Vinyl acetate emulsion modified EPS particle red mud-based light cementitious material and preparation method thereof

Abstract

This invention discloses a lightweight cementitious material based on red mud and modified EPS particles using polyvinyl acetate emulsion, and its preparation method. The method involves first pre-mixing ordinary silicate cement, carbide slag, red mud, and silica fume in a dry state to obtain a mixed ash; then, adding polyvinyl acetate emulsion diluted with water to EPS particles to pre-modify the surface of the EPS particles; subsequently, mixing polycarboxylate superplasticizer with water to form a mixed solution, and dividing the mixed ash and mixed solution into two equal portions, adding them to the modified EPS particles using a distributed, alternating feeding method. After casting, demolding, and curing, the lightweight cementitious material is obtained. This invention improves the surface wettability and interfacial adhesion of EPS particles through polyvinyl acetate emulsion, enhances the uniformity of EPS particle coating through stepwise, and improves the slurry structure through the gradation control of red mud, carbide slag, and silica fume. The resulting material possesses low density, high strength, low water absorption, and good molding uniformity, achieving efficient resource utilization of solid waste.

Description

Technical Field

[0001] This invention relates to the fields of building materials, resource utilization of solid waste and preparation of lightweight cementitious materials, and particularly to a polyvinyl acetate emulsion modified EPS granules red mud-based lightweight cementitious material and its preparation method. Background Technology

[0002] EPS granules are characterized by low density, low thermal conductivity, and easy availability, and are often used in lightweight thermal insulation cement-based materials. However, the hydrophobic surface of EPS granules and their limited compatibility with inorganic cementitious pastes can easily lead to problems such as floating, agglomeration, insufficient coating, or inadequate interfacial bonding during mixing, thus affecting the uniformity of molding and mechanical properties.

[0003] Red mud is a solid waste generated from the alumina industry, and calcium carbide slag is a byproduct of the acetylene production process via calcium carbide hydrolysis. The resource utilization of both has environmental and engineering value. When red mud and calcium carbide slag are combined with cement and silica fume to form a cementitious material, particle size distribution, alkaline components, micro-fillers, and reactivity all influence the slurry rheology, hardening structure, and interfacial transition zone. Current formulation methods, which simply involve directly mixing EPS particles with the slurry, struggle to stably achieve uniform dispersion and effective surface coating of the EPS particles.

[0004] Therefore, it is necessary to propose a lightweight cementitious material and its preparation method that takes into account solid waste utilization, EPS particle interface modification and cementitious material gradation control, so as to realize the high-value utilization of industrial solid waste and the improvement of the preparation process of lightweight thermal insulation cement-based materials, and provide a green, low-carbon and performance-controllable new composite material technology path for the field of advanced inorganic non-metallic material manufacturing. Summary of the Invention

[0005] This invention provides a polyvinyl acetate emulsion-modified EPS granule red mud-based lightweight cementitious material and its preparation method, in order to overcome the above-mentioned problems.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: A method for preparing a polyvinyl acetate emulsion modified EPS granules red mud-based lightweight cementitious material includes the following steps: S1. Ordinary silicate cement, carbide slag, red mud and silica fume are dried and then premixed to obtain mixed ash; S2. After diluting the polyvinyl acetate emulsion with water, add it to the EPS particles to form a modified layer with adhesive properties on the surface of the EPS particles. S3. Mix the polycarboxylate superplasticizer with water to obtain a mixed solution; S4. Divide the mixed ash described in S1 and the mixed solution described in S3 into two equal parts by mass, and add them alternately to the modified EPS particles described in S2 to form a slurry. S5. The slurry described in S4 is poured into a mold, and after standing, demolding and curing, a polyvinyl acetate emulsion modified EPS particle red mud-based lightweight cementitious material is obtained.

[0007] Furthermore, the red mud, carbide slag, and silica fume mentioned in S1 are subjected to particle size distribution control. The red mud particles with a diameter ≤0.15 mm account for no less than 90% of the total mass; the carbide slag particles with a diameter ≤0.15 mm account for no less than 85% of the total mass; the silica fume particles with a diameter ≤0.15 mm account for no less than 100% of the total mass; the D50 particle size of the red mud is 10-45 μm; the D50 particle size of the carbide slag is 15-60 μm; and the D50 particle size of the silica fume is 0.1-1.0 μm.

[0008] Furthermore, the mass ratio of ordinary silicate cement, carbide slag, red mud, and silica fume described in S1 is 9:5:5:1.

[0009] Furthermore, the mass of the EPS particles described in S2 accounts for 2.00% of the total mass of the cementitious material.

[0010] Furthermore, the amount of water-reducing agent mentioned in S3 is 1.00% of the mass of the cementitious material.

[0011] Furthermore, the total mass of water mentioned in S2 and S3 is 25% of the total mass of the cementitious material.

[0012] Furthermore, the amount of polyvinyl acetate emulsion mentioned in S2 is 0.5%-2.0% of the total mass of the cementitious material.

[0013] Furthermore, the EPS particles described in S2 have a particle size of 3-5 mm and a bulk density of 30-35 kg / m³. 3 Apparent density 8-22 kg / m³ 3 .

[0014] Furthermore, the drying conditions described in S1 are: drying temperature of 40°C; drying time of 24 hours.

[0015] The present invention also provides a lightweight cementitious material based on red mud and modified EPS particles using polyvinyl acetate emulsion prepared by the above method.

[0016] The beneficial effects of this invention are: (1) In this invention, polyvinyl acetate emulsion is used to modify the surface of EPS particles to improve the problems of hydrophobicity and weak adhesion to the gelling paste on the surface of EPS particles. After treatment with polyvinyl acetate emulsion, a modified layer with adhesive effect is formed on the surface of EPS particles, which is conducive to the formation of continuous coating of red mud-based gelling paste on the surface of EPS particles and reduces interfacial debonding.

[0017] (2) The present invention adopts a step-by-step alternating feeding process, in which the mixed ash and mixed solution are added to the modified EPS particles in stages, so that the EPS particles gradually complete the powder coating and liquid phase wetting during the stirring process. Compared with the one-time feeding method, this process can reduce the floating and local exposure of EPS particles, and improve the uniformity of slurry distribution and matrix continuity.

[0018] (3) The present invention controls the EPS particle size within the range of 3-5 mm, which is beneficial to both lightweight and mechanical properties. Using EPS particles with appropriate particle size can reduce the adverse effects of interface defects on strength.

[0019] (4) This invention controls the particle size distribution of red mud, carbide slag and silica fume, which improves the filling effect and slurry homogeneity of the solid waste cementing system. Red mud, carbide slag and silica fume within a suitable particle size range can form a more reasonable particle packing structure and improve the interfacial transition zone around EPS particles.

[0020] (5) This invention improves the utilization value of solid wastes or industrial by-products such as red mud, carbide slag, and silica fume in lightweight cementitious materials. By introducing red mud, carbide slag, and silica fume into the EPS lightweight cementitious system, the amount of ordinary silicate cement used can be reduced, the resource consumption in the material preparation process can be reduced, and the resource utilization of solid waste can be realized. The resulting material has the characteristics of low density, high strength, low water absorption, and good uniformity, and can be used for the preparation of solid waste-based lightweight cementitious materials. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a process flow diagram of the preparation method of the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] The sources of raw materials used in this application are shown in Table 1. All other raw materials not listed are commercially available conventional products. The chemical composition of red mud is shown in Table 2, the chemical composition of carbide slag is shown in Table 3, and the chemical composition of silica fume is shown in Table 4.

[0025] Table 1 Source of Raw Materials

[0026] Table 2 Chemical composition of red mud

[0027] Table 3 Chemical composition of carbide slag

[0028] Table 4 Chemical composition of silica fume

[0029] Example 1 This embodiment provides a polyvinyl acetate emulsion-modified EPS granule red mud-based lightweight cementitious material and its preparation method. The preparation process is as follows: Figure 1 As shown, it includes the following steps: S1. Homogenization pretreatment of the mixed ash: Ordinary Portland cement, carbide slag, red mud, and silica fume are dried in an oven at 40℃ for 24 hours. After drying, 225g of ordinary Portland cement, 125g of carbide slag, 125g of red mud, and 25g of silica fume are added to a cement mortar mixer. High-speed mixing (200 rpm) is performed for 2 minutes to form a homogeneous mixed ash.

[0030] S2. Weigh 5g of water and mix it thoroughly with 5g of polyvinyl acetate emulsion to dilute the polyvinyl acetate emulsion. Weigh 10g of EPS particles, pour the diluted polyvinyl acetate emulsion from S2 into the EPS particles, and mechanically stir slowly (50 rpm) for 2 minutes to modify the surface of the EPS particles. The EPS particles have a particle size of 3-5mm and a bulk density of 30-35kg / m³. 3 Apparent density 8-22 kg / m³ 3 .

[0031] S3. Weigh 120g of water and 5g of polycarboxylate superplasticizer. Mechanically stir the polycarboxylate superplasticizer and water at 200 rpm for 2 minutes until they are evenly mixed.

[0032] S4. Divide the mixed ash from S1 and the mixed solution from S3 into two equal portions by mass. First, slowly add one portion of the mixed ash to the EPS particles and mechanically stir at 100 rpm for 2 minutes. Then, slowly add the same portion of the mixed solution to the EPS particles and mechanically stir at 100 rpm for 3 minutes. Next, slowly add the remaining mixed ash to the EPS particles and mechanically stir at 100 rpm for 2 minutes. Finally, slowly add the remaining mixed solution to the mixture, first mechanically stirring at 100 rpm for 3 minutes, then rapidly mechanically stirring at 200 rpm for 2 minutes.

[0033] S5. Pour the mixed homogeneous slurry into a 40mm×40mm×160mm mold, and gently tap the mold to help release air and compact the slurry. Then let it stand in a laboratory environment for 24 hours. After initial setting, demold the slurry and transfer the test block to a standard curing chamber (temperature 20℃, relative humidity 95%) for 28 days of further curing.

[0034] Furthermore, in the cementitious material, ordinary silicate cement is used to provide the basic hydration cementitious phase; carbide slag is used to provide an alkaline environment and calcium source; red mud participates in matrix formation as a solid waste-based cementitious component and filler component; and silica fume is used to improve the particle filling state and promote the densification of the slurry structure through the activity effect.

[0035] Furthermore, this embodiment controls the particle size distribution of red mud, carbide slag, and silica fume, improving the filling effect and slurry homogeneity of the solid waste cementitious system. Specifically, the mass percentage of red mud particles ≤ 0.15 mm is no less than 90%; the mass percentage of carbide slag particles ≤ 0.15 mm is no less than 85%; and the mass percentage of silica fume particles ≤ 0.15 mm is no less than 100%. The D50 particle size of red mud is 10-35 μm, that of carbide slag is 15-40 μm, and that of silica fume is 0.1-0.5 μm.

[0036] Red mud, carbide slag, and silica fume within a suitable particle size range can form a more reasonable particle packing structure, improving the interfacial transition zone around EPS particles. This results in higher compressive strength, flexural strength, and better uniformity, indicating that particle size distribution control helps improve the structural stability of red mud-based lightweight cementitious materials.

[0037] Example 2 This embodiment provides a polyvinyl acetate emulsion modified EPS particle red mud-based lightweight cementitious material and its preparation method.

[0038] The difference between this embodiment and Embodiment 1 is that the feeding sequence in step S4 is adjusted in this embodiment: First, a portion of the mixed solution is slowly added to the EPS particles and mechanically stirred at 100 rpm for 2 minutes; then, a portion of the mixed ash is slowly added and mechanically stirred at 100 rpm for 3 minutes. Next, the remaining mixed solution is slowly added and mechanically stirred at 100 rpm for 2 minutes; finally, the remaining mixed ash is slowly added, first mechanically stirred at 100 rpm for 3 minutes, then rapidly mechanically stirred at 200 rpm for 2 minutes. All other materials and preparation methods are exactly the same as in Embodiment 1.

[0039] Example 3 This embodiment provides a polyvinyl acetate emulsion modified EPS particle red mud-based lightweight cementitious material and its preparation method.

[0040] The difference between this embodiment and Embodiment 1 is that in this embodiment, the D50 particle size of the red mud is 20-45 μm, the D50 particle size of the carbide slag is 35-60 μm, and the D50 particle size of the silica fume is 0.5-1.0 μm. All other materials and preparation methods are exactly the same as in Embodiment 1.

[0041] Example 4 This embodiment provides a polyvinyl acetate emulsion modified EPS particle red mud-based lightweight cementitious material and its preparation method.

[0042] The difference between this embodiment and Embodiment 1 is that in this embodiment, the mass of the polyvinyl acetate emulsion in S2 is 2.5g (accounting for 0.5% of the mass of the cementitious material), while the remaining materials and preparation methods are exactly the same as in Embodiment 1.

[0043] Example 5 This embodiment provides a polyvinyl acetate emulsion modified EPS particle red mud-based lightweight cementitious material and its preparation method.

[0044] The difference between this embodiment and Embodiment 1 is that in this embodiment, the mass of polyvinyl acetate emulsion in S2 is 10g (accounting for 2% of the mass of the cementitious material), while the remaining materials and preparation methods are exactly the same as in Embodiment 1.

[0045] Comparative Example 1 The difference between this comparative example and Example 1 is that step S4 in this comparative example uses a single-feed method: the mixed ash from S1 is slowly added directly to the EPS particles, and mechanically stirred at 100 rpm for 2 minutes; then the mixed solution from S3 is slowly added, and mechanically stirred at 100 rpm for 3 minutes, followed by rapid mechanical stirring at 200 rpm for 2 minutes. All other materials and preparation methods are exactly the same as in Example 1.

[0046] Comparative Example 2 The difference between this comparative example and Example 1 is that the EPS particles used in step S2 of this comparative example have a particle size of 1-3 mm. The remaining materials and preparation methods are exactly the same as in Example 1.

[0047] Comparative Example 3 The difference between this comparative example and Example 1 is that in this comparative example, polyvinyl acetate emulsion was not added to modify the surface of the EPS particles in step S2. All other materials and preparation methods are exactly the same as in Example 1.

[0048] Comparative Example 4 The difference between this comparative example and Example 1 is that in this example, the D50 particle size of the red mud is 30-55 μm, the D50 particle size of the carbide slag is 55-80 μm, and the D50 particle size of the silica fume is 1-3 μm. All other materials and preparation methods are exactly the same as in Example 1.

[0049] Comparative Example 5: The difference between this comparative example and Example 1 is that in this comparative example, the red mud, carbide slag, and silica fume are not sieved or subjected to gradation control. The remaining materials and preparation methods are exactly the same as in Example 1.

[0050] Table 5 Composition of raw materials in Examples 1-5 and Comparative Examples 1-5

[0051] Performance testing The specimens from Examples 1-5 and Comparative Examples 1-5, after curing, were subjected to the following tests: 1. Density Density testing is divided into dry density and wet density. After curing, the specimen is vacuum dried in a vacuum drying oven at 40℃ for 48 hours until fully dry. Its mass m1 and volume v1 are measured, accurate to 0.1g, and the dry density is calculated using formula (1). After curing, the specimen is immersed in water for 48 hours until saturated. Its mass m2 and volume v2 are measured, accurate to 0.1g, and the wet density is calculated using formula (2). (1) (2) 2. Water absorption rate After curing, the specimens were vacuum dried in a vacuum drying oven at 40°C for 48 hours until they were completely dry. Their mass m1 was measured to be accurate to 0.1g. Then, the specimens were immersed in water for 48 hours until they were saturated with water. Their mass m2 was measured to be accurate to 0.1g. The water absorption rate was calculated using formula (3).

[0052] (3) 3. Compressive and flexural strength In this embodiment, the compressive strength and flexural strength of the lightweight aggregate concrete were measured in accordance with the "Standard for Test Methods of Physical and Mechanical Properties of Concrete" (GB / T 50081-2019).

[0053] The compressive and flexural strengths were determined using a microcomputer-controlled electro-hydraulic servo pressure testing machine (range 2000kN). For the flexural strength test, a three-point loading flexural clamp was installed on the pressure testing machine. The formula for calculating the compressive strength is shown in equation (4). The formula for calculating the flexural strength is shown in equation (5). (4) (5) In the formula, fcu is the cubic compressive strength (MPa), calculated to an accuracy of 0.1 MPa. F is the maximum load at failure (N). A is the bearing area of ​​the specimen (mm²). 2 ff represents the flexural strength (MPa), calculated to an accuracy of 0.1 MPa. L represents the span between supports (mm). b represents the width of the specimen section (mm). h represents the height of the specimen section (mm).

[0054] The arithmetic mean of the measured values ​​of the three specimens in the same group is taken as the representative value of the compressive strength of the specimens in that group. If the difference between the maximum or minimum value and the median value exceeds 15% of the median value, the maximum and minimum values ​​are discarded and the median value is taken as the compressive strength value of the specimens in that group. If the difference between the maximum and minimum values ​​and the median value exceeds 15% of the median value, the test results of that group are deemed invalid and new specimens need to be prepared for retesting.

[0055] 4. Uniformity The uniformity test was performed using the hardened specimen cutting analysis method. The hardened specimen was cut into several small specimens with a thickness of 20mm×40mm×40mm at equal intervals along its length. Three small specimens were randomly selected to measure the dry mass and volume. The dry density of each layer was calculated using formula (1), and then the standard deviation was calculated to analyze the uniformity of aggregate distribution.

[0056] Table 6 Analysis of Specimen Density Test Data

[0057] Table 7 Analysis of water absorption rate test of specimens

[0058] Table 8 Compressive and flexural strength of specimens

[0059] Table 9. Standard deviation analysis of specimen homogeneity

[0060] As shown in Tables 6-9, under the same basic formula and curing regime, the polyvinyl acetate emulsion modified EPS particles, the control of EPS particle size, the control of red mud-carbide slag-silica fume particle gradation, and the step-by-step alternating feeding process all have a significant impact on the material properties.

[0061] Compared to Comparative Example 3, Example 1 differs only in whether or not polyvinyl acetate emulsion is used to modify the surface of EPS particles. Compared to Comparative Example 3, Example 1 exhibits a 20.05% reduction in water absorption, a 51.88% increase in compressive strength, and a 46.10% increase in flexural strength. This indicates that polyvinyl acetate emulsion can improve the wetting and adhesion of EPS particle surfaces, promote the continuous coating of EPS particles by red mud-based cementitious paste, and reduce interconnected pores and weak interfaces at the particle interfaces.

[0062] Example 1 and Comparative Example 1 used identical raw material compositions. The key difference lay in whether or not a step-by-step alternating feeding method of mixed ash and mixed solution was employed. Test results showed that, compared to Comparative Example 1, the compressive strength and flexural strength of Example 1 increased by 25.86% and 30.06%, respectively, while the standard deviation of dry density decreased significantly by 69.11%. This fully demonstrates that the step-by-step alternating feeding mechanism can promote the gradual completion of powder coating and liquid phase wetting of EPS particles, effectively inhibiting particle agglomeration, floating, and local exposure, thereby significantly improving the uniformity of slurry distribution and the overall structural stability of the specimen.

[0063] Example 1 and Comparative Example 2 used the same raw material composition and preparation process, with the core difference being the particle size of the EPS particles. Test results showed that, compared to Comparative Example 2, Example 1 exhibited significantly improved compressive strength and flexural strength by 41.26% and 37.20%, respectively, while water absorption decreased by 9.12% and the standard deviation of dry density decreased by 58.01%. The underlying mechanism for this performance leap is that excessively small EPS particles lead to a sharp increase in specific surface area and the number of interfaces, significantly increasing the difficulty of uniform coating of the slurry and easily forming more weak interface regions internally. Controlling the EPS particle size within the range of 3-5 mm effectively balances the material's lightweight nature, interfacial bonding strength, and overall mechanical properties.

[0064] Examples 1, 4, and 5 together verified the rationality of the polyvinyl acetate emulsion dosage range. Test results showed that when the dosage increased from 0.5% to 1.0%, the compressive strength and flexural strength significantly increased by 14.12% and 14.80%, respectively; however, when the dosage further increased to 2.0%, the compressive strength and flexural strength decreased by 7.92% and 8.00%, respectively. The underlying mechanism of this phenomenon is that too low an emulsion dosage leads to insufficient surface modification of EPS particles; while too high a dosage easily causes local enrichment of organic components at the interface or in the pores, thus hindering the formation of a continuous inorganic cementitious matrix network. Therefore, limiting the polyvinyl acetate emulsion dosage to 0.5%~2.0% of the cementitious material mass has sufficient experimental basis, and the comprehensive performance is best at around 1.0%.

[0065] Based on the data from Examples 1 and 3, as well as Comparative Examples 4 and 5, it is evident that controlling the particle size distribution of red mud, carbide slag, and silica fume is a key factor in improving material performance. Within the particle size range defined in the claims, Example 3 exhibits superior performance: compared to Comparative Example 4, which uses coarser powder particles, its compressive strength increases by 24.25%, its flexural strength increases by 23.30%, and its dry density standard deviation decreases by 52.53%; compared to Comparative Example 5, which was not sieved or gradation-controlled, its compressive strength increases by 33.33%, its flexural strength increases by 28.28%, and its dry density standard deviation decreases by 61.32%. This performance improvement is attributed to the fact that a reasonable powder particle size distribution not only enhances the filling effect between particles and the homogeneity of the slurry distribution but also effectively improves the bonding state of the EPS particle interface, thereby reducing the generation of local pores and lowering the structural dispersion of the molded specimens.

[0066] In summary, this invention comprehensively utilizes multiple technical means, including pre-modifying EPS particles with polyvinyl acetate emulsion, limiting EPS particle size, controlling powder particle gradation, and stepwise alternating feeding, to fundamentally improve the interfacial bonding between EPS particles and red mud-based cementitious slurry, as well as the internal homogeneity of the specimens. Comparative test results show that, compared with a comparative example lacking the corresponding technical features, this invention achieves significant and substantial improvements in key indicators such as water absorption, compressive strength, flexural strength, and dry density uniformity.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a lightweight cementitious material based on red mud and modified polyvinyl acetate emulsion (EPS) particles, characterized in that, Includes the following steps: S1. Ordinary silicate cement, carbide slag, red mud and silica fume are dried and then premixed to obtain mixed ash; S2. After diluting the polyvinyl acetate emulsion with water, add it to the EPS particles to form a modified layer with adhesive properties on the surface of the EPS particles. S3. Mix the polycarboxylate superplasticizer with water to obtain a mixed solution; S4. Divide the mixed ash described in S1 and the mixed solution described in S3 into two equal parts by mass, and add them alternately to the modified EPS particles described in S2 to form a slurry. S5. The slurry described in S4 is poured into a mold, and after standing, demolding and curing, a polyvinyl acetate emulsion modified EPS particle red mud-based lightweight cementitious material is obtained.

2. The preparation method of polyvinyl acetate emulsion modified EPS granules red mud-based lightweight cementitious material according to claim 1, characterized in that, The red mud, carbide slag and silica fume mentioned in S1 are respectively subject to particle size distribution control; The red mud particles with a diameter ≤0.15 mm account for no less than 90% of the total mass; the carbide slag particles with a diameter ≤0.15 mm account for no less than 85% of the total mass; the silica fume particles with a diameter ≤0.15 mm account for no less than 100% of the total mass; the D50 particle size of the red mud is 10-45 μm; the D50 particle size of the carbide slag is 15-60 μm; and the D50 particle size of the silica fume is 0.1-1.0 μm.

3. The preparation method of polyvinyl acetate emulsion modified EPS granules red mud-based lightweight cementitious material according to claim 1, characterized in that, The mass ratio of ordinary silicate cement, carbide slag, red mud and silica fume mentioned in S1 is 9:5:5:

1.

4. The preparation method of polyvinyl acetate emulsion modified EPS granules red mud-based lightweight cementitious material according to claim 1, characterized in that, The EPS particles mentioned in S2 account for 2.00% of the total mass of the cementitious material.

5. The preparation method of polyvinyl acetate emulsion modified EPS granules red mud-based lightweight cementitious material according to claim 1, characterized in that, The amount of water-reducing agent mentioned in S3 is 1.00% of the mass of the cementitious material.

6. The preparation method of polyvinyl acetate emulsion modified EPS granules red mud-based lightweight cementitious material according to claim 1, characterized in that, The total mass of water mentioned in S2 and S3 is 25% of the total mass of the cementitious material.

7. The preparation method of polyvinyl acetate emulsion modified EPS granules red mud-based lightweight cementitious material according to claim 1, characterized in that, The amount of polyvinyl acetate emulsion mentioned in S2 is 0.5%-2.0% of the total mass of the cementitious material.

8. The method for preparing polyvinyl acetate emulsion modified EPS granules red mud-based lightweight cementitious material according to claim 1, characterized in that, The EPS particles described in S2 have a particle size of 3-5 mm and a bulk density of 30-35 kg / m³. 3 Apparent density 8-22 kg / m³ 3 .

9. The method for preparing polyvinyl acetate emulsion modified EPS granules red mud-based lightweight cementitious material according to claim 1, characterized in that, The drying conditions described in S1 are: drying temperature of 40℃ and drying time of 24h.

10. A lightweight cementitious material based on red mud and modified EPS particles using polyvinyl acetate emulsion, characterized in that, It is prepared by the preparation method described in any one of claims 1-9.

Images