Light prefabricated concrete wallboard and production method thereof

Abstract

The invention belongs to the technical field of building materials, and particularly relates to a light prefabricated concrete wallboard and a production method thereof. The light prefabricated concrete wallboard is prepared by coating the main component fly ash of the concrete wallboard and cooperating with the combined action of the carbon nanotubes and the basalt fibers, so that the compressive strength of the material is effectively improved, the impact resistance is improved, and meanwhile, good combustion performance is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials, and particularly relates to a lightweight prefabricated concrete wallboard and a production method thereof. Background Art

[0002] Lightweight precast concrete wall panels are a commonly used building material in modern buildings. They have the advantages of light weight, high strength, and convenient construction. This type of wall panel is prefabricated in the factory and then transported to the construction site for installation, which can greatly improve construction efficiency and reduce on-site wet operations. Lightweight precast concrete wall panels have the characteristics of light weight, good thermal insulation, good sound insulation, superior fire resistance, convenient and fast construction, and environmental protection and energy saving. They are widely used in residential, commercial and industrial buildings and are particularly suitable for projects with high requirements for building energy conservation.

[0003] A Chinese patent (publication number CN115506536B) discloses a lightweight reinforced ceramsite concrete wallboard and its preparation process. The invention uses ceramsite, ceramic sand, and fly ash as the main raw materials, and adds cement, water reducer, fiber material, foaming agent, cellulose, carbon nanotubes loaded with composite materials, and water as auxiliary materials to prepare the wallboard; wherein the carbon nanotubes loaded with composite materials are obtained by compounding microcapsule adhesives coated with perlite, titanium dioxide, and carbon nanotube oxides; added to the ceramsite concrete slurry, the mechanical properties and thermal insulation properties of the wallboard are enhanced. However, the concrete wallboard in the prior art still has problems such as insufficient compressive strength, the need to improve the impact resistance, and poor combustion performance, which affect its further promotion and application.

[0004] Therefore, there is an urgent need for a lightweight prefabricated concrete wall panel, which can effectively increase the compressive strength of the material, improve the impact resistance, and obtain good combustion performance by modifying the main components of the concrete wall panel. Summary of the invention

[0005] The purpose of the present invention is to provide a lightweight precast concrete wall panel and a production method thereof. By coating fly ash, the main component of the concrete wall panel, and cooperating with carbon nanotubes and basalt fibers, a lightweight precast concrete wall panel is prepared, which effectively increases the compressive strength of the material, improves the impact resistance, and obtains good combustion performance.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A first aspect of the present invention provides a method for producing a lightweight prefabricated concrete wall panel, comprising the following steps:

[0008] S1: Add 180 - 220 parts by weight of fly ash into 2800 - 3200 parts of deionized water and stir. Then add 6 - 8 parts of 0.4 - 0.6 mol / L antimony trichloride solution, 60 - 80 parts of 0.4 - 0.6 mol / L tin tetrachloride solution and 2 - 4 parts of sodium hydroxide for coating treatment to obtain fly ash composite powder.

[0009] S2: Mix 160 - 200 parts of cement, 180 - 220 parts of fly ash composite powder, 16 - 20 parts of modified carbon nanotubes, 8 - 16 parts of compound modified basalt fibers, 3 - 5 parts of water reducing agent and 1.4 - 1.8 parts of hydroxypropyl methylcellulose. Then add 180 - 220 parts of ceramsite, 3.6 - 4.2 parts of α - olefin sulfonate and 350 - 360 parts of water and stir to obtain a slurry. Fix the steel bar welded mesh and polystyrene foam board, use the slurry to cast the wall panel, vibrate it compactly, cure and form to obtain a lightweight precast concrete wall panel.

[0010] As a preferred solution, the weight parts of the cement in the present invention can be 160 parts, 170 parts, 180 parts, 190 parts or 200 parts, etc.

[0011] As a preferred solution, the weight parts of the modified carbon nanotubes in the present invention can be 16 parts, 17 parts, 18 parts, 19 parts or 20 parts, etc.

[0012] As a preferred solution, the weight parts of the compound modified basalt fibers in the present invention can be 8 parts, 10 parts, 12 parts, 14 parts or 16 parts, etc.

[0013] As a preferred solution, the weight parts of the water reducing agent in the present invention can be 3 parts, 3.5 parts, 4 parts, 4.5 parts or 5 parts, etc.

[0014] As a preferred solution, the weight parts of the hydroxypropyl methylcellulose in the present invention can be 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts or 1.8 parts, etc.

[0015] As a preferred solution, the weight parts of the ceramsite in the present invention can be 180 parts, 190 parts, 200 parts, 210 parts or 220 parts, etc.

[0016] As a preferred solution, the weight parts of the α - olefin sulfonate in the present invention can be 3.6 parts, 3.7 parts, 3.8 parts, 3.9 parts, 4.0 parts, 4.1 parts or 4.2 parts, etc.

[0017] As a preferred solution, the conditions of the coating treatment include: adjust the pH to 4.2 - 4.6 for coating for 40 - 60 min, wash with water, filter, dry, and calcine.

[0018] As a preferred solution, the conditions for the calcination include: the calcination temperature is 680 - 700 °C, and the calcination time is 120 - 140 min.

[0019] The fly ash composite powder can be improved in the interfacial bonding force between fly ash particles and the cement matrix through coating with nanoscale antimony-doped tin oxide, effectively reducing the occurrence of microcracks, thereby enhancing the stability of the overall structure; meanwhile, the antimony-doped tin oxide coating layer can fill some tiny pores on the surface of fly ash, making the composite material more dense, reducing the existence of harmful pores, and improving the overall compressive strength of the material.

[0020] As a preferred solution, the preparation method of the modified carbon nanotubes includes: by weight, adding 16 - 20 parts of carbon nanotubes and 4 - 6 parts of boron oxide into 90 - 100 parts of absolute ethanol, ultrasonically dispersing them evenly, and then performing high-temperature calcination to obtain boron-containing carbon nanotubes; subjecting the boron-containing carbon nanotubes to carboxylation treatment to obtain modified carbon nanotubes.

[0021] As a preferred solution, the tube length of the carbon nanotubes is 5 - 15 μm.

[0022] As a preferred solution, the conditions for the high-temperature calcination include: first heating to 80 - 90 °C to remove absolute ethanol, then transferring to an atmosphere furnace, heating to 1200 - 1400 °C under argon protection and holding for 3 - 5 h, cooling to room temperature, washing with hot water, and drying.

[0023] As a preferred solution, the conditions for the carboxylation treatment include: first wetting 16 - 20 parts of boron-containing carbon nanotubes with absolute ethanol, then adding 200 - 300 parts of a sulfuric acid solution with a mass concentration of 10 - 20%, stirring at 80 - 90 °C for 5 - 7 h, cooling to room temperature, then adding 20 - 30 parts of nitric acid and stirring for 20 - 24 h, washing with water until the pH is neutral, and drying.

[0024] When subjected to impact loads, microcracks are likely to occur inside the concrete. Due to the extremely high aspect ratio and good flexibility of the modified carbon nanotubes, they can form "bridges" between these microcracks to prevent the cracks from further expanding; meanwhile, boron doping can improve the interfacial interaction between the carbon nanotubes and the cement matrix, enabling a stronger bonding force to be formed between the two, thereby enhancing the impact resistance of the overall structure.

[0025] As a preferred solution, the preparation method of the compound modified basalt fiber includes: by weight, first pretreat 8-16 parts of commercially available basalt fiber, and then add it to 160-200 parts of an aqueous solution of cetyltrimethylammonium bromide with a mass concentration of 0.6-0.8% for cationic modification to obtain cation-modified basalt fiber; subject the cation-modified basalt fiber to coupling modification to obtain compound modified basalt fiber.

[0026] As a preferred solution, the conditions of the pretreatment include: first place it in a muffle furnace for heat treatment at 480-500°C for 50-60 min, soak it in a hydrochloric acid solution of 0.8-1.2 mol / L for pickling at 70-80°C for 4-6 h after cooling, and wash it with deionized water until the pH is neutral.

[0027] As a preferred solution, the conditions of the cationic modification include: impregnate at 60-70°C for 6-8 h, filter, wash with water, and dry.

[0028] As a preferred solution, the conditions of the coupling modification include: mix 80-90 parts of absolute ethanol and 10-20 parts of deionized water evenly, then add 0.6-0.8 parts of silane coupling agent KH602 and stir at 60-70°C for 20-30 min, then add 8-16 parts of the cation-modified basalt fiber and soak for 6-8 h, filter, wash with absolute ethanol, and dry at 80-90°C for 10-12 h.

[0029] The compound modified basalt fiber has a low thermal conductivity. During the combustion process, the basalt fiber cuts off the heat propagation inside the material, thereby slowing down the decomposition rate of combustible gases in the unburned area; at the same time, the basalt fiber can promote the densification of the carbon layer on the material surface and prevent the release of combustible gases.

[0030] The second aspect of the present invention provides a lightweight precast concrete wall panel prepared by the method described in the first aspect.

[0031] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0032] 1. The modified carbon nanotubes of the present invention introduce carboxyl groups through acidification treatment. The oxygen atoms in the carboxyl groups have lone pairs of electrons and can form surface complexes with metal ions on the surface of the fly ash composite powder. At the same time, the compound modified basalt fiber introduces amino groups through silane coupling agent KH602 and can combine with the amino groups of the modified carbon nanotubes, thereby constructing a high-density network structure. The compressive strength and impact resistance of the concrete wall panel are effectively improved through the network structure.

[0033] 2. The antimony-doped tin oxide in the fly ash composite powder of the present invention has high thermal stability and chemical stability. It can improve the heat resistance of the substrate and reduce the decomposition rate of the material at high temperatures. At the same time, antimony compounds can promote the formation of a carbon layer, slowing down or preventing further combustion. The boron element introduced by the modified carbon nanotubes can capture free radicals generated during combustion at high temperatures, interrupting the chain reaction and inhibiting combustion. The compound-modified basalt fiber has a low thermal conductivity. During combustion, the basalt fiber cuts off the heat propagation inside the material, thereby slowing down the decomposition rate of combustible gases in the unburned area. Through the synergistic effect of multiple components, the combustion performance of the concrete wall panel is effectively improved.

[0034] 3. The fly ash composite powder of the present invention can be coated with nanoscale antimony-doped tin oxide, which can improve the interfacial bonding force between fly ash particles and the cement matrix, effectively reduce the occurrence of microcracks, and thus improve the stability of the overall structure. At the same time, the antimony-doped tin oxide coating layer can fill some small pores on the surface of fly ash, making the composite material more dense, reducing the existence of harmful pores, and improving the overall compressive strength of the material.

[0035] 4. The modified carbon nanotubes of the present invention have an extremely high aspect ratio and good flexibility, and can form "bridges" between microcracks to prevent further crack propagation. At the same time, boron doping can improve the interfacial interaction between carbon nanotubes and the cement matrix, forming a stronger bonding force between the two, thereby improving the impact resistance of the overall structure.

[0036] 5. The compound-modified basalt fiber of the present invention has a low thermal conductivity. During combustion, the basalt fiber cuts off the heat propagation inside the material, thereby slowing down the decomposition rate of combustible gases in the unburned area. At the same time, the basalt fiber can promote the densification of the carbon layer on the material surface to prevent the release of combustible gases. Detailed Embodiments

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0038] The sources of some components in the examples and comparative examples are as follows:

[0039] Cement, product number WD3042, purchased from Hubei Wande Chemical Co., Ltd.

[0040] Ceramsite, purchased from Nanjing Yongjie New Building Materials Co., Ltd.

[0041] Commercially available fly ash, purchased from Nanjing Yongjie New Building Materials Co., Ltd.

[0042] Commercially available carbon nanotubes Ⅰ, model FT9000, tube length 10 μm, purchased from Jiangsu Tiannai Technology Co., Ltd.;

[0043] Commercially available carbon nanotubes Ⅱ, model FT6000, tube length 100 μm, purchased from Jiangsu Tiannai Technology Co., Ltd.;

[0044] Commercially available basalt fibers, purchased from Jiangsu Tianlong Basalt Fiber Co., Ltd.;

[0045] Naphthalene series water reducing agent, product number JSJ02, purchased from Jinan Shanha Chemical Technology Co., Ltd.;

[0046] Sodium α-olefin sulfonate, CAS No. 68439-57-6, purchased from Shanghai Macklin Biochemical Co., Ltd.;

[0047] Hydroxypropyl methylcellulose, CAS No. 9004-65-3, purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0048] Tin tetrachloride, CAS No. 10026-06-9, purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0049] Antimony trichloride, CAS No. 10025-91-9, purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0050] Boron oxide, CAS No. 1303-86-2, purchased from Shanghai Macklin Biochemical Co., Ltd.;

[0051] Cetyltrimethylammonium bromide, CAS No. 57-09-0, purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0052] Silane coupling agent KH602, CAS No. 3069-29-2, purchased from Guangzhou Jucheng Zhaoye Organosilicon Raw Materials Co., Ltd.

[0053] Example 1

[0054] This example provides a production method of a lightweight precast concrete wall panel, including the following steps:

[0055] S1: By weight, add 220 parts of fly ash to 3200 parts of deionized water and stir to mix, then add 8 parts of 0.4 mol / L antimony trichloride solution, 80 parts of 0.4 mol / L tin tetrachloride solution and 4 parts of sodium hydroxide for coating treatment (specifically: first mix the antimony trichloride solution, tin tetrachloride solution and sodium hydroxide evenly, then dropwise add at a speed of 1 mL / min, and adjust the pH to 4.6 after dropping for coating for 60 min), wash with water, filter, dry, and calcine (temperature is 700 °C, time is 120 min) to obtain fly ash composite powder;

[0056] S2: Mix 200 parts of cement, 220 parts of fly ash composite powder, 20 parts of modified carbon nanotubes, 16 parts of compound modified basalt fibers, 5 parts of water reducing agent and 1.8 parts of hydroxypropyl methylcellulose evenly, then add 220 parts of ceramsite, 4.2 parts of α-olefin sulfonate and 360 parts of water and stir evenly to obtain a slurry. Fix the steel bar welded mesh and polystyrene foam board, use the slurry to cast the wallboard, vibrate it densely, cure and form to obtain a lightweight precast concrete wallboard.

[0057] Preparation of the modified carbon nanotubes: By weight, add 20 parts of commercially available carbon nanotubes I (model FT9000, tube length 10 μm) and 6 parts of boron oxide to 100 parts of absolute ethanol and disperse evenly by ultrasonic treatment, then conduct high-temperature calcination. First, heat to 90 °C to remove the absolute ethanol, then transfer to an atmosphere furnace, heat up to 1400 °C under argon protection and hold for 3 h, cool to room temperature, wash with hot water, and dry to obtain boron-containing carbon nanotubes; first wet 20 parts of the boron-containing carbon nanotubes with absolute ethanol, then add 300 parts of a sulfuric acid solution with a mass concentration of 10%, stir at 90 °C for 5 h, after cooling to room temperature, add 30 parts of a nitric acid solution with a mass concentration of 50% and stir for 24 h, wash with water until the pH is neutral, and dry to obtain modified carbon nanotubes.

[0058] Preparation of the compound modified basalt fibers: By weight, first pretreat 16 parts of commercially available basalt fibers. First, place them in a muffle furnace and heat-treat at 500 °C for 50 min. After cooling, soak them in a 1.2 mol / L hydrochloric acid solution and conduct acid pickling at 80 °C for 4 h, wash with deionized water until the pH is neutral, then add them to 200 parts of an aqueous solution of cetyltrimethylammonium bromide with a mass concentration of 0.6% for cationic modification, impregnate at 70 °C for 6 h, filter, wash with water, and dry to obtain cationically modified basalt fibers; mix 90 parts of absolute ethanol and 10 parts of deionized water evenly, then add 0.8 part of silane coupling agent KH602 and stir at 70 °C for 20 min, then add 16 parts of the cationically modified basalt fibers and soak for 8 h, filter, wash with absolute ethanol, and dry at 90 °C for 10 h to obtain compound modified basalt fibers.

[0059] Example 2

[0060] This example provides a production method for a lightweight precast concrete wallboard, including the following steps:

[0061] S1: By weight, 180 parts of fly ash are added to 2800 parts of deionized water and stirred and mixed. Then, 6 parts of 0.6 mol / L antimony trichloride solution, 60 parts of 0.6 mol / L tin tetrachloride solution, and 2 parts of sodium hydroxide are added for coating treatment (specifically: first, the antimony trichloride solution, tin tetrachloride solution, and sodium hydroxide are mixed evenly, and then dropped at a speed of 1 mL / min. After the dropping is completed, the pH is adjusted to 4.2 for coating for 40 min), washed with water, filtered, dried, and calcined (temperature: 680 °C, time: 140 min) to obtain fly ash composite powder;

[0062] S2: 160 parts of cement, 180 parts of fly ash composite powder, 16 parts of modified carbon nanotubes, 8 parts of compound modified basalt fibers, 3 parts of water reducing agent, and 1.4 parts of hydroxypropyl methylcellulose are mixed evenly. Then, 180 parts of ceramsite, 3.6 parts of α-olefin sulfonate, and 350 parts of water are added and stirred evenly to obtain a slurry. The steel bar welded mesh and polystyrene foam board are fixed, and the slurry is used to cast the wall panel, vibrated and compacted, and cured and formed to obtain a lightweight precast concrete wall panel.

[0063] Preparation of the modified carbon nanotubes: By weight, 16 parts of commercially available carbon nanotubes I (model FT9000, tube length: 10 μm) and 4 parts of boron oxide are added to 90 parts of absolute ethanol and ultrasonically dispersed evenly. Then, high-temperature calcination is carried out. First, it is heated to 80 °C to remove absolute ethanol, and then transferred to an atmosphere furnace. Under argon protection, it is heated to 1200 °C and maintained for 5 h, cooled to room temperature, washed with hot water, and dried to obtain boron-containing carbon nanotubes; First, 16 parts of boron-containing carbon nanotubes are wetted with absolute ethanol, and then 200 parts of sulfuric acid solution with a mass concentration of 20% is added, and stirred at 80 °C for 7 h. After cooling to room temperature, 20 parts of nitric acid solution with a mass concentration of 50% is added and stirred for 20 h, washed with water until the pH is neutral, and dried to obtain modified carbon nanotubes.

[0064] Preparation of the compound modified basalt fibers: By weight, first, 8 parts of commercially available basalt fibers are pretreated. First, they are placed in a muffle furnace and heat-treated at 480 °C for 60 min. After cooling, they are soaked in 1.2 mol / L hydrochloric acid solution for pickling at 70 °C for 6 h, washed with deionized water until the pH is neutral, and then added to 160 parts of cetyltrimethylammonium bromide aqueous solution with a mass concentration of 0.6% for cationic modification, impregnated at 60 °C for 8 h, filtered, washed with water, and dried to obtain cationically modified basalt fibers; 80 parts of absolute ethanol and 20 parts of deionized water are mixed evenly, and then 0.6 parts of silane coupling agent KH602 is added and stirred at 60 °C for 30 min. Then, 8 parts of the cationically modified basalt fibers are added and infiltrated for 6 h, filtered, washed with absolute ethanol, and dried at 80 °C for 12 h to obtain compound modified basalt fibers.

[0065] Example 3

[0066] This embodiment provides a production method of a lightweight precast concrete wall panel, including the following steps:

[0067] S1: By weight, add 200 parts of fly ash into 3000 parts of deionized water and stir to mix. Then add 7 parts of 0.5 mol / L antimony trichloride solution, 70 parts of 0.5 mol / L tin tetrachloride solution and 3 parts of sodium hydroxide for coating treatment (specifically: first mix the antimony trichloride solution, tin tetrachloride solution and sodium hydroxide evenly, then dropwise add at a speed of 1 mL / min. After the dropping is completed, adjust the pH to 4.4 for coating for 50 min), wash with water, filter, dry, and calcine (temperature is 690 °C, time is 130 min) to obtain fly ash composite powder;

[0068] S2: Mix 180 parts of cement, 200 parts of fly ash composite powder, 18 parts of modified carbon nanotubes, 12 parts of compound modified basalt fibers, 4 parts of water reducing agent and 1.6 parts of hydroxypropyl methyl cellulose evenly. Then add 200 parts of ceramsite, 3.8 parts of α-olefin sulfonate and 355 parts of water and stir evenly to obtain a slurry. Fix the steel bar welded mesh and polystyrene foam board, use the slurry to pour the wall panel, vibrate it densely, and cure and form to obtain a lightweight precast concrete wall panel.

[0069] Preparation of the modified carbon nanotubes: By weight, add 18 parts of commercially available carbon nanotubes Ⅰ (model FT9000, tube length is 10 μm) and 5 parts of boron oxide into 95 parts of absolute ethanol and disperse them evenly by ultrasonic wave. Then carry out high-temperature calcination. First heat to 85 °C to remove the absolute ethanol, then transfer it to an atmosphere furnace, heat up to 1300 °C under argon protection and keep it for 4 h, cool to room temperature, wash with hot water, and dry to obtain boron-containing carbon nanotubes; First moisten 18 parts of boron-containing carbon nanotubes with absolute ethanol, then add 250 parts of sulfuric acid solution with a mass concentration fraction of 15%, stir at 85 °C for 6 h, cool to room temperature, then add 25 parts of nitric acid solution with a mass concentration fraction of 50% and stir for 22 h, wash with water until the pH is neutral, and dry to obtain modified carbon nanotubes.

[0070] Preparation of the compound modified basalt fiber: By weight, first pre-treat 12 parts of commercially available basalt fiber. First, place it in a muffle furnace and heat-treat it at 490 °C for 55 min. After cooling, soak it in a 1.0 mol / L hydrochloric acid solution and perform acid washing at 75 °C for 5 h. Wash it with deionized water until the pH is neutral. Then add it to 180 parts of an aqueous solution of cetyltrimethylammonium bromide with a mass concentration of 0.7% for cationic modification. Immerse it at 65 °C for 7 h, filter, wash with water, and dry to obtain cationic modified basalt fiber; Mix 85 parts of absolute ethanol and 15 parts of deionized water evenly, then add 0.7 parts of silane coupling agent KH602 and stir at 65 °C for 25 min. Then add 12 parts of the cationic modified basalt fiber and soak for 7 h, filter, wash with absolute ethanol, and dry at 85 °C for 11 h to obtain the compound modified basalt fiber.

[0071] Example 4

[0072] The difference between this example and Example 1 is that commercially available carbon nanotube I (model FT9000) is used to replace the modified carbon nanotube.

[0073] Example 5

[0074] The difference between this example and Example 1 is that commercially available carbon nanotube II (FT6000) is used to replace commercially available carbon nanotube I (model FT9000) for the preparation of the modified carbon nanotube.

[0075] Example 6

[0076] The difference between this example and Example 1 is that commercially available basalt fiber (purchased from Jiangsu Tianlong) is used to replace the compound modified basalt fiber.

[0077] Comparative Example 1

[0078] The difference between this comparative example and Example 1 is that commercially available fly ash (purchased from Nanjing Yongjie) is used to replace the fly ash composite powder.

[0079] Comparative Example 2

[0080] The difference between this comparative example and Example 1 is that 20 parts of the modified carbon nanotube are not added to the components in step S2.

[0081] Comparative Example 3

[0082] The difference between this comparative example and Example 1 is that 16 parts of the compound modified basalt fiber are not added to the components in step S2.

[0083] Performance test

[0084] Perform the following tests on the above examples and comparative examples:

[0085] (1) Compressive strength test: The test was carried out with reference to the requirements of "GB / T 23450-2009 Thermal Insulation Slab for Building Partition Walls".

[0086] (2) Impact resistance test: The test was carried out with reference to the requirements of "GB / T 23450-2009 Thermal Insulation Slab for Building Partition Walls".

[0087] (3) Combustion performance test: The test was carried out with reference to the requirements of "GB 8624-2012 Classification of the Burning Behavior of Building Materials and Products".

[0088] Table 1 Performance test results

[0089]

[0090] From the above performance test results, it can be seen that the comprehensive performance of Examples 1-3 is the best, with a compressive strength of 14.3-14.8 MPa, no cracks on the board surface after 15 impact resistance tests, and a combustion performance of Class A1; this is mainly because the fly ash composite powder is obtained by coating the main component fly ash of the concrete wallboard, and with the combined action of modified carbon nanotubes and compound modified basalt fibers, the compressive strength of the material is effectively increased, the impact resistance performance is improved, and good combustion performance is obtained at the same time.

[0091] Compared with Example 1, in Example 4, commercially available carbon nanotube I (model FT9000) was used to replace the modified carbon nanotubes, resulting in a decrease in compressive strength, a deterioration in impact resistance performance, and a reduction in combustion performance; compared with Example 1, in Example 5, commercially available carbon nanotube II (FT6000) was used to replace commercially available carbon nanotube I (model FT9000) for the preparation of modified carbon nanotubes. Due to the excessive tube length of commercially available carbon nanotube II, the modification effect was not good, resulting in a decrease in compressive strength, a deterioration in impact resistance performance, and a reduction in combustion performance; compared with Example 1, in Example 6, commercially available basalt fibers (purchased from Jiangsu Tianlong) were used to replace the compound modified basalt fibers, resulting in a decrease in compressive strength, a deterioration in impact resistance performance, and a reduction in combustion performance; compared with Example 1, in Comparative Example 1, commercially available fly ash (purchased from Nanjing Yongjie) was used to replace the fly ash composite powder, resulting in a decrease in compressive strength, a deterioration in impact resistance performance, and a reduction in combustion performance; compared with Example 1, in Comparative Example 2, 20 parts of modified carbon nanotubes were not added in the components of step S2, resulting in a decrease in compressive strength, a deterioration in impact resistance performance, and a reduction in combustion performance; compared with Example 1, in Comparative Example 3, 16 parts of compound modified basalt fibers were not added in the components of step S2, resulting in a decrease in compressive strength, a deterioration in impact resistance performance, and a reduction in combustion performance.

Claims

1. A production method of a lightweight precast concrete wall panel, characterized in that, It includes the following steps: S1: By weight, add 180 - 220 parts of fly ash into 2800 - 3200 parts of deionized water and stir. Then add 6 - 8 parts of 0.4 - 0.6 mol / L antimony trichloride solution, 60 - 80 parts of 0.4 - 0.6 mol / L tin tetrachloride solution and 2 - 4 parts of sodium hydroxide for coating treatment to obtain fly ash composite powder. S2: Mix 160 - 200 parts of cement, 180 - 220 parts of fly ash composite powder, 16 - 20 parts of modified carbon nanotubes, 8 - 16 parts of compound modified basalt fiber, 3 - 5 parts of water reducing agent and 1.4 - 1.8 parts of hydroxypropyl methylcellulose. Then add 180 - 220 parts of ceramsite, 3.6 - 4.2 parts of α - olefin sulfonate and 350 - 360 parts of water and stir to obtain a slurry. Fix the steel bar welded mesh and polystyrene foam board, use the slurry to cast the wall panel, vibrate and compact it, and cure and form it to obtain a lightweight precast concrete wall panel.

2. The production method of a lightweight precast concrete wall panel according to claim 1, characterized in that, The conditions of the coating treatment include: adjust the pH to 4.2 - 4.6 for coating for 40 - 60 min, wash with water, filter, dry, and calcine.

3. The production method of a lightweight precast concrete wall panel according to claim 1, characterized in that, The preparation method of the modified carbon nanotubes includes: by weight, add 16 - 20 parts of carbon nanotubes and 4 - 6 parts of boron oxide into 90 - 100 parts of absolute ethanol and ultrasonically disperse them evenly, then calcine to obtain boron - containing carbon nanotubes; carboxylate the boron - containing carbon nanotubes to obtain modified carbon nanotubes.

4. The production method of a lightweight precast concrete wall panel according to claim 3, characterized in that, The tube length of the carbon nanotubes is 5 - 15 μm.

5. The production method of a lightweight precast concrete wall panel according to claim 3, characterized in that, The conditions of the carboxylation treatment include: first moisten 16 - 20 parts of boron - containing carbon nanotubes with absolute ethanol, then add 200 - 300 parts of sulfuric acid solution with a mass concentration of 10 - 20%, stir at 80 - 90 °C for 5 - 7 h, cool to room temperature, then add 20 - 30 parts of nitric acid and stir for 20 - 24 h, wash with water until the pH is neutral, and dry.

6. The production method of a lightweight precast concrete wallboard according to claim 1, characterized in that, The preparation method of the compound modified basalt fiber includes: by weight, first pretreat 8 - 16 parts of commercially available basalt fiber, and then add it into 160 - 200 parts of cetyltrimethylammonium bromide aqueous solution with a mass concentration of 0.6 - 0.8% for cationic modification to obtain cation - modified basalt fiber; couple - modify the cation - modified basalt fiber to obtain compound modified basalt fiber.

7. The production method of a lightweight precast concrete wall panel according to claim 6, characterized in that, The conditions of the pretreatment include: first place it in a muffle furnace for heat treatment at 480 - 500 °C for 50 - 60 min, cool, and then soak it in 0.8 - 1.2 mol / L hydrochloric acid solution for pickling at 70 - 80 °C for 4 - 6 h, and wash with deionized water until the pH is neutral.

8. The production method of a lightweight precast concrete wall panel according to claim 6, characterized in that, The conditions of the cationic modification include: impregnate at 60 - 70 °C for 6 - 8 h, filter, wash with water, and dry.

9. The production method of a lightweight precast concrete wall panel according to claim 6, characterized in that, The conditions of the couple - modification include: mix 80 - 90 parts of absolute ethanol and 10 - 20 parts of deionized water evenly, then add 0.6 - 0.8 parts of silane coupling agent KH602 and stir at 60 - 70 °C for 20 - 30 min, then add 8 - 16 parts of the cation - modified basalt fiber and soak for 6 - 8 h, filter, wash with absolute ethanol, and dry at 80 - 90 °C for 10 - 12 h.

10. A lightweight precast concrete wall panel, characterized in that, Prepared by the method according to any one of claims 1 to 9.

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