High ductility cement-based material, method for its production and raised floor

Abstract

The application discloses a kind of high ductility cement-based material and preparation method and overhead floor, belong to building material technical field, its technical scheme main point is the cement-based material includes following weight parts of raw material: cement 100-400 parts, active brick micro powder 100-600 parts, fine aggregate 100-1000 parts, water 300-500 parts, water reducing agent 2-5 parts, reinforcing agent 1-3 parts, re-dispersible latex powder 1-5 parts, heat-resistant filler 1-10 parts, fiber 5-15 parts;The active brick micro powder is obtained by following preparation method: waste brick is crushed and sieved to obtain waste brick particles with particle size less than 5mm, 100-600 weight parts of waste brick particles are baked at a temperature of 105 DEG C for 30-60 minutes, and then cooled for 30-40 minutes, then the waste brick particles are ground with 0.5-1.5 weight parts of aluminum-based activator at a speed of 30-50 revolutions per minute for 20-40 minutes, and then sieved to obtain active brick micro powder, which overcomes the brittle cracking of ECC material at high temperature.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, and in particular to a high-ductility cement-based material, its preparation method, and a raised floor. Background Technology

[0002] Traditional concrete is a brittle material, resistant to compression but not tension, with a very small tensile elongation of less than one-thousandth. Therefore, when the deformation of traditional cement-based materials is constrained by factors such as temperature and shrinkage, cracks easily form. To overcome the brittleness of concrete, engineered cementitious composites (ECCs) have been successfully applied. The main difference between ECCs and traditional constrained reinforced cement-based materials is that ECCs form numerous microcracks during tension without reducing their load-bearing capacity. The formation of multiple microcracks can potentially increase the macroscopic tensile strain of the material by nearly a hundredfold. Due to the bridging effect of the fibers between cracks, the overall load-bearing capacity of ECCs is not significantly weakened by the formation of microcracks. However, in order to achieve strain hardening and multi-point cracking properties, ECC materials require a reduction in sand content compared to ordinary mortar, and coarse aggregates cannot be used. This leads to increased drying shrinkage of ECC materials during the setting and hardening process. Especially under high-temperature environments, ECC materials are more prone to brittle cracking, i.e., large crack widths. Although ECC materials have the characteristics of multi-point cracking and small crack widths, these cracks still have a significant impact on the long-term durability of the structure compared to materials that do not experience brittle cracking. Summary of the Invention

[0003] To overcome the problem that ECC materials are more prone to brittle cracking at high temperatures, this invention provides a high-ductility cement-based material, its preparation method, and a raised floor.

[0004] The first aspect of this invention is to provide a high-ductility cement-based material, specifically employing the following technical solution: A high-ductility cement-based material, comprising the following raw materials in parts by weight: 100-400 parts cement, 100-600 parts activated brick powder, 100-1000 parts fine aggregate, 300-500 parts water, 2-5 parts water-reducing agent, 1-3 parts reinforcing agent, 1-5 parts redispersible latex powder, 1-10 parts heat-resistant filler, and 5-15 parts fiber; The activated brick powder is obtained by the following preparation method: waste bricks are crushed and screened to obtain waste brick particles with a particle size of less than 5 mm. 100-600 parts by weight of waste brick particles are dried at a temperature of 105℃ for 30-60 min, then cooled for 30-40 min. The waste brick particles are then ground with 0.5-1.5 parts by weight of aluminum-based activator at a speed of 30-50 rpm for 20-40 min and then screened to obtain activated brick powder.

[0005] By adopting the above technical solution, this application can destroy the surface state of the glassy minerals in the waste brick particles after grinding with aluminum-based activators, reduce the degree of polymerization of the mineral structure, increase the reaction contact area between the waste brick particles and the aluminum-based activators, and enable the waste brick particles and aluminum-based activators to better fuse. This can more quickly weaken the Si-O and Al-O bond energies in the waste brick particles, reduce the degree of polymerization of the waste brick particles, and make silicon ions and aluminum ions in an active state, thereby increasing the activity of the waste brick particles by more than 80%, so that they can effectively participate in the hydration reaction of cement. The reason for selecting aluminum-based activators in this application is that aluminum ions in aluminum-based salts can participate in the chemical reaction and solubilize the cement during hydration, further dissolving the less active waste brick particles, thus making the cement hydration reaction more thorough. Furthermore, the combined use of activated brick powder with reinforcing agents, redispersible latex powder, and heat-resistant fillers results in cement-based materials with high density and low drying shrinkage. After boiling in 100°C water for 4 hours, the tensile elongation of the cement-based material is above 4.0%, and the equivalent flexural toughness is above 300 KJ / m. 3 The above conditions apply, and the average crack width of cement-based materials is 45-80 μm, with an average number of cracks of 15-30.

[0006] Preferably, the activated brick powder is obtained by the following preparation method: 100-600 parts by weight of waste brick particles are dried at 105°C for 30-60 minutes, then cooled for 30-40 minutes. The waste brick particles are then ground with 0.25-0.75 parts by weight of aluminum-based activator at a speed of 30-50 rpm for 20-40 minutes and sieved to obtain modified brick powder. The modified brick powder is then mixed with 100-600 parts by weight of slag powder and 0.25-0.75 parts by weight of aluminum-based activator at a speed of 3-15 rpm for 10-20 minutes to obtain activated brick powder.

[0007] By adopting the above technical solution, the aluminum-based activator can be added in two stages, which can make the waste brick particles and slag more uniformly mixed, and the activity of the waste brick particles can be increased by more than 85%, effectively promoting the cement hydration reaction and improving the brittle crack resistance of cement-based materials.

[0008] Preferably, the particle size of the activated brick powder is less than 100 μm, wherein the cumulative sieve residue percentage of activated brick powder with a particle size of less than 10 μm is 30-50%, and the cumulative sieve residue percentage of activated brick powder with a particle size of less than 50 μm is 70-90%.

[0009] Preferably, the aluminum-based activator is one of aluminum phosphate, aluminum sulfate, potassium aluminum sulfate, aluminum nitrate, and aluminum chloride.

[0010] Preferably, the reinforcing agent is one of sodium silicate, potassium silicate, and calcium silicate.

[0011] Preferably, the heat-resistant filler is aluminum silicate.

[0012] Preferably, the fiber has a length of 10-13 mm and a diameter of 0.04-0.14 mm.

[0013] Preferably, the fine aggregate has a particle size of 40-80 mesh.

[0014] A second aspect of this application is to provide a method for preparing a highly ductile cement-based material, comprising the following preparation steps: (1) Mix cement and active brick powder at a speed of 3-15 rpm for 10-20 minutes to obtain dry mixed powder for later use; (2) Add water-reducing agent, reinforcing agent and redispersible latex powder to water and stir evenly to obtain a mixed suspension for later use; (3) Stir the dry powder obtained in step (1) and fine aggregate at 58-65 rpm for 40 seconds, then add heat-resistant filler and continue stirring for 60 seconds, then add the mixed suspension obtained in step (2) and stir at 62-67 rpm for 2-3 minutes, then stir at 115-135 rpm for 1-2 minutes to obtain a uniformly flowing premix. (4) Add fiber to the premix obtained in step (3) and stir for 3-4 minutes at 57-63 rpm to obtain a high ductility cement-based material.

[0015] A third aspect of this application is to provide a raised floor, comprising a surface layer and a structural layer, wherein the surface layer is cast using the aforementioned premixed material and has a thickness of 1-3 mm; and the structural layer is cast using the aforementioned high-ductility cement-based material in multiple layers, each layer having a thickness of no more than 15 mm and a casting interval of no more than 15 minutes between each layer.

[0016] In summary, the present invention has the following beneficial effects: After modifying the waste brick particles, this application not only improves the utilization rate of waste bricks, but also the active brick powder obtained after the waste brick particles are treated with aluminum-based activators, combined with reinforcing agents, heat-resistant fillers, and redispersible latex powder, can effectively promote the hydration reaction of cement, so that the resulting cement-based material has good water-boiling resistance, and still has strain hardening characteristics and crack-cracking characteristics after high-temperature treatment at 100℃. However, the average crack width and average number of cracks in the cement-based material are significantly reduced, and brittle fracture will not occur, resulting in good crack resistance. Detailed Implementation

[0017] The present invention will be further described in detail below with reference to the embodiments.

[0018] All raw materials used in this application are commercially available, including: The water-reducing agent used is a high-performance polycarboxylate water-reducing agent; The aluminum-based activator is one of aluminum phosphate, aluminum sulfate, potassium aluminum sulfate, aluminum nitrate, and aluminum chloride; Fine aggregate is one of the following: quartz, basalt, or granite with a particle size of 40-80 mesh. The reinforcing agent is one of sodium silicate, potassium silicate, and calcium silicate; The heat-resistant filler is aluminum silicate; The redispersible latex powder is one of ethylene-vinyl acetate copolymer and acrylic copolymer. In the examples and comparative examples of this application, ethylene-vinyl acetate copolymer is used. The fiber is a modified polypropylene fiber, 10-13mm in length and 0.04-0.14mm in diameter, purchased from Ningbo Shike New Materials.

[0019] Preparation Example Preparation Example 1 The preparation method of activated brick powder includes the following steps: Waste bricks generated during building demolition are crushed and sieved to obtain waste brick particles with a particle size of less than 5 mm. 100 kg of waste brick particles are dried at 105℃ for 30 min, then cooled for 300 min. The waste brick particles are then ground with 0.5 kg of aluminum sulfate at a speed of 30 rpm for 20 min, followed by sieving to obtain activated brick powder with a specific surface area of ​​300 m². 2 / kg, with a particle size of less than 100μm, wherein the cumulative sieve residue percentage of active brick powder with a particle size of less than 10μm is 30%, and the cumulative sieve residue percentage of active brick powder with a particle size of less than 50μm is 70%, and the activity of the prepared active brick powder is 80.5%.

[0020] Preparation Example 2 The preparation method of activated brick powder includes the following steps: Waste bricks generated during building demolition are crushed and sieved to obtain waste brick particles with a particle size of less than 5 mm. 300 kg of waste brick particles are dried at 105℃ for 50 min, then cooled for 30 min. The waste brick particles are then ground with 1.0 kg of aluminum phosphate at a speed of 40 rpm for 30 min, followed by sieving to obtain activated brick powder. The specific surface area of ​​the activated brick powder is 420 m². 2 / kg, with a particle size of less than 100μm, of which the cumulative sieve residue percentage of active brick powder with a particle size of less than 10μm is 38%, and the cumulative sieve residue percentage of active brick powder with a particle size of less than 50μm is 79%, and the activity of the prepared active brick powder is 82%.

[0021] Preparation Example 3 The preparation method of activated brick powder includes the following steps: Waste bricks generated during building demolition are crushed and sieved to obtain waste brick particles with a particle size of less than 5 mm. 600 kg of waste brick particles are dried at 105℃ for 60 min, then cooled for 40 min. The waste brick particles are then ground with 1.5 kg of potassium aluminum sulfate at 50 rpm for 40 min, followed by sieving to obtain activated brick powder with a specific surface area of ​​500 m². 2 / kg, with a particle size of less than 100μm, wherein the cumulative sieve residue percentage of active brick powder with a particle size of less than 10μm is 50%, and the cumulative sieve residue percentage of active brick powder with a particle size of less than 50μm is 90%, and the activity of the prepared active brick powder is 83%.

[0022] Preparation Example 4 The preparation method of activated brick powder includes the following steps: Waste bricks generated during building demolition are crushed and sieved to obtain waste brick particles with a particle size less than 5 mm. 100 kg of waste brick particles are dried at 105℃ for 60 min, then cooled for 40 min. The waste brick particles are then ground with 0.25 kg of aluminum nitrate at a speed of 50 rpm for 40 min, followed by sieving to obtain modified brick powder. The modified brick powder is then mixed with 100 kg of slag powder and 0.25 kg of aluminum nitrate at a speed of 3 rpm for 10 min to obtain activated brick powder. The specific surface area of ​​the activated brick powder is 500 m². 2 / kg, with a particle size of less than 100μm, wherein the cumulative sieve residue percentage of active brick powder with a particle size of less than 10μm is 50%, and the cumulative sieve residue percentage of active brick powder with a particle size of less than 50μm is 90%, and the activity of the prepared active brick powder is 86%.

[0023] Preparation Example 5 The preparation method of activated brick powder includes the following steps: Waste bricks generated during building demolition are crushed and sieved to obtain waste brick particles with a particle size of less than 5 mm. 100 kg of waste brick particles are dried at 105℃ for 60 min, then cooled for 40 min. The waste brick particles are then ground with 0.75 kg of aluminum chloride at a speed of 50 rpm for 40 min, followed by sieving to obtain modified brick powder. The modified brick powder is then mixed with 600 kg of slag powder and 0.75 kg of aluminum chloride at a speed of 15 rpm for 20 min to obtain activated brick powder. The specific surface area of ​​the activated brick powder is 500 m². 2 / kg, with a particle size of less than 100μm, wherein the cumulative sieve residue percentage of active brick powder with a particle size of less than 10μm is 50%, and the cumulative sieve residue percentage of active brick powder with a particle size of less than 50μm is 90%, and the activity of the prepared active brick powder is 88%.

[0024] The activity test of the activated brick powder in the above preparation example was conducted in accordance with the activity test in GB / T1596-2017 "Fly Ash for Cement and Concrete". Example

[0025] Example 1 A method for preparing a high-ductility cement-based material includes the following preparation steps: (1) Mix 100 kg of cement and 100 kg of active brick powder obtained in Example 1 at a speed of 3 rpm for 20 min to obtain dry mixed powder for later use; (2) Add 2 kg of water-reducing agent, 1 kg of potassium silicate and 1 kg of redispersible latex powder to 300 kg of water and stir evenly to obtain a mixed suspension for later use; (3) Stir the dry powder obtained in step (1) with 100 kg of fine aggregate at 58 rpm for 40 seconds, then add 1 kg of aluminum silicate and continue stirring for 60 seconds, then add the mixed suspension obtained in step (2) and stir at 62 rpm for 2-3 minutes, then stir at 115 rpm for 1-2 minutes to obtain a uniformly flowing premix. (4) Add 5 kg of fiber to the premix obtained in step (3) and stir for 3-4 minutes at 57-63 rpm to obtain a high ductility cement-based material.

[0026] Example 2 A method for preparing a high-ductility cement-based material includes the following preparation steps: (1) Mix 300 kg of cement and 400 kg of active brick powder obtained in Example 1 at a speed of 15 rpm for 10 min to obtain dry mixed powder for later use; (2) Add 3 kg of water-reducing agent, 2 kg of sodium silicate and 3 kg of redispersible latex powder to 400 kg of water and stir evenly to obtain a mixed suspension for later use; (3) Stir the dry powder obtained in step (1) with 700 kg of fine aggregate at 65 rpm for 40 seconds, then add 6 kg of aluminum silicate and continue stirring for 60 seconds, then add the mixed suspension obtained in step (2) and stir at 67 rpm for 2-3 minutes, then stir at 125 rpm for 1-2 minutes to obtain a uniformly flowing premix. (4) Add 10 kg of fiber to the premix obtained in step (3) and stir for 3-4 minutes at 57-63 rpm to obtain a high ductility cement-based material.

[0027] Example 3 A method for preparing a high-ductility cement-based material includes the following preparation steps: (1) Mix 400 kg of cement and 600 kg of the active brick powder obtained in Example 1 at a speed of 15 rpm for 20 min to obtain a dry-mixed powder for later use. (2) Add 5 kg of water-reducing agent, 3 kg of calcium silicate and 5 kg of redispersible latex powder to 500 kg of water and stir evenly to obtain a mixed suspension for later use. (3) Stir the dry powder obtained in step (1) with 1000 kg of fine aggregate at 65 rpm for 40 seconds, then add 10 kg of aluminum silicate and continue stirring for 60 seconds, then add the mixed suspension obtained in step (2) and stir at 67 rpm for 2-3 minutes, then stir at 135 rpm for 1-2 minutes to obtain a uniformly flowing premix. (4) Add 15 kg of fiber to the premix obtained in step (3) and stir for 3-4 minutes at 57-63 rpm to obtain a high ductility cement-based material.

[0028] Example 4 A method for preparing a high-ductility cement-based material differs from Example 2 in that the active brick powder used is the active brick powder obtained in Preparation Example 2.

[0029] Example 5 A method for preparing a high-ductility cement-based material differs from Example 2 in that the active brick powder used is the active brick powder obtained in Preparation Example 3.

[0030] Example 6 A method for preparing a high-ductility cement-based material differs from Example 2 in that the active brick powder used is the active brick powder obtained in Preparation Example 4.

[0031] Example 7 A method for preparing a high-ductility cement-based material differs from Example 2 in that the active brick powder used is the active brick powder obtained in Preparation Example 5.

[0032] Comparison Example Traditional high-ductility cement-based materials consist of cement, fly ash, water, quartz sand, and polyvinyl alcohol fiber in a weight ratio of 1:0.25:0.5:0.8:0.04.

[0033] Comparative Example Comparative Example 1 A method for preparing a high-ductility cement-based material differs from Example 2 in that aluminum sulfate is not added in the preparation of the active brick powder, while all other aspects are the same as in Example 2.

[0034] Comparative Example 2 A method for preparing a high-ductility cement-based material differs from Example 2 in that calcium sulfate is used instead of aluminum sulfate in the preparation of the active brick powder, while all other aspects are the same as in Example 2.

[0035] Comparative Example 3 A method for preparing a high-ductility cement-based material differs from Example 2 in that potassium sulfate is used instead of aluminum sulfate in the preparation of the active brick powder, while all other aspects are the same as in Example 2.

[0036] Comparative Example 4 A method for preparing a high-ductility cement-based material differs from Example 2 in that aluminum silicate salt is not added in step (3), while all other steps are the same as in Example 2.

[0037] Comparative Example 5 A method for preparing a high-ductility cement-based material differs from Example 2 in that potassium silicate is not added in step (2), while all other steps are the same as in Example 2.

[0038] Comparative Example 6 A method for preparing a high-ductility cement-based material differs from Example 2 in that redispersible latex powder is not added in step (2), while all other steps are the same as in Example 2.

[0039] Application examples The high ductility cement-based materials obtained in Examples 1-7, Comparative Examples and Comparative Examples 1-6 were used to prepare raised floors for heating, thereby obtaining Application Examples 1-7 and Application Comparative Examples 1-6. The method of using the high ductility cement-based materials to prepare raised floors for heating is as follows: (1) Surface layer casting: The uniformly flowing premixed material is uniformly cast as the surface layer on the bottom layer of the raised floor mold as the surface layer of the raised floor. The surface layer thickness is 1-3 mm. 1. Structural layer pouring: High-ductility cement-based material is poured in multiple layers as the structural layer of the raised floor. Each layer is no more than 15mm thick. After each layer is poured, it needs to be compacted by roller before pouring the next layer. The interval between each layer pouring is no more than 15 minutes. The slurry of the top structural layer needs to exceed the mold by 1-2mm. Then, it is covered with a film and cured until the specified age to obtain the raised floor.

[0040] Performance testing The equivalent flexural toughness and ultimate elongation of the above-mentioned raised floor were tested after 28 days of curing. The test method for equivalent flexural toughness was in accordance with the relevant provisions of DBJ61-T112-2021 "Technical Specification for Application of High Ductility Concrete"; the ultimate elongation, average crack width and average number of cracks were in accordance with the relevant provisions of JC / T2461-2018 "Test Method for Mechanical Properties of High Ductility Fiber Reinforced Cement-Based Composite Materials".

[0041] The high-temperature resistance test of the raised floor was conducted as follows: First, the raised floor was boiled in a water environment at 60°C for 72 hours, and then the equivalent flexural toughness and ultimate elongation were tested. Second, the raised floor was boiled in a water environment at 100°C for 4 hours, and then the average crack width and average number of cracks were tested. The average crack width and average number of cracks were determined in accordance with the relevant provisions of JC / T2461-2018 "Test Method for Mechanical Properties of High-Ductility Fiber Reinforced Cement-Based Composite Materials". The test results are shown in Table 1.

[0042] Table 1. Performance Test Results of Raised Floor As can be seen from the table above: The raised floor for heating obtained in this application, after being treated in a water environment at 100°C for 4 hours, does not experience brittle fracture and still exhibits the effect of multi-crack development. However, the cement-based material obtained in the comparative example experienced brittle fracture after high-temperature treatment, resulting in a significant increase in the average crack width. Furthermore, the equivalent flexural toughness and ultimate elongation of the raised floor obtained in this application are superior to those of the raised floor obtained in the comparative example. It is evident that the combined use of various raw materials in this application can effectively improve the high-temperature resistance of the raised floor, giving it superior durability, stability, and safety.

[0043] Compared with Comparative Example 1, the equivalent flexural toughness, average number of cracks and average crack width of the raised floor in Comparative Example 1 were significantly reduced. This may be because the activity of the active brick powder obtained by directly grinding the waste brick particles without adding aluminum sulfate is relatively low, resulting in poor cement hydration reaction and a significant reduction in high-temperature resistance.

[0044] Compared with Application Example 2, the equivalent flexural toughness, average number of cracks, and average crack width of Application Example 2-3 are much lower than those of Application Example 2. The reason may be that when calcium sulfate and potassium sulfate activators are used instead of aluminum sulfate activators, the calcium and potassium ions in calcium sulfate and potassium sulfate do not participate in chemical solubilization during the cement hydration reaction. The presence of a large number of low-activity waste brick particles makes the cement hydration reaction incomplete, resulting in poor high-temperature resistance of the raised floor.

[0045] Compared with Application Example 2, when the raw materials of cement-based materials lack aluminum silicate, potassium silicate, or redispersible latex powder, the equivalent flexural toughness, ultimate elongation, average crack width, and average number of cracks of the raised floor are all lower than those of the raised floor in Application Example 2. This shows that the combined use of aluminum silicate, potassium silicate, redispersible latex powder, and active brick powder can effectively improve the high-temperature resistance of high-ductility cement-based materials and improve their crack resistance at high temperatures.

[0046] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A high-ductility cement-based material, characterized in that, The cement-based material comprises the following raw materials in parts by weight: 100-400 parts cement, 100-600 parts activated brick powder, 100-1000 parts fine aggregate, 300-500 parts water, 2-5 parts water-reducing agent, 1-3 parts reinforcing agent, 1-5 parts redispersible latex powder, 1-10 parts heat-resistant filler, and 5-15 parts fiber. The activated brick powder is obtained by the following preparation method: waste bricks are crushed and screened to obtain waste brick particles with a particle size of less than 5 mm. 100-600 parts by weight of waste brick particles are dried and cooled, and then 0.25-0.75 parts by weight of aluminum-based activator are added and ground to obtain modified brick powder. The modified brick powder is mixed evenly with 100-600 parts by weight of slag powder and 0.25-0.75 parts by weight of aluminum-based activator to obtain activated brick powder.

2. The high-ductility cement-based material according to claim 1, characterized in that: The activated brick powder has a particle size of less than 100 μm, wherein the cumulative sieve residue percentage of activated brick powder with a particle size of less than 10 μm is 30-50%, and the cumulative sieve residue percentage of activated brick powder with a particle size of less than 50 μm is 70-90%.

3. The high-ductility cement-based material according to claim 1, characterized in that: The aluminum-based activator is one of aluminum phosphate, aluminum sulfate, potassium aluminum sulfate, aluminum nitrate, and aluminum chloride.

4. The high-ductility cement-based material according to claim 1, characterized in that: The reinforcing agent is one of sodium silicate, potassium silicate, and calcium silicate.

5. The high-ductility cement-based material according to claim 1, characterized in that: The heat-resistant filler is aluminum silicate.

6. The high-ductility cement-based material according to claim 1, characterized in that: The fiber has a length of 10-13 mm and a diameter of 0.04-0.14 mm.

7. The high-ductility cement-based material according to claim 1, characterized in that: The fine aggregate has a particle size of 40-80 mesh.

8. A method for preparing the high-ductility cementitious material according to any one of claims 1-7, characterized in that, The preparation steps include the following: (1) Mix cement and activated brick powder for 10-20 minutes to obtain dry-mixed powder for later use; (2) Add water-reducing agent, reinforcing agent and redispersible latex powder to water and stir evenly to obtain a mixed suspension for later use; (3) Stir the dry powder obtained in step (1) and fine aggregate at 58-65 rpm for 40 seconds, then add heat-resistant filler and continue stirring for 60 seconds, then add the mixed suspension obtained in step (2) and stir at 62-67 rpm for 2-3 minutes, then stir at 115-135 rpm for 1-2 minutes to obtain a uniformly flowing premix. (4) Add fiber to the premix obtained in step (3) and stir for 3-4 minutes at 57-63 rpm to obtain a high ductility cement-based material.

9. A raised floor, characterized in that: It includes a surface layer and a structural layer. The surface layer is cast using the premixed material of claim 8 and has a thickness of 1-3 mm. The structural layer is cast using the high-ductility cement-based material obtained in claim 8 in multiple layers, with each layer having a thickness of no more than 15 mm and a casting interval of no more than 15 minutes between each layer.

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