A high-strength modified EPS particle lightweight concrete and its preparation method

Abstract

This invention relates to the field of building materials technology. It discloses a high-strength modified EPS particle lightweight concrete and its preparation method. The concrete comprises the following raw materials by mass percentage: 0.5-0.8 parts fiber, 10-13 parts 0.5-5mm EPS, 2-4 parts nano-silica (NS), 96-105 parts cement, 30-42 parts fly ash, 20-30 parts slag, 50-60 parts river sand, 30-35 parts quartz sand, 15-22 parts vitrified microspheres, 2.5-3.0 parts water-reducing agent, 58-64 parts water, and a water-cement ratio of 0.35-0.4. This invention, through the combination of fiber and modified EPS, enhances the interfacial bonding with cement, promotes stress transfer, and synergistically enhances the bridging effect of the fiber, significantly improving the mechanical properties of the EPS particle concrete.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, specifically to a high-strength modified EPS particle lightweight concrete and its preparation method. Background Technology

[0002] The statements in this section provide only background information relevant to the disclosure of this application and may not constitute prior art.

[0003] Conventional building materials are heavy, have long curing cycles, consume a lot of energy, and are difficult to recycle, failing to meet the demands of new building materials. Their application is limited in many structural applications, such as high-rise buildings, large-span structures, underground engineering, soft soil foundations, and renovations of existing buildings, as they increase structural load, construction difficulty, and cost, affecting stability and seismic performance. Compared to traditional concrete, EPS granular concrete is stable, lightweight, and has low water absorption. It possesses excellent energy absorption characteristics, ductility, and compressive strain capacity, significantly reducing building weight and improving insulation, resulting in significant economic, social, and environmental benefits.

[0004] However, the following problems still exist in the current use of EPS particles to prepare lightweight concrete:

[0005] (1) EPS granular concrete has shortcomings in performance, such as large porosity and poor mechanical properties;

[0006] (2) EPS particles have a smooth and hydrophobic surface, resulting in poor adhesion to cement paste, which may lead to a decrease in the strength and durability of concrete.

[0007] The commonly used methods for modifying EPS particles and their existing problems are as follows:

[0008] (1) Chemical modification of EPS particles: Commonly used chemical modifiers include ethylene-vinyl acetate (EVA), polyvinyl acetate emulsion, triethanolamine and latex powder emulsion, etc., but the cost of modifiers is high and the processing may increase the complexity of production.

[0009] (2) EPS particle sand coating modification: that is, the surface of EPS particles modified by chemical modifier is coated with a layer of sand. However, the surface of EPS particles after sand coating is rough, and local stress concentration and micro-cracks are likely to occur during application, which is not conducive to improving the performance of EPS particle concrete.

[0010] (3) EPS particle shell modification: that is, to prepare a spherical "shell" with a certain thickness and strength on the outer surface of the chemically modified EPS particles, or to make ceramsite aggregate by high-temperature sintering of natural raw materials, but the strength of EPS particle concrete still cannot be greatly improved. Summary of the Invention

[0011] The purpose of this invention is to address the problem that current EPS particle modification methods have poor effects and limited strength improvement in concrete, by providing a high-strength modified EPS particle lightweight concrete and its preparation method. The concrete of this invention exhibits good slurry stability, with EPS particles uniformly distributed within the cement paste, significantly enhancing the bonding ability between the EPS particles and the concrete. The addition of fibers gives the concrete certain crack resistance, improves internal bonding strength, and provides overall constraint for the concrete. The prepared high-strength modified EPS particle lightweight concrete exhibits a 28-day compressive strength exceeding 14 MPa, demonstrating a significant strength improvement.

[0012] The technical solution of the present invention is as follows:

[0013] This invention provides a high-strength modified expanded polystyrene (EPS) particle lightweight concrete, comprising the following raw materials by weight percentage: 0.5-0.8 parts fiber, 10-13 parts 0.5-5mm EPS, 2-4 parts nano silica (NS), 96-105 parts cement, 30-42 parts fly ash, 20-30 parts slag, 50-60 parts river sand, 30-35 parts quartz sand particles, 15-22 parts vitrified microspheres, 2.5-3.0 parts water-reducing agent, 58-64 parts water, and a water-cement ratio of 0.35-0.4.

[0014] Preferably, the fibers are a mixture of basalt fibers and polyvinyl alcohol fibers in a ratio of (3-5):(2-3), wherein the basalt fibers have a diameter of 15 mm, a length of 18 mm, and a density of 2.65 g / cm³. 3 Its elastic modulus is 91 MPa, tensile strength is ≥3000 MPa, and elongation at break is 3.1%.

[0015] Polyvinyl alcohol fiber: diameter 15.3 mm, length 12 mm, density 1.29 g / cm³ 3 It has an elastic modulus of 40 MPa, a tensile strength of ≥1830 MPa, and an elongation at break of 7%.

[0016] Preferably, the EPS includes large-particle EPS (3-5mm), medium-particle EPS (1-3mm), and small-particle EPS (0.5-1mm); the mass ratio of large-particle, medium-particle, and small-particle EPS is (4.7-5.3):(2.8-3.2):(1.8-2.2).

[0017] Concrete prepared by mixing EPS particles of different sizes produces a gradation effect. After mixing particles of multiple sizes, stress is transmitted more evenly among the aggregates, avoiding local stress concentration caused by single particle size and inhibiting crack propagation.

[0018] Preferably, the EPS particles are modified with coupling agent MA-KH-550 and then coated with NS. The coupling agent enhances the interfacial adhesion between the EPS particles and the cementitious material through its bridging effect. Furthermore, the small particle size and high surface activity of nano-SiO2 coating the EPS particles promote stress transfer between the EPS particles and the cementitious material, thereby increasing the interfacial adhesion. The addition of fibers further enhances the bridging effect, resulting in a significant improvement in the mechanical properties of EPS particle concrete. The coupling agent is MA-KH-550 (a combination of γ-aminopropyltriethoxysilane and methyl acrylate in a mass ratio of 1:1.25).

[0019] Replacing part of the cement with fly ash and slag and recycling expanded polystyrene (EPS) to prepare EPS particle concrete can not only effectively solve the problem of "white pollution", but also turn waste into treasure, effectively reduce the self-weight of concrete, and play a role in heat insulation, sound insulation and earthquake resistance.

[0020] 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 modification of NS. Furthermore, the use of this coupling agent can reduce the use of air-entraining agents and thickeners, effectively preventing EPS particles from floating to some extent when air bubbles are expelled from the concrete during vibration.

[0021] By modifying EPS particles with coupling agents and encapsulating them with nano-SiO2, the EPS particles can be effectively and uniformly distributed in the concrete matrix, preventing them from floating due to their low density. Furthermore, the surface of the EPS particles is transformed from an inert hydrophobic interface to a highly active hydrophilic interface, significantly improving their bonding strength with the cement matrix and the compressive strength of the concrete.

[0022] Preferably, the fly ash is secondary fly ash, ultrafine fly ash, etc.

[0023] Preferably, the cement is ordinary Portland cement.

[0024] Preferably, the water-reducing agent is a high-efficiency water-reducing agent of model FK-A, with a water-reducing agent content ≥25%, a water content ≤3%, a total alkali content ≤3%, a sodium sulfide content ≤1%, and a sodium chloride content ≤0.6%.

[0025] Preferably, the fine aggregate is: natural river sand, continuously graded, with an apparent density of 2600 kg / m³. 3 Its bulk density is 1550 kg / m³ 3 It has a fineness modulus of 2.7 and a moisture content of 2.3%.

[0026] Preferably, the water is water that conforms to the "Standard for Water for Concrete Mixing" (JGJ63-2019).

[0027] Another aspect of the present invention provides a method for modifying EPS particles, comprising the following steps:

[0028] Step (1): EPS particle pretreatment: Thoroughly clean the EPS particles, remove surface impurities, and then dry the surface.

[0029] Step (2): Modify EPS particles with coupling agent MA-KH-550;

[0030] Step (3): NS dispersion is used to encapsulate modified EPS particles.

[0031] According to a preferred embodiment, step (2) includes the following sub-steps:

[0032] (2.1) Use 2%-3% (mass fraction) of coupling agent, dissolved in a solvent of ethanol:water = 9:1, to prepare a 10% coupling agent solution;

[0033] (2.2) Mix the cleaned EPS particles with the coupling agent solution at a mass ratio of 1:4, add in batches, and stir after each addition to ensure that the particle surface reacts fully with the coupling agent. Then wash with anhydrous ethanol and deionized water and dry.

[0034] (2.3) The modified EPS particles are then placed at room temperature for 1 day to form a siloxane chemical bonding layer, which roughens the particle surface.

[0035] According to a preferred embodiment, step (3) includes the following sub-steps:

[0036] (3.1) Dilute the NS dispersion with deionized water until the volume of NS accounts for 10% of the total volume of the dispersion;

[0037] (3.2) Immerse the modified EPS particles in NS dispersion to ensure that the particle surface is uniformly coated with NS;

[0038] (3.3) Let it sit at room temperature for 1 day to form an NS coating layer.

[0039] Another aspect of the present invention provides a method for preparing high-strength modified expanded polystyrene (EPS) particle lightweight concrete as described above, comprising the following steps:

[0040] Step (1): Weigh the cement, fly ash, slag and fine aggregate and add them together to the concrete mixer for dry mixing for 5 minutes;

[0041] Step (2): Add modified EPS particles and dry mix for 2 minutes;

[0042] Step (3): After dry mixing, add 40% of the total water and wet mix for 2 minutes;

[0043] Step (4): After wet mixing is complete, sprinkle the fiber evenly and stir for 2 minutes to avoid fiber clumping and non-dispersion;

[0044] Step (5): Add water-reducing agent and 60% of the remaining total water and stir for 5 minutes to form concrete slurry;

[0045] Step (6): Inject the slurry into the mold, place it on the vibration table and vibrate it to compact it for about 60 seconds; after the test block is made, first put it into the constant temperature drying oven for curing, and then take it out for room temperature curing after 24 hours.

[0046] In the preparation process, 40% water is added first for wet mixing, and then water-reducing agent and the remaining 60% water are added and mixed evenly. This not only makes the EPS particles evenly mixed, but also avoids the phenomenon of EPS particles floating up due to excessive water during the preparation process, which would cause uneven distribution.

[0047] Compared with existing technologies, the advantages of this invention are:

[0048] 1. A high-strength modified EPS particle lightweight concrete and its preparation method, which improves the stability of the bond between EPS and cement by using a coupling agent and NS to encapsulate EPS. This modification method can improve the shortcomings of traditional EPS concrete, such as poor bonding between particles and matrix, low strength, and easy floating, without the need to add additional thickeners or air-entraining agents. Combined with fiber bridging, it can achieve a significant improvement in the overall mechanical properties and durability of concrete.

[0049] 2. A high-strength modified EPS particle lightweight concrete and its preparation method, which can fully utilize fly ash, blast furnace slag, and EPS particle waste resources, reduce cement consumption, and lower CO2 emissions. Furthermore, the materials are inexpensive, which helps reduce construction costs and improve the economic efficiency of the project.

[0050] 3. A high-strength modified EPS particle lightweight concrete and its preparation method, which uses EPS particles of different sizes to prepare concrete, producing a gradation effect. After mixing particles of multiple sizes, stress is transferred more evenly among the aggregates, avoiding local stress concentration caused by single particle sizes and inhibiting crack propagation. Furthermore, the preparation process of EPS particle concrete has been optimized by adopting a step-by-step water addition method, which effectively reduces problems such as EPS particle floating and uneven distribution. In addition, fibers are added to improve crack resistance and toughness, making it suitable for building projects with high requirements for lightweight, heat insulation, and seismic resistance, such as prefabricated buildings, wall materials, and sound and heat insulation components. Attached Figure Description

[0051] Figure 1 This is a schematic diagram of the preparation process of a high-strength modified EPS particle lightweight concrete.

[0052] Figure 2This describes the morphology of EPS particles in concrete.

[0053] Figure 3 This is a schematic diagram of the pretreatment process for EPS particles. Detailed Implementation

[0054] The specific embodiments listed in this invention are merely examples, and the 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 this invention. Therefore, all equivalent transformations and modifications made without departing from the spirit and scope of this invention should be covered within its scope. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. All reagents or instruments whose manufacturers are not specified are commercially available conventional products. To better illustrate this invention, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that this invention can be practiced even 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 points of this invention.

[0055] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art. Unless otherwise specified, all units used in this specification are International Standard Units (SI), and all numerical values ​​and ranges appearing in this invention should be understood to include systematic errors unavoidable in industrial production.

[0056] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0057] Example 1

[0058] A high-strength modified EPS particle lightweight concrete comprises the following raw material formula by weight: 0.5 parts coupling agent (MA-KH-550), 5 parts expanded polystyrene (EPS) of different particle sizes: 3-5 mm large particles, 3 parts medium particles (1-3 mm), 2 parts small particles (0.5-1 mm), 3 parts nano silica (NS), 100 parts cement, 30 parts fly ash, 20 parts slag, 60 parts river sand, 30 parts quartz sand particles, 15 parts vitrified microspheres, 2.8 parts water-reducing agent, 60 parts water, and a water-cement ratio of 0.4.

[0059] Table 1. Chemical composition analysis of slag

[0060]

[0061] Table 2. Chemical composition analysis of fly ash

[0062]

[0063] Water: Ordinary tap water from Chengdu is used, which meets the "Standard for Water for Concrete Mixing" (JGJ63-2019).

[0064] Vitrified microspheres: particle size range 0.2mm-0.5mm, bulk density 180 kg / m³, thermal conductivity 0.042 W / (m・K).

[0065] Quartz sand: particle size 0.6mm, bulk density 1500kg / m³ 3 .

[0066] The preparation of modified EPS includes the following steps:

[0067] Step (1): EPS particle pretreatment: Soak the EPS particles in anhydrous ethanol and clean them for 10 minutes using an ultrasonic cleaner (40kHz, 100W) to remove surface impurities; put the cleaned EPS particles into an oven and dry them at 60℃ for 2 hours to ensure that the particle surface is dry.

[0068] Step (2): Modification of EPS particles with coupling agent (MA-KH-550): Use 2%-3% (mass fraction) of coupling agent (MA-KH-550) dissolved in ethanol:water = 9:1 to prepare a 10% silane coupling agent solution; mix the cleaned EPS particles with the silane solution at a mass ratio of 1:4, place on a magnetic stirrer and stir at 500 rpm for 2 hours to ensure that the particle surface is fully reacted with the coupling agent, then wash with anhydrous ethanol and deionized water and dry; then put the modified EPS particles into an oven and dry at 60°C for 2 hours to form a siloxane chemical bonding layer, making the particle surface rough.

[0069] Step (3): NS dispersion coating modified EPS particles: Dilute the NS dispersion with deionized water to a concentration of 1%; immerse the modified EPS particles in the NS dispersion, place them on a magnetic stirrer, and stir at 500 rpm for 1 hour to ensure that the particle surface is uniformly coated with NS; vacuum dry at 60℃ for 2 hours to form a nano SiO2 coating layer.

[0070] Preparation of a high-strength modified EPS particle lightweight concrete, referring to Figure 1 It includes the following steps:

[0071] Step (1): Weigh the cement, fly ash, slag and fine aggregate and add them together to the concrete mixer for dry mixing for 5 minutes;

[0072] Step (2): Add the prepared modified EPS particles and dry mix for 2 minutes;

[0073] Step (3): After dry mixing, add 40% of the total water and wet mix for 2 minutes;

[0074] Step (4): Add water-reducing agent and 60% of the remaining total water and stir for 5 minutes to form concrete slurry;

[0075] Step (5): Inject the slurry into the mold, place it on the vibration table and vibrate it to compact it for about 60 seconds; after the test block is made, first put it into the constant temperature drying oven for curing, and then take it out for room temperature curing after 24 hours.

[0076] Example 2

[0077] Example 2 is a further improvement on 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 in Example 1. A method for preparing high-strength modified EPS particle lightweight concrete is similar to that in Example 1, except that the following step is inserted between steps (3) and (4): after wet mixing, fibers are evenly sprinkled in batches and stirred for 2 minutes to avoid fiber clumping and non-dispersion.

[0078] Example 3

[0079] Example 3 is a further improvement on Example 2; the difference lies in reducing the ratio of coupling agent to EPS, increasing the ratio of NS to EPS, setting the water-cement ratio to 0.35, and increasing the water-reducing agent dosage to 3. The modified EPS is prepared using the same method as in Example 2. A method for preparing high-strength modified EPS particle lightweight concrete is also described, using the same method as in Example 2.

[0080] Example 4

[0081] Example 4 is a further improvement on Example 2; the difference lies in increasing the ratio of coupling agent to EPS, decreasing the ratio of NS to EPS, setting the water-cement ratio to 0.38, and increasing the water-reducing agent dosage to 3.2. The modified EPS was prepared using the same method as in Example 2. A high-strength modified EPS particle lightweight concrete was prepared using the same method as in Example 2. The results are shown in Table 3.

[0082] Table 3. Formulations for Examples 1-4

[0083]

[0084] Comparative Example 1

[0085] The preparation process is basically the same as in Example 2, except that EPS particles of the same size (1-3 mm) are used.

[0086] Comparative Example 2

[0087] The preparation process is basically the same as in Example 2, except that a coupling agent is used to modify the EPS particles, but NS dispersion is not used to encapsulate the EPS particles. The preparation steps are basically the same as in Example 2, except that step (3) is omitted in the preparation of the modified EPS.

[0088] Comparative Example 3

[0089] The preparation process is basically the same as in Example 2, except that: instead of using a coupling agent to modify the EPS particles, an NS dispersion is used to encapsulate the EPS particles. The preparation steps are basically the same as in Example 2, except that step (2) is omitted in the preparation of the modified EPS.

[0090] Comparative Example 4

[0091] The preparation process is basically the same as in Example 2, except that no EPS particle modification is performed; ordinary EPS particles are used instead. The preparation steps are basically the same as in Example 2.

[0092] Comparative Example 5

[0093] The process is basically the same as in Example 2, except that the EPS particles are modified using only ordinary KH-550 silane coupling agent. The preparation steps are basically the same as in Example 2, except that in the modified EPS, the coupling agent used in step (2) is KH-550, and step (3) is omitted.

[0094] Comparative Example 6

[0095] The process is essentially the same as in Example 2, except that a coupling agent is used to modify the natural NS first, and then the modified NS is added to the concrete as a cementitious material. The preparation of modified EPS includes the following steps:

[0096] Step (1): EPS particle pretreatment: Immerse the EPS particles in anhydrous ethanol and clean them for 10 minutes using an ultrasonic cleaner (40kHz, 100W) to remove surface impurities; place the cleaned EPS particles in an oven and dry them at 60°C for 2 hours to ensure that the particle surface is dry.

[0097] Step (2): Modification of NS with coupling agent (MA-KH-550): Dissolve 2%-3% (mass fraction) of coupling agent (MA-KH-550) in ethanol:water at a ratio of 9:1 to prepare a 10% coupling agent solution; mix the 10% coupling agent solution with a 10% NS dispersion at a mass ratio of 1:4, and stir the mixture at room temperature for 1 hour to form an emulsion. Then wash with anhydrous ethanol and deionized water and dry to obtain surface-modified NS powder.

[0098] The preparation steps for high-strength modified EPS particle lightweight concrete are the same as in Example 2.

[0099] The formulations of EPS particle lightweight concrete for comparative examples 1-6 are shown in Table 4 below:

[0100] Table 4. Formulations of Comparative Examples 1-6

[0101]

[0102] The statistical data of each embodiment and comparative example are shown in the following table:

[0103] Table 5. Statistical data of examples and comparative examples

[0104]

[0105] From the above embodiments, 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, the compressive strength is about 10 MPa, and the compressive strength after adding fiber modification is about 15 MPa, which is 111.11% higher than the compressive strength of Comparative Example 3 using unmodified EPS concrete.

[0106] Example 2, using modified EPS particles with different particle size gradations, also showed a 15.2% improvement in compressive strength compared to Comparative Example 1, which used modified EPS particles with a single particle size. The morphology of the EPS particles with different particle size gradations in Example 2 is as follows: Figure 2 As shown. Example 2 showed a 78.82% improvement in compressive strength compared to Comparative Example 2, which used only coupling agent-modified EPS particles. Example 2 showed a 72.73% improvement in compressive strength compared to Comparative Example 3, which used only NS coating modification. Example 2 showed a 50.5% improvement in compressive strength compared to Comparative Example 6, which used modified NS as a cementitious material. Example 2, which used the coupling agent MA-KH-550 of this invention to modify EPS, showed a 36.94% improvement in compressive strength compared to Comparative Example 5, which used ordinary coupling agent KH-550 to modify EPS particles.

[0107] Compared to Example 2, Comparative Example 6 differs in its preparation method because the NS and coupling agent need to react. In Comparative Example 6, the coupling agent is directly used to modify the NS, which is then added directly to the concrete as a cementitious material, rather than using an encapsulation method. As a result, Comparative Example 6 exhibits a lower slump, reduced fluidity, and fails to effectively address the issue of EPS particle floating, leading to lower strength than Example 2. Furthermore, directly modifying NS before encapsulating EPS reduces the encapsulation effect, also resulting in lower strength. In addition, in practical applications, using NS as a cementitious material requires increased dosage, leading to higher costs.

[0108] The lower the apparent dry density, the lighter the material and the better its thermal and sound insulation properties. Comparing the data from the examples and comparative examples, it can be concluded that the concrete prepared in Example 2 of this invention has a lower apparent dry density than the concrete in the comparative example, thus achieving lightweight concrete that meets the design density requirements. Furthermore, the slurry in this invention exhibits good stability and high compressive strength. Moreover, it has minimal impact on the concrete slump, making it suitable for practical on-site construction.

[0109] Compared to using EPS particles of a single size, concrete prepared with EPS particles of different sizes exhibits higher ultimate compressive strength, a smaller performance degradation, and a more significant strengthening effect. When EPS particle lightweight concrete incorporates fibers, it can be analyzed based on composite material theory and fiber spacing theory: concrete can be viewed as a fiber-reinforced system, with fibers distributed in a three-dimensional random pattern, forming a fiber skeleton network that effectively penetrates various weak points in the concrete, thereby synergistically improving the mechanical strength of the concrete in conjunction with the EPS particles. Using this coupling agent can effectively improve the mechanical properties of EPS concrete, with a more significant strengthening effect within a certain range. The silane molecules in the coupling agent fill the gaps between the EPS particles and the cementitious matrix, increasing the mechanical interlocking and density between them; the hydrolyzed groups (such as methoxy and acetyl groups) of the coupling agent undergo bonding reactions with the hydroxyl groups or water in the EPS particles, thereby enhancing the interfacial adhesion between the EPS particles and the concrete matrix.

[0110] Compared to modifying EPS particles solely with silane coupling agents, the dual modification method—first modifying with silane coupling agents and then coating EPS particles with nano-silane (NS)—offers significant advantages. NS forms a dense physical barrier by filling interfacial micropores and enhancing surface roughness, synergizing with the chemical bonding of the coupling agent to significantly improve the interfacial bonding strength and mechanical properties between EPS particles and the cement matrix. Simultaneously, nano-SiO2 exhibits excellent pozzolanic activity and reacts with cement hydration products Ca(OH)2 to generate more CSH gel, enhancing density and long-term durability. The nanolayer also inhibits the penetration of moisture and harmful ions, improving impermeability and alkali resistance, and endowing the material with better anti-aging and fire-resistant properties, thereby extending the service life of concrete in harsh environments. This invention provides an effective approach for the development of lightweight, high-strength, durable, and environmentally friendly concrete.

[0111] The embodiments described above merely illustrate specific implementation methods of this application, and while the descriptions are detailed and specific, they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the technical solution of this application, and these modifications and improvements all fall within the scope of protection of this application.

Claims

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

2. The high-strength modified EPS particle lightweight concrete according to claim 1, characterized in that, The 0.5-5mm EPS includes large EPS particles of 3-5mm, medium EPS particles of 1-3mm, and small EPS particles of 0.5-1mm; the mass ratio of large, medium, 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 fiber is a mixture of basalt fiber and polyvinyl alcohol fiber 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-reducing agent is a high-efficiency water-reducing agent with model number FK-A.

5. A method for modifying EPS particles, characterized in that, Includes the following steps: Step (1): EPS particle pretreatment: Thoroughly clean the EPS particles, remove surface impurities, and then dry the surface. Step (2): Modify EPS particles with coupling agent MA-KH-550; place EPS particles in the coupling agent solution for full reaction; Step (3): The modified EPS particles are coated with NS dispersion; the modified EPS particles are immersed in NS dispersion to react fully.

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

7. The method for modifying EPS particles according to claim 5, characterized in that, Step (3) includes the following sub-steps: (3.1) Dilute the NS dispersion with deionized water to the required concentration; (3.2) The modified EPS particles are immersed in NS dispersion. NS can form covalent bonds with the active groups of the coupling agent through condensation reaction, so that NS can be uniformly and firmly coated on the particle surface. (3.3) Let it stand at room temperature for 1 day to dry, forming an NS coating layer.

8. A method for preparing high-strength modified EPS particle lightweight concrete, characterized in that, Includes the following steps: Step (1): Weigh the cement, fly ash, slag, river sand, quartz sand particles and vitrified microspheres and add them together to the concrete mixer for dry mixing; Step (2): Add modified EPS particles and dry mix; the modified EPS particles are modified by the following steps: modified by coupling agent MA-KH-550 and then coated with NS; Step (3): After dry mixing, add 40% of the total water volume for wet mixing; Step (4): After wet mixing is complete, sprinkle the fiber evenly and stir to avoid the fiber from clumping and not dispersing; Step (5): Add water-reducing agent and 60% of the remaining total water and mix to form concrete slurry; Step (6): Inject the slurry into the mold and place it on the vibration table to vibrate and compact it; after the test block is made, first put it into the constant temperature drying oven for curing, and after curing, take it out for room temperature curing.

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