High-strength modified EPS particle lightweight concrete and preparation method thereof

Abstract

The invention relates to the technical field of building materials, and discloses high-strength modified EPS particle lightweight concrete and a preparation method thereof. The concrete is prepared from the following raw materials in percentage by mass: 0.5 to 0.8 part of fiber, 10 to 13 parts of EPS (Expandable Polystyrene) with the thickness of 0.5 to 5mm, 2 to 4 parts of nano silicon dioxide (NS), 96 to 105 parts of cement, 30 to 42 parts of fly ash, 20 to 30 parts of slag, 50 to 60 parts of river sand, 30 to 35 parts of quartz sand grains, 15 to 22 parts of glass beads, 2.5 to 3.0 parts of water reducing agent and 58 to 64 parts of water, and the water-binder ratio is 0.35 to 0.4. Through cooperation of the fibers and the modified EPS, the interface bonding effect with cement is enhanced, stress transfer is promoted, the fibers are cooperated to play a bridging role, and the mechanical property of the EPS particle concrete is remarkably enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, and in particular to a high-strength modified EPS particle lightweight concrete and a preparation method thereof. Background Art

[0002] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

[0003] Conventional building materials are heavy, have long maintenance cycles, consume high amounts of energy, and are difficult to recycle, making them unable to meet the demand for new building materials. Their application is limited in many structural applications, such as high-rise buildings, large-span structures, underground projects, soft soil foundations, and the renovation of existing buildings. They increase structural loads, construction difficulty, and costs, and affect stability and seismic performance. Compared to traditional concrete, EPS particle concrete is stable, lightweight, and has low water absorption. It possesses excellent energy absorption, ductility, and compressive strain capacity, significantly reducing building weight and improving thermal insulation, offering significant economic, social, and environmental benefits.

[0004] However, the following problems still exist when using EPS particles to prepare lightweight concrete: (1) EPS particle concrete has performance deficiencies such as large porosity and poor mechanical properties; (2) The surface of EPS particles is smooth and hydrophobic, and their bonding with cement paste is poor, which may lead to a decrease in the strength and durability of concrete.

[0005] The commonly used methods for modifying EPS particles and the existing problems are as follows: (1) Chemical modification of EPS particles: Commonly used chemical modifiers include ethylene vinyl acetate (EVA), polyvinyl acetate emulsion, triethanolamine and latex powder emulsion, but the cost of modifiers is high and the processing process may increase the complexity of production; (2) EPS particle sand coating modification: that is, a layer of sand is coated on the surface of EPS particles modified with chemical modifiers. However, the surface of EPS particles coated with sand is rough, and local stress concentration is prone to occur during application, resulting in microcracks, which is not conducive to improving the performance of EPS particle concrete. (3) Shell modification of EPS particles: that is, a spherical "shell" with a certain thickness and strength is prepared on the outer surface of the chemically modified EPS particles, or natural raw materials can be sintered at high temperature to make expanded clay aggregate, but the strength of EPS particle concrete cannot be greatly improved. Summary of the Invention

[0006] The present invention aims to address the current problems of poor modification effects of EPS particles and limited improvement in concrete strength by providing a high-strength modified EPS particle lightweight concrete and a method for preparing the same. The concrete slurry of the present invention exhibits good stability, with EPS particles evenly distributed in the cement slurry. The adhesion between the EPS particles and the concrete is significantly enhanced, and the addition of fibers imparts a certain degree of crack resistance to the concrete, improving the internal cohesion of the concrete and constraining the concrete as a whole. The resulting high-strength modified EPS particle lightweight concrete exhibits a 28d compressive strength exceeding 14 MPa, significantly improving strength.

[0007] The technical solutions of the present invention are as follows: On one hand, the present invention provides a high-strength modified expanded polystyrene (EPS) particle lightweight concrete, which includes the following raw materials in percentage by weight: 0.5-0.8 parts of fiber, 10-13 parts of EPS with a diameter of 0.5-5 mm, 2-4 parts of nano-silicon dioxide (NS), 96-105 parts of cement, 30-42 parts of fly ash, 20-30 parts of slag, 50-60 parts of river sand, 30-35 parts of quartz sand, 15-22 parts of vitrified microspheres, 2.5-3.0 parts of a water reducer, 58-64 parts of water, and a water-cement ratio of 0.35-0.4.

[0008] Preferably, the fibers are basalt fibers and polyvinyl alcohol fibers mixed according to (3-5): (2-3), wherein the basalt fibers have a diameter of 15㎛, a length of 18mm, and a density of 2.65g / cm 3 , elastic modulus is 91Mpa, tensile strength ≥3000Mpa, elongation at break is 3.1%; Polyvinyl alcohol fiber: diameter 15.3㎛, length 12mm, density 1.29g / cm 3 , elastic modulus is 40Mpa, tensile strength ≥1830Mpa, and elongation at break is 7%.

[0009] Preferably, the EPS includes large EPS particles (3-5 mm), medium EPS particles (1-3 mm) and small EPS particles (0.5-1 mm); the mass ratio of large particles, medium particles and small particles is: (4.7-5.3): (2.8-3.2): (1.8-2.2).

[0010] The use of EPS particles of different particle sizes to mix and prepare concrete produces a grading effect. After mixing particles of multiple sizes, the stress is transferred more evenly among the aggregates, avoiding local stress concentration caused by a single particle size and inhibiting crack propagation.

[0011] Preferably, EPS particles are modified with a coupling agent, MA-KH-550, and then coated with NS. The coupling agent acts as a bridge to enhance the interfacial bonding between the EPS particles and the cementitious material. The EPS particles are then coated with small, highly surface-active nano-SiO2, promoting stress transfer between the EPS particles and the cementitious material, thereby increasing the interfacial bonding between the EPS particles and the cementitious material. The addition of fibers further enhances the mechanical properties of EPS particle concrete by bridging the gap. The coupling agent is MA-KH-550 (a combination of γ-aminopropyltriethoxysilane and methyl acrylate in a mass ratio of 1:1.25).

[0012] Using fly ash and slag to replace part of the cement and recycling expanded polystyrene (EPS) to prepare EPS particle concrete can not only effectively solve the "white pollution", but also turn waste into treasure, effectively reduce the weight of concrete, and play a role in thermal insulation, sound insulation, and earthquake resistance.

[0013] MA-KH-550 not only effectively modifies EPS particles and enhances the bond strength between EPS particles and the concrete mortar matrix, but also promotes the encapsulation and modification of NS. Furthermore, the use of this coupling agent can reduce the use of air-entraining agents and thickeners, effectively preventing the phenomenon of EPS particles floating to a certain extent when vibrating to remove bubbles within the concrete.

[0014] By modifying the EPS particles with a coupling agent and coating them with nano-SiO2, the EPS particles are effectively distributed evenly within the concrete matrix, preventing the floating of EPS particles due to their low density. Furthermore, the EPS particle surface is transformed from an inert hydrophobic interface to a highly active hydrophilic interface, significantly improving its bonding strength with the cement matrix and the concrete's compressive strength.

[0015] Preferably, the fly ash is secondary fly ash, ultrafine fly ash, etc.

[0016] Preferably, the cement is ordinary Portland cement.

[0017] Preferably, the water reducer is a high-efficiency water reducer of model FK-A, with a water reducer content of ≥25%, a water content of ≤3%, a total alkali content of ≤3%, a sodium sulfide content of ≤1%, and a sodium chloride content of ≤0.6%.

[0018] Preferably, the fine aggregate is: natural river sand, continuously graded, with an apparent density of 2600 kg / m 3 , the volume density is 1550kg / m 3 , fineness modulus is 2.7, and water content is 2.3%.

[0019] Preferably, the water complies with the "Concrete Mixing Water Standard" (JGJ63-2019).

[0020] Another aspect of the present invention provides a method for modifying EPS particles, comprising the following steps: Step (1): EPS particle pretreatment: The EPS particles are thoroughly cleaned, surface impurities are removed, and then the surface is dried; Step (2): Modification of EPS particles with coupling agent MA-KH-550; Step (3): NS dispersion encapsulates the modified EPS particles.

[0021] According to a preferred embodiment, step (2) includes the following sub-steps: (2.1) Use 2%-3% (mass fraction) of coupling agent, dissolved in 9:1 ethanol:water solvent to prepare a 10% coupling agent solution; (2.2) Mix the cleaned EPS particles with the coupling agent solution in a mass ratio of 1:4 and add them in batches. Stir after each addition to ensure that the particle surface is fully reacted with the coupling agent. Then wash with anhydrous ethanol and deionized water and dry. (2.3) The modified EPS particles are then placed at room temperature for one day to form a siloxane chemical bonding layer, making the particle surface rough.

[0022] According to a preferred embodiment, step (3) includes the following sub-steps: (3.1) Dilute the NS dispersion with deionized water until the volume of NS accounts for 10% of the total volume of the dispersion; (3.2) Soak the modified EPS particles in NS dispersion to ensure that the particle surface is evenly coated with NS; (3.3) Place at room temperature for 1 day to form a NS coating.

[0023] Another aspect of the present invention provides a method for preparing the aforementioned high-strength modified expanded polystyrene (EPS) particle lightweight concrete, comprising the following steps: Step (1): Cement, fly ash, slag and fine aggregate were weighed and added into a concrete mixer and dry mixed for 5 minutes; Step (2): Add modified EPS particles and dry mix for 2 minutes; Step (3): After dry mixing is completed, add 40% of the total water and wet mix for 2 minutes; Step (4): After wet mixing is completed, evenly sprinkle the fibers and stir for 2 minutes to prevent the fibers from clumping and not dispersing; Step (5): add water reducing agent and 60% of the remaining total water and stir for 5 minutes to form concrete slurry; Step (6): inject the slurry into the mold and place it on a vibration table for vibration compaction for about 60 seconds; the finished test block is first placed in a constant temperature drying oven for curing, and then taken out after 24 hours for room temperature curing.

[0024] In the preparation process, first add 40% of water for wet mixing, and finally add the water reducer and the remaining 60% of water and mix well. This not only makes the EPS particles mixed evenly, but also avoids the uneven distribution caused by the floating of EPS particles due to excessive water during the preparation process.

[0025] Compared with the existing technology, the beneficial effects of the present invention are: 1. A high-strength modified EPS particle lightweight concrete and its preparation method. By encapsulating EPS with a coupling agent and NS, the stability of the EPS-cement bond is enhanced. This modification method, without the addition of additional thickeners or air-entraining agents, can improve the drawbacks of traditional EPS concrete, such as poor particle-matrix bonding, low strength, and susceptibility to floating. Combined with fiber bridging, it significantly improves the overall mechanical properties and durability of the concrete. 2. A high-strength modified EPS particle lightweight concrete and its preparation method can fully utilize fly ash, blast furnace slag, and EPS particle waste resources, reduce cement usage, and lower CO2 emissions. The low material price helps reduce construction costs and improve the economic benefits of the project; 3. A high-strength modified EPS particle lightweight concrete and a preparation method thereof. Concrete is prepared by mixing EPS particles of different particle sizes to produce a grading effect. After the multi-size particles are mixed, the stress is transferred more evenly among the aggregates, avoiding local stress concentration caused by a single particle size and inhibiting crack propagation. The preparation process of EPS particle concrete is optimized, and a step-by-step water addition method is adopted. This process effectively reduces problems such as floating and uneven distribution of EPS particles. Furthermore, fibers are added to improve crack resistance and toughness. It is suitable for construction projects with high requirements for lightweight, heat insulation, and seismic resistance, such as prefabricated buildings, wall materials, sound insulation and heat insulation components, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the preparation process of a high-strength modified EPS particle lightweight concrete; Figure 2 It is a form of EPS particles in concrete; Figure 3 A schematic diagram of the pretreatment process of EPS particles. DETAILED DESCRIPTION

[0027] The specific embodiments listed in the present invention are only examples of the present invention, and the present invention is not limited to the specific embodiments described below. For those skilled in the art, any equivalent modifications and substitutions to the embodiments described below are also within the scope of the present invention. Therefore, equivalent transformations and modifications made without departing from the spirit and scope of the present invention should be included within the scope of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. All reagents or instruments without the manufacturer specified are conventional products that can be purchased commercially. In order to better illustrate the present invention, numerous specific details are given in the specific embodiments below. Those skilled in the art should understand that the present invention can also be implemented without certain specific details. In other embodiments, methods, means, equipment and steps well known to those skilled in the art are not described in detail in order to highlight the main purpose of the present invention.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art. Unless otherwise specified, the units used in this specification are International Standard Units, and the numerical values and numerical ranges appearing in this invention should be understood to include the inevitable systematic errors in industrial production.

[0029] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0030] Example 1 A high-strength modified EPS particle lightweight concrete includes the following raw material formula, measured in parts by mass: 0.5 parts of a coupling agent (MA-KH-550), expanded polystyrene (EPS) of different particle sizes: 5 parts of large particles (3-5 mm), 3 parts of medium particles (1-3 mm), and 2 parts of small particles (0.5-1 mm), 3 parts of nano-silica (NS), 100 parts of cement, 30 parts of fly ash, 20 parts of slag, 60 parts of river sand, 30 parts of quartz sand, 15 parts of vitrified microspheres, 2.8 parts of a water reducer, 60 parts of water, and a water-cement ratio of 0.4.

[0031] Table 1. Chemical composition analysis of slag

[0032] Table 2. Chemical composition analysis of fly ash

[0033] Water: Ordinary tap water from Chengdu is used, which complies with the "Concrete Mixing Water Standard" (JGJ63-2019).

[0034] Vitrified microspheres: particle size range 0.2mm-0.5mm, bulk density 180 kg / m³, thermal conductivity 0.042 W / (m・K).

[0035] Quartz sand: particle size 0.6mm, bulk density 1500kg / m 3 .

[0036] The preparation of modified EPS includes the following steps: Step (1): EPS particle pretreatment: The EPS particles were soaked in anhydrous ethanol and cleaned with an ultrasonic cleaner (40kHz, 100W) for 10 minutes to remove surface impurities; the cleaned EPS particles were placed in an oven and dried at 60°C for 2 hours to ensure that the particle surface was dry.

[0037] Step (2): Modification of EPS particles with coupling agent (MA-KH-550): 2%-3% (mass fraction) of coupling agent (MA-KH-550) was dissolved in ethanol:water = 9:1 and mixed to prepare a 10% silane coupling agent solution; the cleaned EPS particles were mixed with the silane solution in a mass ratio of 1:4, placed on a magnetic stirrer, and stirred at 500 rpm for 2 hours to ensure that the particle surface fully reacted with the coupling agent, and then washed with anhydrous ethanol and deionized water and dried; the modified EPS particles were then placed in an oven and dried at 60°C for 2 hours to form a siloxane chemical bonding layer to make the particle surface rough.

[0038] Step (3): NS dispersion coating modified EPS particles: dilute the NS dispersion with deionized water to a concentration of 1%; soak the modified EPS particles in the NS dispersion, place them on a magnetic stirrer, and stir at a speed of 500 rpm for 1 hour to ensure that the particle surface is evenly coated with NS; vacuum dry at 60°C for 2 hours to form a nano-SiO2 coating layer.

[0039] Preparation of a high-strength modified EPS particle lightweight concrete, referring to Figure 1 , including the following steps: Step (1): Cement, fly ash, slag and fine aggregate were weighed and added into a concrete mixer and dry mixed for 5 minutes; Step (2): Add the prepared modified EPS particles and dry mix for 2 minutes; Step (3): After dry mixing is completed, add 40% of the total water and wet mix for 2 minutes; Step (4): add water reducing agent and 60% of the remaining total water and stir for 5 minutes to form concrete slurry; Step (5): inject the slurry into the mold and place it on a vibration table for vibration compaction for about 60 seconds; the finished test block is first placed in a constant temperature drying oven for curing, and then taken out after 24 hours for room temperature curing.

[0040] Example 2 Example 2 is a further improvement of Example 1; the difference is that two types of fibers are added to the formula for synergistic modification. The modified EPS is prepared using the same method as Example 1. A high-strength modified EPS particle lightweight concrete is prepared in a similar manner to Example 1, except that the following step is inserted between steps (3) and (4): After wet mixing is completed, the fibers are evenly sprinkled in batches and stirred for 2 minutes to prevent the fibers from clumping and becoming undispersed.

[0041] Example 3 Example 3 is a further improvement of Example 2; the differences are that the ratio of coupling agent to EPS is reduced, the ratio of NS to EPS is increased, the water-cement ratio is 0.35, and the water reducer dosage is 3. The modified EPS is prepared using the same method as Example 2. A high-strength modified EPS particle lightweight concrete is prepared using the same method as Example 2.

[0042] Example 4 Example 4 is a further improvement on Example 2; the difference is that the ratio of coupling agent to EPS is increased, the ratio of NS to EPS is reduced, the water-cement ratio is 0.38, and the water reducer dosage is 3.2. The modified EPS is prepared using the same method as Example 2. A high-strength modified EPS particle lightweight concrete is prepared using the same method as Example 2. The results are shown in Table 3: Table 3. Formulations of Examples 1-4

[0043] Comparative Example 1 The method is basically the same as Example 2, except that the same EPS particle size is used: the particle size is 1-3 mm. The preparation steps are basically the same as Example 2.

[0044] Comparative Example 2 The preparation steps are basically the same as those in Example 2, except that step (3) is omitted in the preparation of the modified EPS.

[0045] Comparative Example 3 The method is basically the same as Example 2, except that the coupling agent is not used to modify the EPS particles, but the NS dispersion is used to encapsulate the EPS particles. The preparation steps are basically the same as Example 2, except that step (2) is omitted in the preparation of the modified EPS.

[0046] Comparative Example 4 The preparation steps are basically the same as those in Example 2, except that the EPS particles are not modified and ordinary EPS particles are used.

[0047] Comparative Example 5 The preparation steps are basically the same as those in Example 2, except that the EPS particles are modified using only the common KH-550 silane coupling agent. The preparation steps are basically the same as those in Example 2, except that in the modified EPS, the coupling agent used in step (2) is KH-550, and step (3) is omitted.

[0048] Comparative Example 6 The method is basically the same as Example 2, except that the NS is first modified with a coupling agent and then added to the concrete as a cementitious material. The preparation of the modified EPS includes the following steps: Step (1): EPS particle pretreatment: The EPS particles were soaked in anhydrous ethanol and cleaned using an ultrasonic cleaner (40 kHz, 100 W) for 10 minutes to remove surface impurities; the cleaned EPS particles were placed in an oven and dried at 60 ° C for 2 hours to ensure that the particle surface was dry.

[0049] Step (2): Modification of NS with coupling agent (MA-KH-550): 2%-3% (mass fraction) of coupling agent (MA-KH-550) was dissolved in ethanol and water at a ratio of 9:1 to prepare a 10% coupling agent solution. The 10% coupling agent solution was added to the 10% NS dispersion at a mass ratio of 1:4, and the mixture was stirred at room temperature for 1 hour to form an emulsion. The mixture was then washed with anhydrous ethanol and deionized water and dried to obtain surface-modified NS powder.

[0050] The preparation steps of high-strength modified EPS particle lightweight concrete are the same as those in Example 2.

[0051] The formulas of the EPS particle lightweight concrete of Comparative Examples 1-6 are shown in Table 4 below: Table 4. Formula of Comparative Examples 1-6

[0052] The data of each embodiment and comparative example are summarized in the following table: Table 5. Data statistics of examples and comparative examples

[0053] From the above examples, it can be concluded that the dry apparent density grade of the high-strength modified EPS particle lightweight concrete prepared by the present invention is about 1200, the slump can reach about 210, and the compressive strength is about 10 MPa. After adding fiber modification, the compressive strength is about 15 MPa, which is 111.11% higher than the compressive strength of Comparative Example 3 using unmodified EPS concrete.

[0054] The concrete example 2 using modified EPS particles of different particle size distribution also improves the compressive performance by 15.2% compared with the concrete example 1 using modified EPS particles of a single particle size. The morphology of the EPS particles of different particle size distribution in example 2 is as follows: Figure 2 As shown. Example 2 shows a 78.82% increase in compressive strength compared to Comparative Example 2, which uses only coupling agent-modified EPS particles. Example 2 shows a 72.73% increase in compressive strength compared to Comparative Example 3, which uses only NS for wrapping and modification. Example 2 shows a 50.5% increase in compressive strength compared to Comparative Example 6, which uses modified NS as a gelling material. Example 2, which uses the coupling agent MA-KH-550 of the present invention to modify EPS, shows a 36.94% increase in compressive strength compared to Comparative Example 5, which uses conventional coupling agent KH-550 to modify EPS particles.

[0055] Compared to Example 2, Comparative Example 6 differs in its preparation method due to the reaction between NS and the coupling agent. Instead of using a coating method, NS was directly modified with a coupling agent and added directly to the concrete as a cementitious material. The results of Comparative Example 6 were lower in slump and fluidity, and the problem of EPS particles floating up was not effectively addressed, resulting in lower strength than in Example 2. Furthermore, directly modifying NS before coating with EPS reduced the coating effect and strength. Furthermore, in practical applications, using NS as a cementitious material would increase the amount of NS used, leading to higher costs.

[0056] The lower the dry apparent density, the lighter the material, and the better the thermal and sound insulation properties. Comparing the data from the examples and comparative examples shows that the dry apparent density of the concrete prepared in Example 2 of the present invention is lower than that in the comparative example, resulting in lightweight concrete that meets the design density requirements. Furthermore, the slurry of the present invention exhibits excellent stability and high compressive strength. Furthermore, it has little effect on the slump of the concrete, making it suitable for actual on-site construction.

[0057] Compared to using EPS particles of a single particle size, concrete prepared with EPS particles of varying particle sizes exhibits higher ultimate compressive strength, exhibits less degradation, and exhibits a more pronounced reinforcement effect. When fibers are incorporated into lightweight concrete containing EPS particles, analysis based on composite material theory and fiber spacing theory can be used: concrete can be considered a fiber-reinforced system, with the fibers distributed in a three-dimensional, random pattern, forming a fiber skeleton network that effectively penetrates weak points within the concrete, thereby synergizing with the EPS particles to enhance the concrete's mechanical strength. The use of this coupling agent can effectively improve the mechanical properties of EPS concrete, with the reinforcement effect being more pronounced within a certain range. The silane molecules in the coupling agent fill the gaps between the EPS particles and the cementitious base, enhancing the mechanical bond and compactness between the two. The hydrolyzed groups (such as methoxy and acetyl) of the coupling agent react with hydroxyl groups or water in the EPS particles, thereby strengthening the interfacial adhesion between the EPS particles and the concrete matrix.

[0058] Compared to using only silane coupling agents to modify EPS particles, the dual modification method of first modifying with silane coupling agents and then coating EPS particles with NS has significant advantages. NS forms a dense physical barrier by filling interfacial micropores and enhancing surface roughness, and synergistically with the chemical bonding of the coupling agent, significantly improving the interfacial bonding strength and mechanical properties between EPS particles and the cement matrix. At the same time, nano-SiO2 has good volcanic ash activity and reacts with cement hydration product Ca(OH)2 to generate more CSH gel, improving density and long-term durability. The nanolayer can also inhibit the penetration of moisture and harmful ions, improve impermeability and alkali resistance, and give the material better anti-aging and fire resistance, thereby extending the service life of concrete in harsh environments. This invention provides an effective way to develop lightweight, high-strength, durable and environmentally friendly concrete.

[0059] The above-described embodiments merely represent specific implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of protection of the present application. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the technical concept of the present application, and all such variations and improvements fall within the scope of protection of the present application.

Claims

1. A high-strength modified EPS particle lightweight concrete, characterized in that: The invention comprises the following raw materials in percentage by mass: 0.5-0.8 parts of fiber, 10-13 parts of EPS with a diameter of 0.5-5 mm, 2-4 parts of NS, 96-105 parts of cement, 30-42 parts of fly ash, 20-30 parts of slag, 50-60 parts of river sand, 30-35 parts of quartz sand, 15-22 parts of vitrified microspheres, 2.5-3.0 parts of water reducing agent, 58-64 parts of water, and a water-binder ratio of 0.35-0.4; the EPS is modified with a coupling agent MA-KH-550 and then coated with NS, wherein the MA-KH-550 is synthesized from γ-aminopropyltriethoxysilane and methyl acrylate.

2. A high-strength modified EPS particle lightweight concrete according to claim 1, characterized in that: The 0.5-5 mm EPS includes 3-5 mm large-particle EPS, 1-3 mm medium-particle EPS and 0.5-1 mm small-particle EPS; the mass ratio of large particles, medium particles and small particles is: (4.7-5.3): (2.8-3.2): (1.8-2.2).

3. The high-strength modified EPS particle lightweight concrete according to claim 1, characterized in that: The fibers are basalt fibers and polyvinyl alcohol fibers mixed in a ratio of (3-5): (2-3).

4. The high-strength modified EPS particle lightweight concrete according to claim 1, characterized in that: The water reducer is a high efficiency water reducer of model FK-A.

5. A method for modifying EPS particles, characterized in that: The following steps are involved: Step (1): EPS particle pretreatment: The EPS particles are thoroughly cleaned, surface impurities are removed, and then the surface is dried; Step (2): Modify EPS particles with coupling agent MA-KH-550; place EPS particles in coupling agent solution for full reaction; Step (3): NS dispersion wraps the modified EPS particles; the modified EPS particles are immersed in NS dispersion to fully react.

6. The method for modifying EPS particles according to claim 5, characterized in that: The step (2) includes the following sub-steps: (2.1) Use 2%-3% by weight of coupling agent, dissolve it in a solvent with a ratio of ethanol to water = 9:1, and prepare a 10% coupling agent solution; (2.2) Mix the cleaned EPS particles with the coupling agent solution, and add the EPS particles to the coupling agent solution in batches, stirring after each addition until a layer of slurry forms on the EPS particles before adding the next batch, and finally until all the EPS particles are coated with the slurry; (2.3) The modified EPS particles are then left to stand at room temperature for one day to allow the EPS surface to harden and form a siloxane chemical bonding layer, making the particle surface rough.

7. The method for modifying EPS particles according to claim 5, characterized in that: The step (3) includes the following sub-steps: (3.1) Dilute the NS dispersion with deionized water to the desired concentration; (3.2) Soak the modified EPS particles in NS dispersion. NS can form covalent bonds with the active groups of the coupling agent through condensation reaction, so that the particle surface can be evenly and firmly coated with NS; (3.3) Allow to stand at room temperature for 1 day to dry and form a NS coating.

8. A method for preparing high-strength modified EPS particle lightweight concrete, characterized in that: The steps include: Step (1): cement, fly ash, slag and fine aggregate (quartz sand and vitrified microspheres) are weighed and added into a concrete mixer for dry mixing; Step (2): Add modified EPS particles and dry mix; Step (3): After dry mixing is completed, add 40% of the total water volume for wet mixing; Step (4): After wet mixing is completed, evenly sprinkle the fibers and stir to avoid fiber clumping and non-dispersion; Step (5): adding a water reducing agent and 60% of the remaining total water and stirring to form a concrete slurry; Step (6): inject the slurry into the mold and place it on a vibration table for vibration compaction; the finished test block is first placed in a constant temperature drying oven for curing, and after the curing is completed, it is taken out and cured at room temperature.

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