and flexural toughness. The insulation board of the present invention not only has the characteristics of being lightweight and high strength, but also significantly improves flame retardant performance. It can be widely used in building exterior wall insulation, roof insulation and other fields.

[0040] (2) The preparation method of the present invention is simple, practical and easy to promote. Attached Figure Description

[0041] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. Exemplary embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0042] Figure 1 This is a schematic diagram of the glass fiber reinforced foamed concrete vacuum insulation board.

[0043] Figure 2 1-1 is a cross-sectional view of the glass fiber reinforced foamed concrete vacuum insulation board. Detailed Implementation

[0044] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0045] The present invention will be further described in detail below with reference to specific embodiments. It should be noted that the specific embodiments are explanations of the present invention and not limitations thereof.

[0046] Compressive strength test: According to GB / T 5486-2008 "Test Methods for Inorganic Rigid Thermal Insulation Products", the maximum load-bearing capacity is determined by applying a compressive load until the specimen fails. The specimen is placed in the center of the pressure plate of the testing machine, and pressure is applied at a constant loading rate (1 mm / min) until the specimen fails. The maximum load is recorded, and the compressive strength (unit: MPa) is calculated.

[0047] Tensile strength test: According to GB / T 5486-2008 "Test Methods for Inorganic Rigid Thermal Insulation Products", the specimen is placed symmetrically on the support rollers with a span of 100 mm, ensuring good contact between the specimen and the support rollers and loading rollers, and avoiding eccentric loading. A constant loading rate of 50 N / s is applied until the specimen breaks, and the maximum load is recorded.

[0048] Flexural strength test: According to GB / T 17671-1999 "Test Method for Strength of Cement Mortar (ISO Method)", the maximum load-bearing capacity of the specimen under bending load is determined by a three-point or four-point bending test. The specimen is placed on the support rollers of the testing machine, ensuring the span meets the standard. A bending load is applied at a constant loading rate (0.5 mm / min) until the specimen breaks. The maximum load is recorded, and the flexural strength (unit: MPa) is calculated.

[0049] Thermal conductivity test: According to GB / T 10295-2008 "Determination of Steady-State Thermal Resistance and Related Properties of Insulation Materials - Heat Flow Meter Method", the thermal conductivity is calculated by measuring the temperature gradient and heat flux density of the material under steady-state heat flux conditions. The sample is placed in the testing equipment, ensuring good contact with the hot plate. A constant heat flux is applied, and the temperature difference between the two sides of the sample is measured. The thermal conductivity (unit: W / (m·K)) is calculated based on the heat flux density and temperature gradient.

[0050] Fire resistance rating test: According to GB 8624-2012 "Classification of Burning Performance of Building Materials and Products", the sample is placed in a combustion test chamber and ignited. The burning time, flame spread rate, and smoke production are observed. The fire resistance rating is determined based on the test results.

[0051] Example 1

[0052] First, nano-calcite particles were prepared using an alkaline environment (pH maintained at 10-12, sodium hydroxide solution added every hour, stirring at 25°C for 6 hours, standing for 12 hours, centrifuged at 8000 rpm for 2 minutes, and washed three times with deionized water) with aluminum sulfate octahydrate and calcium oxide in a molar ratio of 1:6. Then, nano-calcite particles were prepared for later use. 10g of polyvinyl alcohol particles were dissolved in 90g of deionized water and heated in a 95°C water bath. 1wt% of a surfactant (cocamidopropyl betaine: sodium dodecyl sulfate = 1:1) was dissolved in deionized water and heated in a 50°C water bath. Then, 2wt% of a foam stabilizer (nano-calcite particles: polyvinyl alcohol = 3:1) and 0.5wt% of a silane coupling agent were added, and the mixture was stirred at 50°C for 2 hours.

[0053] The preparation method of the foam stabilizer includes: first, diluting and ultrasonically dispersing the nano-calcite particles for 15 minutes; then, under magnetic stirring at 50°C, adding the nano-calcite dispersion dropwise to the PVA solution; continuing stirring for 1-2 hours to ensure uniform mixing; and then performing a second ultrasonic treatment for 5 minutes to further eliminate agglomeration.

[0054] Water, cement, fly ash, foaming agent, and glass fiber are mixed in a mass ratio of 0.45:1:0.25:0.01:0.006. Weigh each material according to the mix proportion. First, add half cement and half fly ash, then add all the water and stir briefly. Mix the remaining materials (cement, fly ash, and glass fiber), then pour half of this mixture into a mixer and stir for 2 minutes. After stirring, turn over the bottom of the mixture, add the remaining materials, and continue stirring for 4 minutes. Simultaneously, use a foaming machine to foam the foaming agent. Add the resulting foam to the fiber cement slurry and mix thoroughly to obtain glass fiber foamed concrete slurry.

[0055] Brush release oil onto the mold surface, pour the aforementioned glass fiber foamed concrete slurry into the mold, smoothing the surface. Under standard curing conditions, initial curing takes 1-2 days, followed by demolding and a further 5-7 days for mid-term curing, yielding the glass fiber reinforced foamed concrete core material. Experiments were conducted on the prepared foamed concrete material. A portion of the material was removed and placed into a specimen mold to prepare two sets of 40mm×40mm×160mm samples. The glass fiber reinforced foamed concrete core material was wrapped with heat-shrink film to form a pre-assembled core panel. The core material was then wrapped with an airtight bag, with pre-reserved edges at both ends. These pre-reserved edges were folded over and adhered to the surface of the core panel formed by the airtight bag.

[0056] Example 2

[0057] First, nano-sized calcite particles were prepared in an alkaline environment using aluminum sulfate octadecylhydrate and calcium oxide in a molar ratio of 1:6, along with 1 wt% sodium hexametaphosphate surfactant. Then, 10 g of polyvinyl alcohol particles were dissolved in 90 g of deionized water and heated in a 95°C water bath. Next, 1 wt% of a surfactant (cocamidopropyl betaine: sodium dodecyl sulfate = 1:1) was dissolved in deionized water and heated in a 50°C water bath. Then, 2 wt% of a foam stabilizer (nano-sized calcite particles: polyvinyl alcohol = 1:1) and 0.5 wt% of a silane coupling agent were added, and the mixture was stirred at 50°C for 2 hours.

[0058] Water, cement, fly ash, foaming agent, and glass fiber are mixed in a ratio of 0.45:1:0.25:0.01:0.006. Weigh each material according to the mix proportion. First, add half cement and half fly ash, then add all the water and stir briefly. Mix the remaining materials, then pour half of the mixture into a mixer and stir for 2 minutes. After stirring, turn over the bottom of the mixture, add the remaining materials, and continue stirring for 4 minutes. Simultaneously, use a foaming machine to foam the foaming agent. Add the resulting foam to the fiber cement slurry and mix thoroughly to obtain glass fiber foamed concrete slurry.

[0059] Brush release oil onto the mold surface, pour the aforementioned glass fiber foamed concrete slurry into the mold, smoothing the surface. Under standard curing conditions, initial curing takes 1-2 days, followed by demolding and a further 5-7 days for mid-term curing, yielding the glass fiber reinforced foamed concrete core material. Experiments were conducted on the prepared foamed concrete material. A portion of the material was removed and placed into a specimen mold to prepare two sets of 40mm×40mm×160mm samples. The glass fiber reinforced foamed concrete core material was wrapped with heat-shrink film to form a pre-assembled core panel. The core material was then wrapped with an airtight bag, with pre-reserved edges at both ends. These pre-reserved edges were folded over and adhered to the surface of the core panel formed by the airtight bag.

[0060] Example 3

[0061] First, nano-sized calcite particles were prepared in an alkaline environment using aluminum sulfate octadecylhydrate and calcium oxide in a molar ratio of 1:6, along with 1 wt% sodium hexametaphosphate surfactant. Then, 10 g of polyvinyl alcohol particles were dissolved in 90 g of deionized water and heated in a 95°C water bath. Next, 1 wt% of a surfactant (cocamidopropyl betaine: sodium dodecyl sulfate = 1:1) was dissolved in deionized water and heated in a 50°C water bath. Then, 2 wt% of a foam stabilizer (nano-sized calcite particles: polyvinyl alcohol = 1:3) and 0.5 wt% of a silane coupling agent were added, and the mixture was stirred at 50°C for 2 hours.

[0062] Water, cement, fly ash, foaming agent, and glass fiber are mixed in a ratio of 0.45:1:0.25:0.01:0.006. Weigh each material according to the mix proportion. First, add half cement and half fly ash, then add all the water and stir briefly. Mix the remaining materials, then pour half of the mixture into a mixer and stir for 2 minutes. After stirring, turn over the bottom of the mixture, add the remaining materials, and continue stirring for 4 minutes. Simultaneously, use a foaming machine to foam the foaming agent. Add the resulting foam to the fiber cement slurry and mix thoroughly to obtain glass fiber foamed concrete slurry.

[0063] Brush release oil onto the mold surface, pour the aforementioned glass fiber foamed concrete slurry into the mold, smoothing the surface. Under standard curing conditions, initial curing takes 1-2 days, followed by demolding and a further 5-7 days for mid-term curing, yielding the glass fiber reinforced foamed concrete core material. Experiments were conducted on the prepared foamed concrete material. A portion of the material was removed and placed into a specimen mold to prepare two sets of 40mm×40mm×160mm samples. The glass fiber reinforced foamed concrete core material was wrapped with heat-shrink film to form a pre-assembled core panel. The core material was then wrapped with an airtight bag, with pre-reserved edges at both ends. These pre-reserved edges were folded over and adhered to the surface of the core panel formed by the airtight bag.

[0064] Example 4

[0065] First, nano-sized calcite particles were prepared in an alkaline environment using aluminum sulfate octadecylhydrate and calcium oxide in a molar ratio of 1:6, along with 1 wt% sodium hexametaphosphate surfactant. Then, 10 g of polyvinyl alcohol particles were dissolved in 90 g of deionized water and heated in a 95°C water bath. Next, 1 wt% of a surfactant (cocamidopropyl betaine: sodium dodecyl sulfate = 3:1) was dissolved in deionized water and heated in a 50°C water bath. Then, 2 wt% of a foam stabilizer (nano-sized calcite particles: polyvinyl alcohol = 1:1) and 0.5 wt% of a silane coupling agent were added, and the mixture was stirred at 50°C for 2 hours.

[0066] Water, cement, fly ash, foaming agent, and glass fiber are mixed in a ratio of 0.45:1:0.25:0.01:0.006. Weigh each material according to the mix proportion. First, add half cement and half fly ash, then add all the water and stir briefly. Mix the remaining materials, then pour half of the mixture into a mixer and stir for 2 minutes. After stirring, turn over the bottom of the mixture, add the remaining materials, and continue stirring for 4 minutes. Simultaneously, use a foaming machine to foam the foaming agent. Add the resulting foam to the fiber cement slurry and mix thoroughly to obtain glass fiber foamed concrete slurry.

[0067] Brush release oil onto the mold surface, pour the aforementioned glass fiber foamed concrete slurry into the mold, smoothing the surface. Under standard curing conditions, initial curing takes 1-2 days, followed by demolding and a further 5-7 days for mid-term curing, yielding the glass fiber reinforced foamed concrete core material. Experiments were conducted on the prepared foamed concrete material. A portion of the material was removed and placed into a specimen mold to prepare two sets of 40mm×40mm×160mm samples. The glass fiber reinforced foamed concrete core material was wrapped with heat-shrink film to form a pre-assembled core panel. The core material was then wrapped with an airtight bag, with pre-reserved edges at both ends. These pre-reserved edges were folded over and adhered to the surface of the core panel formed by the airtight bag.

[0068] Example 5

[0069] First, nano-sized calcite particles were prepared in an alkaline environment using aluminum sulfate octadecylhydrate and calcium oxide in a molar ratio of 1:6, along with 1 wt% sodium hexametaphosphate surfactant. Then, 10 g of polyvinyl alcohol particles were dissolved in 90 g of deionized water and heated in a 95°C water bath. Next, 1 wt% of a surfactant (cocamidopropyl betaine: sodium dodecyl sulfate = 1:3) was dissolved in deionized water and heated in a 50°C water bath. Then, 2 wt% of a foam stabilizer (nano-sized calcite particles: polyvinyl alcohol = 1:1) and 0.5 wt% of a silane coupling agent were added, and the mixture was stirred at 50°C for 2 hours.

[0070] Water, cement, fly ash, foaming agent, and glass fiber are mixed in a ratio of 0.45:1:0.25:0.01:0.006. Weigh each material according to the mix proportion. First, add half cement and half fly ash, then add all the water and stir briefly. Mix the remaining materials, then pour half of the mixture into a mixer and stir for 2 minutes. After stirring, turn over the bottom of the mixture, add the remaining materials, and continue stirring for 4 minutes. Simultaneously, use a foaming machine to foam the foaming agent. Add the resulting foam to the fiber cement slurry and mix thoroughly to obtain glass fiber foamed concrete slurry.

[0071] Brush release oil onto the mold surface, pour the aforementioned glass fiber foamed concrete slurry into the mold, smoothing the surface. Under standard curing conditions, initial curing takes 1-2 days, followed by demolding and a further 5-7 days for mid-term curing, yielding the glass fiber reinforced foamed concrete core material. Experiments were conducted on the prepared foamed concrete material. A portion of the material was removed and placed into a specimen mold to prepare two sets of 40mm×40mm×160mm samples. The glass fiber reinforced foamed concrete core material was wrapped with heat-shrink film to form a pre-assembled core panel. The core material was then wrapped with an airtight bag, with pre-reserved edges at both ends. These pre-reserved edges were folded over and adhered to the surface of the core panel formed by the airtight bag.

[0072] Comparative Example 1

[0073] First, nano-sized calcite particles were prepared in an alkaline environment using aluminum sulfate octahydrate and calcium oxide in a molar ratio of 1:6 and 1 wt% sodium hexametaphosphate as a surfactant. Then, 10 g of polyvinyl alcohol particles were dissolved in 90 g of deionized water and heated in a 95°C water bath. Next, 1 wt% of a surfactant (cocamidopropyl betaine: sodium dodecyl sulfate = 1:1) was dissolved in deionized water and heated in a 50°C water bath. Then, 2 wt% of a foam stabilizer (nano-sized calcite particles: polyvinyl alcohol = 1:0) and 0.5 wt% of a silane coupling agent were added, and the mixture was stirred at 50°C for 2 hours.

[0074] Water, cement, fly ash, foaming agent, and glass fiber are mixed in a ratio of 0.45:1:0.25:0.01:0.006. Weigh each material according to the mix proportion. First, add half cement and half fly ash, then add all the water and stir briefly. Mix the remaining materials, then pour half of the mixture into a mixer and stir for 2 minutes. After stirring, turn over the bottom of the mixture, add the remaining materials, and continue stirring for 4 minutes. Simultaneously, use a foaming machine to foam the foaming agent. Add the resulting foam to the fiber cement slurry and mix thoroughly to obtain glass fiber foamed concrete slurry.

[0075] Brush release oil onto the mold surface, pour the aforementioned glass fiber foamed concrete slurry into the mold, smoothing the surface. Under standard curing conditions, initial curing takes 1-2 days, followed by demolding and a further 5-7 days for mid-term curing, yielding the glass fiber reinforced foamed concrete core material. Experiments were conducted on the prepared foamed concrete material. A portion of the material was removed and placed into a specimen mold to prepare two sets of 40mm×40mm×160mm samples. The glass fiber reinforced foamed concrete core material was wrapped with heat-shrink film to form a pre-assembled core panel. The core material was then wrapped with an airtight bag, with pre-reserved edges at both ends. These pre-reserved edges were folded over and adhered to the surface of the core panel formed by the airtight bag.

[0076] Comparative Example 2

[0077] First, nano-sized calcite particles were prepared using an alkaline environment with aluminum sulfate octahydrate and calcium oxide in a molar ratio of 1:6 and 1 wt% sodium hexametaphosphate as a surfactant. Then, 10 g of polyvinyl alcohol particles were dissolved in 90 g of deionized water and heated in a 95°C water bath. Next, 1 wt% of a surfactant (cocamidopropyl betaine: sodium dodecyl sulfate = 1:1) was dissolved in deionized water and heated in a 50°C water bath. Then, 2 wt% of a foam stabilizer (nano-sized calcite particles: polyvinyl alcohol = 0:1) and 0.5 wt% of a silane coupling agent were added, and the mixture was stirred at 50°C for 2 hours.

[0078] Water, cement, fly ash, foaming agent, and glass fiber are mixed in a ratio of 0.45:1:0.25:0.01:0.006. Weigh each material according to the mix proportion. First, add half cement and half fly ash, then add all the water and stir briefly. Mix the remaining materials, then pour half of the mixture into a mixer and stir for 2 minutes. After stirring, turn over the bottom of the mixture, add the remaining materials, and continue stirring for 4 minutes. Simultaneously, use a foaming machine to foam the foaming agent. Add the resulting foam to the fiber cement slurry and mix thoroughly to obtain glass fiber foamed concrete slurry.

[0079] Brush release oil onto the mold surface, pour the aforementioned glass fiber foamed concrete slurry into the mold, smoothing the surface. Under standard curing conditions, initial curing takes 1-2 days, followed by demolding and a further 5-7 days for mid-term curing, yielding the glass fiber reinforced foamed concrete core material. Experiments were conducted on the prepared foamed concrete material. A portion of the material was removed and placed into a specimen mold to prepare two sets of 40mm×40mm×160mm samples. The glass fiber reinforced foamed concrete core material was wrapped with heat-shrink film to form a pre-assembled core panel. The core material was then wrapped with an airtight bag, with pre-reserved edges at both ends. These pre-reserved edges were folded over and adhered to the surface of the core panel formed by the airtight bag.

[0080] Comparative Example 3

[0081] First, nano-sized calcite particles were prepared in an alkaline environment using aluminum sulfate octadecylhydrate and calcium oxide in a molar ratio of 1:6, along with 1 wt% sodium hexametaphosphate surfactant. Then, 10 g of polyvinyl alcohol particles were dissolved in 90 g of deionized water and heated in a 95°C water bath. Next, 1 wt% of a surfactant (cocamidopropyl betaine: sodium dodecyl sulfate = 1:1) was dissolved in deionized water and heated in a 50°C water bath. Then, 2 wt% of a foam stabilizer (nano-sized calcite particles: polyvinyl alcohol = 1:1) and 0.5 wt% of a silane coupling agent were added, and the mixture was stirred at 50°C for 2 hours.

[0082] Water, cement, fly ash, foaming agent, and glass fiber are mixed in a ratio of 0.45:1:0.25:0.01:0.006. Weigh each material according to the mix proportion. First, add half cement and half fly ash, then add all the water and stir briefly. Mix the remaining materials, then pour half of the mixture into a mixer and stir for 2 minutes. After stirring, turn over the bottom of the mixture, add the remaining materials, and continue stirring for 4 minutes. Simultaneously, use a foaming machine to foam the foaming agent. Add the resulting foam to the fiber cement slurry and mix thoroughly to obtain glass fiber foamed concrete slurry.

[0083] Brush release oil onto the mold surface, pour the aforementioned glass fiber foamed concrete slurry into the mold, ensuring a smooth surface. Under standard curing conditions, initial curing takes 1-2 days, followed by demolding and a further 5-7 days for intermediate curing, yielding the glass fiber reinforced foamed concrete core material. Experiments were conducted on the prepared foamed concrete material without wrapping it in heat-shrink film or airtight packaging bags.

[0084] Table 1. Performance test results of the examples and comparative examples.

[0085]

[0086]

[0087] Comparing Examples 2, 4, and 5, when the ratio of nano-calcite particles to polyvinyl alcohol in the foam stabilizer is 1:1, and the ratio of cocamidopropyl betaine to sodium dodecyl sulfate is 1:1 (Example 2), the insulation board exhibits relatively high compressive, tensile, and flexural strengths, and a low thermal conductivity. This indicates that at this ratio, the synergistic effect of the two surfactants is optimal, effectively reducing the surface tension at the gas-liquid interface, forming a stable foam structure, improving the density and uniformity of the foamed concrete, and thus enhancing the mechanical and thermal insulation properties of the insulation board. Comparing Examples 1, 2, and 3, when the ratio of surfactants cocamidopropyl betaine to sodium dodecyl sulfate is 1:1, and the ratio of nano-calcite particles to polyvinyl alcohol is 1:1 (Example 2), all performance characteristics are optimal. This demonstrates that at this ratio, inorganic nano-calcite particles and organic polyvinyl alcohol exert a good synergistic foam-stabilizing effect. Nano-sized calcite particles increase the strength and elasticity of the liquid film, while polyvinyl alcohol reduces the drainage rate of the liquid film, jointly stabilizing the foam and making the pore structure of the foamed concrete uniform, thus enhancing the overall performance of the insulation board. Comparative Example 1 used only nano-sized calcite particles as a foam stabilizer, and Comparative Example 2 used only polyvinyl alcohol as a foam stabilizer; the mechanical properties of both were lower than those of Example 2. This indicates that a single foam stabilizer cannot effectively stabilize the foam like a composite foam stabilizer, making it difficult to form a uniform and dense foamed concrete structure, leading to a decrease in the mechanical properties of the insulation board, demonstrating the advantages of organic-inorganic composite foam stabilizers. Comparative Example 3 did not use heat-shrink film or airtight wrapping bags, and its thermal conductivity was significantly higher than that of the examples. Heat-shrink film and airtight wrapping bags can effectively prevent heat transfer, and the vacuum-sealed structure reduces gas convection, improving insulation performance. This shows that the structural design of the insulation board of the present invention is crucial for reducing thermal conductivity and improving insulation effect. It can be seen that Example 2 is the optimal formulation.

[0088] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A foaming agent for foamed concrete, characterized in that, It is composed of the following raw materials in weight percentages: surfactant 1-1.5wt%, foam stabilizer 2-2.5wt%, silane coupling agent 0.5-1wt%, and the remainder is water; The foam stabilizer is composed of nano-calcite particles and polyvinyl alcohol, with the ratio of nano-calcite to polyvinyl alcohol being 1:

1. The surfactant is composed of cocamidopropyl betaine and sodium dodecyl sulfate in a ratio of 1:

1.

2. The method for preparing the foamed concrete foaming agent as described in claim 1, characterized in that, include; Heat the surfactant solution to a predetermined temperature, add the foam stabilizer, mix well, then add the silane coupling agent and mix well to obtain the final product.

3. The method for preparing the foamed concrete foaming agent as described in claim 2, characterized in that, The foam stabilizer is composed of nano-calcite particles and polyvinyl alcohol solution.

4. The method for preparing the foamed concrete foaming agent as described in claim 2, characterized in that, The preparation method of the nano-calcite particles includes: preparing them with aluminum sulfate octadechydrate, calcium oxide, and the surfactant sodium hexametaphosphate in an alkaline environment, wherein the molar ratio of aluminum sulfate octadechydrate to calcium oxide is 1:6-8, the mass fraction of sodium hexametaphosphate is 1-1.5wt%, and the pH is maintained at 10-12 during the preparation process.

5. The application of the foamed concrete foaming agent according to claim 1 in the preparation of fiber-reinforced foamed concrete vacuum insulation board.

6. A fiber-reinforced foamed concrete vacuum insulation board, characterized in that, include: The components include a glass fiber reinforced foamed concrete core, a heat-shrinkable film, and an airtight wrapping bag. The heat-shrinkable film has multiple air vents and is wrapped around the foamed concrete core to form a pre-assembled core panel. The pre-assembled core panel is vacuum-sealed by the airtight wrapping bag. The airtight wrapping bag has pre-reserved edges at both ends, which are folded over and pasted onto the surface of the panel formed by the airtight wrapping bag. The glass fiber reinforced foamed concrete core material is composed of the following raw materials in parts by weight: 0.45-0.5 parts water, 1-1.2 parts cement, 0.25-0.3 parts fly ash, 0.01-0.012 parts foamed concrete foaming agent as described in claim 1, and 0.006-0.008 parts glass fiber.

7. The fiber-reinforced foamed concrete insulation board according to claim 6, characterized in that, The heat shrink film has multiple circular protrusions on its surface and multiple air pores, which wrap around the core material.

8. A method for preparing a fiber-reinforced foamed concrete vacuum insulation board as described in claim 6, characterized in that, include: Take a portion of cement, a portion of fly ash, and all of the water, mix them evenly, and you will get a slurry; Mix the remaining materials thoroughly to obtain the mixture; Take a portion of the mixture and add it to the slurry, mix well, then add the remaining mixture and mix well to obtain fiber cement slurry; The foaming agent is foamed, and the resulting foam is added to the fiber cement slurry and mixed evenly to obtain glass fiber foam concrete slurry. The glass fiber foamed concrete slurry is poured into a mold, cured, and demolded to obtain glass fiber reinforced foamed concrete core material. A pre-assembled core panel is formed by wrapping glass fiber reinforced foamed concrete core material with heat shrink film. The pre-assembled core is wrapped in an airtight bag, with process-reserved edges formed at both ends of the airtight bag. These process-reserved edges are then folded over and pasted onto the surface of the core formed by the airtight bag.

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