Bottom plate for anti-crack laminated slab and preparation method of bottom plate

Abstract

The invention discloses a bottom plate for an anti-crack laminated slab and a preparation method of the bottom plate, and belongs to the technical field of laminated slabs. The bottom plate for the anti-crack laminated slab is obtained by pouring and curing 4D steel fiber composite concrete slurry; the 4D steel fiber composite concrete slurry is prepared from the following raw material components in parts by mass: 20 to 35 parts of cement, 5 to 15 parts of mineral admixture, 25 to 40 parts of acrylate copolymer emulsion, 50 to 65 parts of sand, 0.05 to 0.2 part of defoaming agent, 0.1 to 0.25 part of polycarboxylic acid water reducing agent, 0.05 to 0.2 part of early strength agent and 0.4 to 0.9 part of modified 4D steel fiber, the acrylate copolymer emulsion is prepared from lauryl methacrylate, acrylamide, butyl perfluoroacrylate, 1H, 1H, 2H, 2H-perfluorodecyl acrylate, 1, 3-dimethylamino allyl phosphoric acid, 2-allylfuran, an initiator, a solvent and a solvent; aluminum palmitate is adopted as the defoaming agent; the modified 4D steel fiber is obtained by modifying maleimide siloxane.

Description

Technical Field

[0001] The present invention relates to a bottom plate for crack-resistant composite slabs and a preparation method thereof. Background Art

[0002] With the rapid development of prefabricated buildings in China, composite slabs, as core prefabricated components, have played an important role in improving construction efficiency, reducing construction costs, and enhancing the integrity of structures. However, their mechanical properties, especially the compressive strength and flexural strength of the bottom plate, directly affect the safety, durability, and service functions of building structures. Traditional bottom plates of composite slabs mostly adopt unidirectional prestressed concrete or ordinary reinforced concrete structures, but generally have problems such as low compressive strength and insufficient flexural strength, resulting in easy occurrence of penetrating cracks during construction hoisting and later use, affecting the integrity and durability of the structure.

[0003] To improve the mechanical properties, the applicant has tried to introduce 4D steel fibers to solve this problem. Summary of the Invention

[0004] The purpose of the present invention is to provide a bottom plate for crack-resistant composite slabs and a preparation method thereof to solve the technical problems mentioned in the above background art.

[0005] The technical solution to achieve the purpose of the present invention is as follows:

[0006] In the first aspect, the present invention provides a bottom plate for crack-resistant composite slabs. By mass fraction, the raw material components include 20 - 35 parts by mass of cement, 5 - 15 parts by mass of mineral admixture, 25 - 40 parts by mass of acrylate copolymer emulsion, 50 - 65 parts by mass of sand, 0.05 - 0.2 parts by mass of defoaming agent, 0.1 - 0.25 parts by mass of polycarboxylate water reducer, 0.05 - 0.2 parts by mass of early strength agent, and 0.4 - 0.9 parts by mass of modified 4D steel fibers.

[0007] Further, the acrylate copolymer emulsion is obtained by emulsion polymerization of lauryl methacrylate, acrylamide, perfluorobutyl acrylate, 1H,1H,2H,2H-perfluorodecyl acrylate, 1,3-dimethylaminoallyl phosphate, and 2-allylfuran.

[0008] Further, the defoaming agent adopts aluminum palmitate.

[0009] Further, the modified 4D steel fibers are obtained by hydrolysis and condensation wrapping of maleimidyl siloxane.

[0010] In the second aspect, the present invention provides a preparation method of the bottom plate for crack-resistant composite slabs as described in the first aspect, which is characterized by including the following preparation steps:

[0011] (1) Weigh and prepare the materials according to the corresponding mass parts of each raw material component;

[0012] (2) Dry and stir the cement, mineral admixture, sand, modified 4D steel fiber, and defoamer weighed in step (1) until evenly mixed to obtain dry materials;

[0013] (3) Add acrylate copolymer emulsion to the dry materials in step (2) and stir until a uniform paste is formed. Then add polycarboxylate superplasticizer and early strength agent, and continue to stir for 4 - 6 min to obtain a composite slurry;

[0014] (4) Pour the composite slurry in step (3) into a mold with a thickness of 10 - 20 mm, and perform natural curing for 24 hours, then perform wet curing at 20 °C and a humidity of ≥90% for 7 days to obtain the bottom plate for the crack - resistant composite slab.

[0015] Furthermore, the preparation steps of the acrylate copolymer emulsion are as follows: Mix lauryl methacrylate, acrylamide, perfluorobutyl acrylate, 1H,1H,2H,2H - perfluorodecyl acrylate, 1,3 - dimethylaminoallyl phosphate, 2 - allylfuran, emulsifier, and pure water and stir until fully emulsified and dissolved. Adjust the pH to 7, introduce nitrogen to remove air, heat to 43 - 47 °C, add 4.2 - 4.4 mass parts of initiator ammonium persulfate and react at a constant temperature for 7.5 - 8.5 h to obtain the acrylate copolymer emulsion.

[0016] Furthermore, the mass ratio of lauryl methacrylate, acrylamide, perfluorobutyl acrylate, 1H,1H,2H,2H - perfluorodecyl acrylate, 1,3 - dimethylaminoallyl phosphate, 2 - allylfuran, emulsifier, and pure water is (0.04 - 0.06):10:(0.01 - 0.03):(0.02 - 0.04):(0.8 - 1.2):(2 - 4):4:40.

[0017] Furthermore, the preparation method of the modified 4D steel fiber is as follows: Mix maleimidyl siloxane, absolute ethanol, and water with a mass ratio of 15:20 - 30:70 - 80 until evenly mixed, adjust the pH to 4 - 6 with 1 mol / L oxalic acid aqueous solution, stir at 10 - 30 °C and 300 - 500 r / min for 2.5 - 3.5 h, then add 10% NaOH solution to adjust the pH to 7 to prepare a silane hydrolysis solution; Immerse the 4D steel fiber in a 10% NaOH solution with a mass 15 - 25 times its own mass for 9 - 11 min, take it out and dry it, then immerse it in the silane hydrolysis solution for 18 - 22 min, take it out and dry it to obtain the modified 4D steel fiber.

[0018] Further, the preparation steps of the maleimide group siloxane are as follows: Mix N-(4-hydroxyphenyl) maleamide, benzene, and triethylamine, and stir the mixture at 68-72°C for 50-70 minutes. Subsequently, dropwise add a triethoxysilane chloride mixture at a rate of 1-3 drops per second. After the addition is complete, continue to stir and react at 68-72°C for 7-8 hours. Filter, wash with water, and rotary evaporate to remove benzene to obtain the maleimide group siloxane.

[0019] Further, the molar ratio of N-(4-hydroxyphenyl) maleamide, triethylamine, and triethoxysilane chloride is 1.8-1.9:1:1; the mass ratio of N-(4-hydroxyphenyl) maleamide to benzene is 1:8-12; the triethoxysilane chloride mixture is obtained by mixing triethoxysilane chloride and benzene at a mass ratio of 1:8.5-9.5 and stirring for 18-20 minutes.

[0020] Adopting the above technical solutions, the present invention has the following beneficial effects:

[0021] (1) By introducing 4D steel fibers with a unique end hook structure design into the bottom plate for crack-resistant composite slabs, the present invention effectively increases the tensile strength of the crack-resistant composite slabs and prevents the bottom plate for crack-resistant composite slabs from cracking through the anchoring effect.

[0022] (2) By hydrolytic condensation of maleimide group siloxane to wrap 4D steel fibers, the present invention can effectively improve the agglomeration problem of 4D steel fibers in the concrete matrix, ensuring the effect of 4D steel fibers in enhancing the tensile strength and flexural strength of the bottom plate for crack-resistant composite slabs.

[0023] (3) The present invention also introduces an acrylate copolymer emulsion, which is obtained by copolymerizing lauryl methacrylate, acrylamide, perfluorobutyl acrylate, 1H,1H,2H,2H-perfluorodecyl acrylate, 1,3-dimethylaminoallyl phosphate, and 2-allylfuran by emulsion polymerization method. It forms a three-dimensional network structure in the cement paste and wraps the surface of the aggregate, enhancing the bonding strength between the cement paste and the aggregate, and can effectively increase the toughness of the bottom plate for crack-resistant composite slabs and reduce crack propagation.

[0024] (4) The defoaming agent of the present invention is aluminum palmitate. When cement, mineral admixture, acrylate copolymer emulsion, sand, defoaming agent, polycarboxylate water reducer, early strength agent, and modified 4D steel fibers are mixed into a slurry, aluminum palmitate reacts with phosphoric acid in the acrylate copolymer emulsion to form insoluble aluminum phosphate, which can effectively improve the compactness and hardness of the bottom plate for crack-resistant composite slabs and increase the impermeability of the bottom plate for crack-resistant composite slabs.

[0025] (5) After mixing cement, mineral admixture, acrylate copolymer emulsion, sand, defoamer, polycarboxylate water reducer, early strength agent, and modified 4D steel fiber into a slurry, the acrylate copolymer forms a three-dimensional network structure in the cement paste. The furan groups on the acrylate copolymer react with the maleimide on the modified 4D steel fiber through a D-A reaction, effectively increasing the interfacial bonding ability between the 4D steel fiber and the base material of the bottom plate for crack-resistant laminated plates. This effectively avoids the problem of weakening the tensile strength and flexural strength of the bottom plate for 4D steel fiber-reinforced crack-resistant laminated plates caused by insufficient bonding force between the 4D steel fiber and the base material of the bottom plate for crack-resistant laminated plates, and further enhances the compressive strength and flexural strength of the bottom plate for crack-resistant laminated plates. Detailed implementation mode

[0026] In order to better understand the above technical solutions, the following will describe the above technical solutions in detail in combination with specific implementation modes.

[0027] Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0028] The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and cannot be used to limit the protection scope of the present invention.

[0029] The raw materials of the embodiments and comparative examples of the present invention are as follows:

[0030] The cement is Conch brand P·Ⅱ 52.5 cement, with an initial setting time of 137 min, a final setting time of 192 min, 3d and 28d flexural strengths of 6.2 MPa and 8.5 MPa respectively, 3d and 28d compressive strengths of 34.4 MPa and 58.7 MPa respectively, and a specific surface area of 358 m 2 / kg.

[0031] Mineral admixture: S105 grade mineral powder, with a 28d activity index of 108% and a fluidity ratio of 110%.

[0032] Sand: The diameter specifications of quartz sand are 0.83 - 1.65 mm, 0.41 - 0.83 mm, and 0.21 - 0.41 mm.

[0033] Polycarboxylate water reducer: Subote PCA-HW type polycarboxylate water reducer, with a water reduction rate > 40%.

[0034] 4D steel fiber: length 60 mm, diameter 0.75 mm.

[0035] Early strength agent: Calcium formate.

[0036] The preparation method of 1,3-dimethylaminoallyl phosphoric acid is as follows: Mix dimethylamine and phosphorous acid in a molar ratio of 1:1, and dropwise add 1 M dilute hydrochloric acid at a rate of 1 drop per second until the pH value reaches 1. After the addition is complete, heat from room temperature to 85 °C at a rate of 5 °C per minute, and dropwise add acrolein in an amount equimolar to dimethylamine at a rate of 1 drop per second. After the addition is complete, continue the heat preservation reaction for 2 hours.

[0037] (Example 1)

[0038] A preparation method of a bottom plate for a crack-resistant laminated slab, characterized by comprising the following preparation steps:

[0039] (1) Weigh and prepare materials according to the following mass parts corresponding to each raw material component: 20 parts by mass of cement, 5 parts by mass of mineral admixture, 25 parts by mass of acrylate copolymer emulsion, 50 parts by mass of sand, 0.05 part by mass of defoamer, 0.1 part by mass of polycarboxylate water reducer, 0.05 part by mass of early strength agent, 0.4 part by mass of modified 4D steel fiber;

[0040] (2) Dry the cement, mineral admixture, sand, modified 4D steel fiber, and defoamer weighed in step (1) and stir and mix them evenly at 1000 rpm for 10 minutes to obtain dry materials;

[0041] (3) Add the acrylate copolymer emulsion to the dry materials in step (2) and stir at 1500 rpm until a uniform slurry is formed. Then add the polycarboxylate water reducer and early strength agent, and stir at 80 rpm for 4 minutes to obtain a composite slurry;

[0042] (4) Pour the composite slurry in step (3) into a mold with a thickness of 10 mm, and after natural curing for 24 hours, carry out wet curing at 20 °C and a humidity of ≥90% for 7 days to obtain the bottom plate for the crack-resistant laminated slab.

[0043] The preparation steps of the acrylate copolymer emulsion are as follows: Mix lauryl methacrylate, acrylamide, perfluorobutyl acrylate, 1H,1H,2H,2H-perfluorodecyl acrylate, 1,3-dimethylaminoallyl phosphoric acid, 2-allylfuran, emulsifier, and pure water, stir until fully emulsified and dissolved, adjust the pH to 7, introduce nitrogen to remove air, heat to 43 °C, add 4.2 parts by mass of initiator ammonium persulfate, and carry out a constant temperature reaction for 7.5 hours to obtain the acrylate copolymer emulsion.

[0044] The mass ratio of lauryl methacrylate, acrylamide, perfluorobutyl acrylate, 1H,1H,2H,2H-perfluorodecyl acrylate, 1,3-dimethylaminoallyl phosphoric acid, 2-allylfuran, emulsifier, and pure water is (0.04):10:0.01:0.02:0.8:2:4:40.

[0045] The preparation method of the modified 4D steel fiber is as follows: Mix maleimide-based siloxane, absolute ethanol, and water in a mass ratio of 15:20:80 evenly, adjust the pH to 4 with 1 mol / L oxalic acid aqueous solution, stir at 10°C and 300 r / min for 2.5 h, then add 10% NaOH solution to adjust the pH to 7 to prepare a silane hydrolysis solution; Immerse the 4D steel fiber in 10% NaOH solution with a mass 15 times its own mass for 9 min, take it out, dry it, and then immerse it in the silane hydrolysis solution for 18 min, take it out and dry it to obtain the modified 4D steel fiber.

[0046] The preparation steps of the maleimide-based siloxane are as follows: Mix N-(4-hydroxyphenyl) maleamide, benzene, and triethylamine and stir at 68°C for 50 min, then dropwise add triethoxysilane chloride mixture at a rate of 1 drop / s. After the dropping is completed, continue to stir and react at 68°C for 7 h, filter, wash with water, and remove benzene by rotary evaporation to obtain maleimide-based siloxane.

[0047] The molar ratio of N-(4-hydroxyphenyl) maleamide, triethylamine, and triethoxysilane chloride is 1.8:1:1; the mass ratio of N-(4-hydroxyphenyl) maleamide to benzene is 1:8; the triethoxysilane chloride mixture is obtained by mixing triethoxysilane chloride and benzene in a mass ratio of 1:8.5 and stirring for 18 min.

[0048] (Example 2)

[0049] A preparation method of a bottom plate for a crack-resistant laminated plate, characterized by comprising the following preparation steps:

[0050] (1) Weigh and prepare materials according to the following mass parts of each raw material component: 30 parts by mass of cement, 10 parts by mass of mineral admixture, 35 parts by mass of acrylate copolymer emulsion, 58 parts by mass of sand, 0.15 part by mass of defoamer, 0.18 part by mass of polycarboxylate water reducer, 0.13 part by mass of early strength agent, 0.7 part by mass of modified 4D steel fiber;

[0051] (2) Dry the cement, mineral admixture, sand, modified 4D steel fiber, and defoamer weighed in step (1) and stir and mix evenly at 1000 rpm for 10 min to obtain dry materials;

[0052] (3) Add acrylate copolymer emulsion to the dry materials in step (2) and stir at 1500 rpm until a uniform slurry is formed, then add polycarboxylate water reducer and early strength agent, and stir at 80 rpm for 5 min to obtain a composite slurry;

[0053] (4) Pour the composite slurry in step (3) into a mold with a thickness of 15 mm, cure naturally for 24 hours, and then cure under wet conditions at 20°C and a humidity of ≥90% for 7 days to obtain a bottom plate for a crack-resistant laminated plate.

[0054] The preparation steps of the acrylate copolymer emulsion are as follows: Mix lauryl methacrylate, acrylamide, butyl perfluoracrylate, 1H,1H,2H,2H-perfluorodecyl acrylate, 1,3-dimethylaminoallyl phosphate, 2-allylfuran, emulsifier, and pure water and stir until fully emulsified and dissolved. Adjust the pH to 7, introduce nitrogen to remove air, heat to 45 °C, add 4.3 parts by mass of ammonium persulfate initiator and react at a constant temperature for 8 h to obtain the acrylate copolymer emulsion.

[0055] The mass ratio of lauryl methacrylate, acrylamide, butyl perfluoracrylate, 1H,1H,2H,2H-perfluorodecyl acrylate, 1,3-dimethylaminoallyl phosphate, 2-allylfuran, emulsifier, and pure water is 0.05:10:0.02:0.03:1:3:4:40.

[0056] The preparation method of the modified 4D steel fiber is as follows: Mix maleimidyl siloxane, absolute ethanol, and water in a mass ratio of 15:25:75 and mix evenly. Adjust the pH to 5 with 1 mol / L oxalic acid aqueous solution, stir at 20 °C and 400 r / min for 3 h, then add 10% NaOH solution to adjust the pH to 7 to prepare a silane hydrolysis solution; Immerse the 4D steel fiber in 10% NaOH solution with a mass 20 times its own for 10 min, take it out, dry it, and then immerse it in the silane hydrolysis solution for 20 min, take it out and dry it to obtain the modified 4D steel fiber.

[0057] The preparation steps of maleimidyl siloxane are as follows: Mix N-(4-hydroxyphenyl) maleimide, benzene, and triethylamine and stir at 70 °C for 60 min, then dropwise add a triethoxysilane chloride mixture at a rate of 2 drops / s. After the addition is complete, continue to stir and react at 70 °C for 7.5 h, filter, wash with water, and rotary evaporate to remove benzene to obtain maleimidyl siloxane.

[0058] The molar ratio of N-(4-hydroxyphenyl) maleimide, triethylamine, and triethoxysilane chloride is 1.85:1:1; The mass ratio of N-(4-hydroxyphenyl) maleimide to benzene is 1:10; The triethoxysilane chloride mixture is obtained by mixing triethoxysilane chloride and benzene in a mass ratio of 1:9 and stirring for 19 min.

[0059] (Example 3)

[0060] A preparation method of a bottom plate for a crack-resistant laminated plate, characterized by comprising the following preparation steps:

[0061] (1) Weigh and prepare the materials according to the following mass parts corresponding to each raw material component: 35 parts by mass of cement, 15 parts by mass of mineral admixture, 40 parts by mass of acrylate copolymer emulsion, 65 parts by mass of sand, 0.2 parts by mass of defoamer, 0.25 parts by mass of polycarboxylate water reducer, 0.2 parts by mass of early strength agent, and 0.9 parts by mass of modified 4D steel fiber;

[0062] (2) Dry the cement, mineral admixture, sand, modified 4D steel fiber, and defoamer weighed in step (1) and stir and mix them evenly at 1000 rpm for 10 min to obtain dry materials;

[0063] (3) Add the acrylate copolymer emulsion to the dry materials in step (2) and stir at 1500 rpm until a uniform slurry is formed. Then add the polycarboxylate water reducer and early strength agent and stir at 80 rpm for 6 min to obtain a composite slurry;

[0064] (4) Pour the composite slurry in step (3) into a mold with a thickness of 20 mm, cure it naturally for 24 hours, and then cure it under wet conditions at 20 °C and a humidity of ≥90% for 7 days to obtain the bottom plate for the crack-resistant composite slab.

[0065] The preparation steps of the acrylate copolymer emulsion are as follows: Mix lauryl methacrylate, acrylamide, butyl perfluoracrylate, 1H,1H,2H,2H-perfluorodecyl acrylate, 1,3-dimethylaminoallyl phosphate, 2-allylfuran, emulsifier, and pure water and stir until fully emulsified and dissolved. Adjust the pH to 7, pass in nitrogen to remove air, heat to 47 °C, add 4.4 parts by mass of initiator ammonium persulfate, and react at a constant temperature for 8.5 h to obtain the acrylate copolymer emulsion.

[0066] The mass ratio of lauryl methacrylate, acrylamide, butyl perfluoracrylate, 1H,1H,2H,2H-perfluorodecyl acrylate, 1,3-dimethylaminoallyl phosphate, 2-allylfuran, emulsifier, and pure water is 0.06:10:0.03:0.04:1.2:4:4:40.

[0067] The preparation method of the modified 4D steel fiber is as follows: Mix maleimidyl siloxane, absolute ethanol, and water in a mass ratio of 15:30:70 and mix them evenly. Adjust the pH to 6 with 1 mol / L oxalic acid aqueous solution, stir at 30 °C and 500 r / min for 3.5 h, then add 10% NaOH solution to adjust the pH to 7 to prepare a silane hydrolysis solution; Immerse the 4D steel fiber in a 10% NaOH solution with a mass 25 times its own mass for 11 min, fish it out and dry it, then immerse it in the silane hydrolysis solution for 22 min, fish it out and dry it to obtain the modified 4D steel fiber.

[0068] The preparation steps of the maleimide group-containing siloxane are as follows: Mix N-(4-hydroxyphenyl) maleamide, benzene, and triethylamine, and stir the mixture at 72 °C for 70 min. Then, dropwise add a triethoxysilane chloride mixture at a rate of 3 drops / s. After the addition is complete, continue to stir and react at 72 °C for 8 h. Filter, wash with water, and rotary evaporate to remove benzene to obtain the maleimide group-containing siloxane.

[0069] The molar ratio of the N-(4-hydroxyphenyl) maleamide, triethylamine, and triethoxysilane chloride is 1.9:1:1; the mass ratio of the N-(4-hydroxyphenyl) maleamide to benzene is 1:12; the triethoxysilane chloride mixture is obtained by mixing triethoxysilane chloride and benzene at a mass ratio of 1:9.5 and stirring for 20 min.

[0070] (Comparative Example 1)

[0071] The difference between Comparative Example 1 and Example 2 is that the raw material components of the bottom plate for the crack-resistant laminated plate include 30 parts by mass of cement, 10 parts by mass of mineral admixture, 35 parts by mass of acrylate copolymer emulsion, 58 parts by mass of sand, 0.15 part by mass of defoaming agent, 0.18 part by mass of polycarboxylate water reducer, 0.13 part by mass of early strength agent, and 0.7 part by mass of 4D steel fiber. The remaining components and steps are the same as those in Example 2.

[0072] (Comparative Example 2)

[0073] The difference between Comparative Example 2 and Example 2 is that the raw material components of the bottom plate for the crack-resistant laminated plate include only 30 parts by mass of cement, 10 parts by mass of mineral admixture, 0.75 part by mass of water, 58 parts by mass of sand, 0.15 part by mass of defoaming agent, 0.18 part by mass of polycarboxylate water reducer, 0.13 part by mass of early strength agent, and 0.7 part by mass of modified 4D steel fiber. The remaining components and steps are the same as those in Example 2.

[0074] (Comparative Example 3)

[0075] The difference between Comparative Example 3 and Example 2 is that an organosilicon defoaming agent is used as the defoaming agent, and the remaining components and steps are the same as those in Example 2.

[0076] The following Table 1 shows the results of various performance data of the bottom plates for crack-resistant laminated plates prepared in the examples and comparative examples tested according to the standard JC / T 984-2011:

[0077] Table 1

[0078] 7d impermeability pressure (MPa) 28d compressive strength (MPa) 28d flexural strength (MPa) Example 1 1.8 105.9 16.7 Example 2 2.0 106.4 17.3 Example 3 1.9 106.1 16.9 Comparative Example 1 1.8 63.58 9.04 Comparative Example 2 0.5 82.53 11.8 Comparative Example 3 0.9 102.8 15.1

[0079] As can be seen from Table 1 above, the bottom plates for crack-resistant laminated plates prepared in Examples 1 to 3 have good flexural strength, compressive strength, and waterproof and impermeable properties.

[0080] The difference between Comparative Example 1 and Example 2 is that the bottom plate for the crack-resistant laminated slab is modified with 4D steel fibers, and steel fiber agglomeration appears in the bottom plate, with poor flexural strength and compressive strength.

[0081] The difference between Comparative Example 2 and Example 2 is that the polymer emulsion is not added to the bottom plate for the crack-resistant laminated slab, and the flexural strength and compressive strength of the prepared bottom plate for the crack-resistant laminated slab are poorer than those of Example 2, and the waterproof and impermeability properties are also poorer than those of Example 2.

[0082] The difference between Comparative Example 3 and Example 2 is that aluminum palmitate is not used as an antifoaming agent for the bottom plate of the crack-resistant laminated slab, and the flexural strength and compressive strength of the prepared bottom plate for the crack-resistant laminated slab are poorer than those of Example 2, and the waterproof and impermeability properties are also poorer than those of Example 2.

[0083] The specific embodiments described above further elaborate on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A bottom plate for a crack-resistant laminated slab, characterized in that, Calculated by mass, the raw material components include 20 to 35 parts by mass of cement, 5 to 15 parts by mass of mineral admixture, 25 to 40 parts by mass of acrylic copolymer emulsion, 50 to 65 parts by mass of sand, 0.05 to 0.2 parts by mass of defoaming agent, 0.1 to 0.25 parts by mass of polycarboxylic acid water reducer, 0.05 to 0.2 parts by mass of early strength agent, and 0.4 to 0.9 parts by mass of modified 4D steel fiber.

2. The bottom plate for crack-resistant composite panels according to claim 1, characterized in that: The acrylate copolymer emulsion is obtained by copolymerizing lauryl methacrylate, acrylamide, perfluorobutyl acrylate, 1H,1H,2H,2H-perfluorodecyl acrylate, 1,3-dimethylamino allyl phosphoric acid and 2-allyl furan through an emulsion polymerization method.

3. The bottom plate for crack-resistant laminated slab according to claim 1, characterized in that, The defoaming agent is aluminum palmitate.

4. The bottom plate for crack-resistant composite slab according to claim 1, wherein The modified 4D steel fiber is obtained by hydrolysis, condensation and wrapping of maleimide-based siloxane.

5. A preparation method of a bottom plate for a crack-resistant laminated slab according to any one of claims 1 to 4, characterized in that, The method comprises the following preparation steps: (1) Weigh and prepare the raw materials according to the corresponding mass fractions of each raw material component: (2) drying and stirring the cement, mineral admixture, sand, modified 4D steel fiber, and defoamer weighed in step (1) to obtain a dry material; (3) adding the acrylic copolymer emulsion to the dry material of step (2) in sequence and stirring until a uniform slurry is formed, then adding the polycarboxylic acid water reducer and the early strength agent, and continuing to stir for 4 to 6 minutes to obtain a composite slurry; (4) The composite slurry of step (3) is poured into a mold with a thickness of 10 to 20 mm, and after natural curing for 24 hours, it is wet-cured at 20° C. and humidity ≥ 90% for 7 days to obtain a base plate for a crack-resistant composite board.

6. The preparation method of the bottom plate for the crack-resistant laminated slab according to claim 5, characterized in that, The preparation steps of the acrylate copolymer emulsion are as follows: lauryl methacrylate, acrylamide, perfluorobutyl acrylate, 1H,1H,2H,2H-perfluorodecyl acrylate, 1,3-dimethylaminoallyl phosphoric acid, 2-allylfuran, an emulsifier, and pure water are mixed and stirred until fully emulsified and dissolved, the pH is adjusted to 7, nitrogen is introduced to exclude air, the mixture is heated to 43-47° C., 4.2-4.4 parts by mass of ammonium persulfate as an initiator is added, and the mixture is reacted at a constant temperature for 7.5-8.5 hours to obtain the acrylate copolymer emulsion.

7. The preparation method of the bottom plate for the crack-resistant laminated slab according to claim 6, characterized in that, The mass ratio of lauryl methacrylate, acrylamide, perfluorobutyl acrylate, 1H,1H,2H,2H-perfluorodecyl acrylate, 1,3-dimethylamino allyl phosphoric acid, 2-allylfuran, emulsifier and pure water is (0.04-0.06):10:(0.01-0.03):(0.02-0.04):(0.8-1.2):(2-4):4:

40.

8. The preparation method of the bottom plate for the crack-resistant laminated slab according to claim 5, characterized in that, The preparation method of the modified 4D steel fiber is as follows: Mix maleimide group siloxane, absolute ethanol, and water in a mass ratio of 15:20-30:70-80 evenly, adjust the pH to 4-6 with 1 mol / L oxalic acid aqueous solution, stir at 10-30 °C and 300-500 r / min for 2.5-3.5 h, then add 10% NaOH solution to adjust the pH to 7 to prepare a silane hydrolysis solution; Immerse the 4D steel fiber in 10% NaOH solution with a mass 15-25 times its own mass for 9-11 min, fish it out and dry it, then immerse it in the silane hydrolysis solution for 18-22 min, fish it out and dry it to obtain the modified 4D steel fiber.

9. The preparation method of the bottom plate for the crack-resistant laminated slab according to claim 8, characterized in that, The preparation steps of the maleimide group siloxane are as follows: Mix N-(4-hydroxyphenyl) maleamide, benzene, and triethylamine, stir and mix at 68-72 °C for 50-70 min, then dropwise add triethoxysilane chloride mixture at a rate of 1-3 drops / s. After the dropping is completed, continue to stir and react at 68-72 °C for 7-8 h, filter, wash with water, and rotary evaporate to remove benzene to obtain maleimide group siloxane.

10. The preparation method of the bottom plate for the crack-resistant laminated slab according to claim 9, characterized in that, The molar ratio of N-(4-hydroxyphenyl) maleamide, triethylamine, and triethoxysilane chloride is 1.8-1.9:1:1; the mass ratio of N-(4-hydroxyphenyl) maleamide to benzene is 1:8-12; the triethoxysilane chloride mixture is obtained by mixing triethoxysilane chloride and benzene in a mass ratio of 1:8.5-9.5 and stirring for 18-20 min.