Anti-crack durable highway subgrade material and preparation method thereof

Abstract

The invention discloses an anti-crack durable highway subgrade material and a preparation method thereof, and belongs to the technical field of concrete, the anti-crack durable highway subgrade material comprises the following raw materials by weight: 10-15 parts of steel slag, 20-30 parts of fly ash, 15-20 parts of electrolytic manganese residue, 3-5 parts of modified rubber particles, 1-2 parts of nano SiO2, 5-20 parts of reinforced fiber, and 0.2-1.5 parts of an additive. High-value utilization of solid waste is achieved through a steel slag-fly ash-electrolytic manganese slag ternary gel system, a multi-scale anti-cracking network is formed through cooperation with the modified rubber particles and the composite reinforced fibers, and the toughness and anti-fatigue performance of the material are remarkably improved. The material has the characteristics of excellent mechanical property, environment friendliness and long-acting durability, the raw materials are easy to obtain, the preparation method is simple, and the material is convenient to popularize and apply.

Description

Technical Field

[0001] The invention belongs to the technical field of concrete, and in particular relates to a crack-resistant and durable highway subgrade material and a preparation method thereof. Background Art

[0002] Currently, crack-resistant, durable highway subgrade materials have become a core requirement for transportation infrastructure construction. Key applications include cement-stabilized crushed stone, asphalt-stabilized base layers, and new composite materials. Existing technologies improve crack resistance in cement-based materials by incorporating fibers (such as polypropylene fibers and steel fibers) or expansion agents, but these materials suffer from issues such as difficulty controlling shrinkage cracks and insufficient toughness. Asphalt-based materials rely on high-viscosity modified asphalt to improve durability, but face a conflicting balance between high-temperature stability and low-temperature crack resistance. While recycled industrial solid waste materials (such as steel slag and fly ash) offer environmental advantages, their volume stability and long-term performance still fall short of optimal use requirements.

[0003] Existing technologies for highway subgrade materials face challenges in synergistically optimizing crack resistance alongside mechanical properties such as strength and stiffness. High-modulus materials, for example, are prone to brittle cracking. Furthermore, the mechanisms of material degradation under extreme climate conditions (freeze-thaw cycles and alternating wet-dry conditions) are insufficiently studied. Furthermore, existing standards for highway subgrade materials are mostly based on short-term testing and lack models correlating them with actual road performance.

[0004] Therefore, how to provide a crack-resistant and durable highway subgrade material with good mechanical properties and strong environmental adaptability is a technical problem that those skilled in the art urgently need to solve. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention proposes a crack-resistant and durable highway subgrade material and a preparation method thereof.

[0006] To achieve the above objectives, the present invention provides the following technical solutions:

[0007] A crack-resistant and durable highway subgrade material comprises the following raw materials in parts by weight:

[0008] 10-15 parts of steel slag, 20-30 parts of fly ash, 15-20 parts of electrolytic manganese slag, 3-5 parts of modified rubber particles, 1-2 parts of nano-SiO2, 5-20 parts of reinforcing fiber, and 0.2-1.5 parts of admixture.

[0009] Beneficial effects: The present invention adopts a ternary system of steel slag + fly ash + electrolytic manganese slag. Steel slag provides early strength, fly ash optimizes long-term performance, and electrolytic manganese slag enhances corrosion resistance, forming a high-strength, low-shrinkage composite gelling system. It not only realizes the resource utilization of industrial solid waste, but also forms a dense structure through synergistic hydration reaction, improves the mechanical properties of the material, and reduces the drying shrinkage rate. At the same time, the present invention adds modified rubber particles to improve the matrix interface bonding strength, and the modified rubber particles and nano-SiO2 work together. The former absorbs stress waves to reduce impact damage, and the latter fills micropores and promotes hydration reaction, thereby increasing the material density. Secondly, the reinforcing fibers in the present invention can form a multi-scale anti-crack network, greatly improving the flexural strength of the material. In addition, the admixtures in the present invention synergistically mineralize on the nucleation sites provided by nano-SiO2, achieving a crack self-repairing effect, while the retarder and shrinkage reducer regulate the hydration process, greatly reducing the drying shrinkage rate. The components in the present invention work together to make the material have high mechanical properties, excellent durability and environmental friendliness.

[0010] Preferably, the reinforcing fiber is obtained by mixing basalt fiber, straw fiber and alloy fiber in a mass ratio of 3:2:1.

[0011] Preferably, the alloy fiber is one or more of steel fiber, titanium alloy fiber, and memory alloy fiber.

[0012] Beneficial effects: The present invention constructs a multi-level reinforcement network with composite fibers of special proportions, specifically basalt fibers provide the main bearing capacity, straw fibers improve toughness, and memory alloy fibers generate prestress when the temperature difference changes, greatly improving the material's crack resistance.

[0013] Preferably, the admixture includes 0.1-0.5 parts of a microbial system and 0.1-1 parts of a functional additive.

[0014] Preferably, the microbial system comprises Bacillus, Pseudomonas and calcium lactate; and / or,

[0015] The functional additives include retarders and shrinkage reducers.

[0016] More preferably, the mass ratio of the Bacillus, Pseudomonas and calcium lactate is 0.8:1.2:5;

[0017] The retarder is one or more of lignin sulfonate, sodium gluconate and aminotri(methylene)phosphonic acid;

[0018] The shrinkage reducing agent is one or more of polyoxyethylene alkyl ether, polyethylene glycol PEG-400, and ethylene oxide-propylene oxide copolymer.

[0019] Beneficial Effects: The present invention utilizes a dual-strain microbial system (Bacillus + Pseudomonas) in conjunction with calcium lactate to form a dual mineralized deposit (CaCO3 + biofilm) at cracks, enhancing the material's self-healing properties. Furthermore, Bacillus and Pseudomonas effectively accelerate the dissolution and conversion of minerals such as free calcium oxide (CaO) in steel slag, fly ash, and electrolytic manganese slag, thereby reducing the f-CaO (free calcium oxide) content in these materials and improving the product's volume stability.

[0020] Preferably, the modified rubber particles are obtained by crushing waste tires and then treating them with a silane coupling agent.

[0021] Beneficial effects: The addition of modified rubber particles in the present invention can improve the interfacial bonding strength, while maintaining the elasticity of the material and avoiding strength loss.

[0022] A method for preparing a crack-resistant and durable highway subgrade material comprises the following steps:

[0023] The steel slag, fly ash and electrolytic manganese slag are pretreated and then mixed with nano-SiO2 to obtain a dry mix; water is added to the dry mix to obtain a slurry, reinforcing fibers and modified rubber particles are added and mixed evenly, and then an admixture is added. After stirring evenly, the mixture is spread, vibrated and cured to obtain the crack-resistant and durable highway subgrade material.

[0024] Preferably, the water is added at a water-to-binder ratio of 0.3-0.45.

[0025] Preferably, the pretreatment is as follows: crushing the steel slag, fly ash and electrolytic manganese slag, screening out impurities, and then drying them to complete the pretreatment.

[0026] Preferably, the maintenance includes initial maintenance and long-term maintenance;

[0027] Wherein, the initial maintenance includes the following steps:

[0028] Under the conditions of 18-25℃ and humidity ≥90%, cover with wet cloth and maintain for 48 hours, then remove the film and spray water to keep it moist.

[0029] More preferably, the long-term curing is natural curing under outdoor conditions for 7-28 days.

[0030] Beneficial effects: The preparation method provided by the present invention can ensure the activity of raw materials, balance workability and strength, make the cementitious material fully hydrated, and at the same time effectively improve the activity of microorganisms, realize the self-repair effect of the material, and ensure the durability and crack resistance of the product.

[0031] Compared with the prior art, the present invention has the following advantages and technical effects:

[0032] This invention provides a crack-resistant, durable highway subgrade material and its preparation method. This material utilizes a ternary cementitious system of steel slag, fly ash, and electrolytic manganese slag to achieve high-value utilization of solid waste. Modified rubber particles and composite reinforcing fibers form a multi-scale crack-resistant network, significantly improving the material's toughness and fatigue resistance. The addition of nano-SiO2 optimizes the microstructure, synergizing with a microbial self-repair system to achieve crack self-healing. Functional additives further reduce drying shrinkage. This material combines excellent mechanical properties with environmental friendliness and long-term durability. Its readily available raw materials and simple preparation method facilitate its widespread application. DETAILED DESCRIPTION

[0033] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0034] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with specific embodiments.

[0035] An embodiment of the present invention discloses a crack-resistant and durable highway subgrade material, comprising the following raw materials in parts by weight: 10-15 parts of steel slag, 20-30 parts of fly ash, 15-20 parts of electrolytic manganese slag, 3-5 parts of modified rubber particles, 1-2 parts of nano-SiO2, 5-20 parts of reinforcing fiber, and 0.2-1.5 parts of an admixture.

[0036] In an optional embodiment, the crack-resistant and durable highway subgrade material includes the following raw materials in parts by weight: 13 parts of steel slag, 25 parts of fly ash, 17 parts of electrolytic manganese slag, 4 parts of modified rubber particles, 1.5 parts of nano-SiO2, 12 parts of reinforcing fiber (basalt fiber, straw fiber and steel fiber mixed in a mass ratio of 3:2:1), admixtures including 0.3 parts of a microbial system (Bacillus, Pseudomonas and calcium lactate mixed in a mass ratio of 0.8:1.2:5) and 0.2 parts of a functional additive (lignin sulfonate and polyoxyethylene alkyl ether mixed in a mass ratio of 1:1).

[0037] In another optional embodiment, the crack-resistant and durable highway subgrade material includes the following raw materials in parts by weight: 15 parts of steel slag, 20 parts of fly ash, 15 parts of electrolytic manganese slag, 5 parts of modified rubber particles, 1 part of nano-SiO2, 20 parts of reinforcing fiber (basalt fiber, straw fiber and titanium alloy fiber mixed in a mass ratio of 3:2:1), admixtures including 0.1 part of a microbial system (Bacillus, Pseudomonas and calcium lactate mixed in a mass ratio of 0.8:1.2:5) and 0.1 part of a functional additive (sodium gluconate and polyoxyethylene alkyl ether mixed in a mass ratio of 1:1).

[0038] In another optional embodiment, the crack-resistant and durable highway subgrade material includes the following raw materials in parts by weight: 10 parts of steel slag, 30 parts of fly ash, 20 parts of electrolytic manganese slag, 3 parts of modified rubber particles, 2 parts of nano-SiO2, 5 parts of reinforcing fiber (basalt fiber, straw fiber and memory alloy fiber mixed in a mass ratio of 3:2:1), admixtures including 0.5 parts of a microbial system (Bacillus, Pseudomonas and calcium lactate mixed in a mass ratio of 0.8:1.2:5) and 1 part of a functional additive (aminotrimethylphosphonic acid and polyethylene glycol PEG-400 mixed in a mass ratio of 1:1).

[0039] In a preferred embodiment, the reinforcing fiber is obtained by mixing basalt fiber, straw fiber and alloy fiber in a mass ratio of 3:2:1.

[0040] In a preferred embodiment, the alloy fiber is one or more of steel fiber, titanium alloy fiber, and memory alloy fiber.

[0041] In a preferred embodiment, the admixture includes 0.1-0.5 parts of a microbial system and 0.1-1 parts of a functional additive.

[0042] In a preferred embodiment, the microbial system comprises Bacillus, Pseudomonas and calcium lactate; and / or,

[0043] The functional additives include retarders and shrinkage reducers.

[0044] In a more preferred embodiment, the mass ratio of the Bacillus, Pseudomonas and calcium lactate is 0.8:1.2:5.

[0045] In an optional embodiment, the retarder is one or more of lignin sulfonate, sodium gluconate and aminotri(methylenephosphonic) acid.

[0046] In an optional embodiment, the shrinkage reducing agent is one or more of polyoxyethylene alkyl ether, polyethylene glycol PEG-400, and ethylene oxide-propylene oxide copolymer.

[0047] In a preferred embodiment, the modified rubber particles are obtained by crushing waste tires and then treating them with a silane coupling agent.

[0048] The present invention also discloses a method for preparing a crack-resistant and durable highway subgrade material, comprising the following steps:

[0049] The steel slag, fly ash and electrolytic manganese slag are pretreated and then mixed with nano-SiO2 to obtain a dry mix; water is added to the dry mix to obtain a slurry, reinforcing fibers and modified rubber particles are added and mixed evenly, and then an admixture is added. After stirring evenly, the mixture is spread, vibrated and cured to obtain the crack-resistant and durable highway subgrade material.

[0050] In a preferred embodiment, the water is added at a water-to-binder ratio of 0.3-0.45.

[0051] In a preferred embodiment, the pretreatment is as follows: crushing the steel slag, fly ash and electrolytic manganese slag, screening out impurities, and then drying them to complete the pretreatment.

[0052] In a preferred embodiment, the curing includes initial curing and long-term curing;

[0053] Wherein, the initial maintenance includes the following steps:

[0054] Under the conditions of 18-25℃ and humidity ≥90%, cover with wet cloth and maintain for 48 hours, then remove the film and spray water to keep it moist.

[0055] In a more preferred embodiment, the long-term curing is natural curing under outdoor conditions for 7-28 days.

[0056] Unless otherwise specified, the raw materials in the examples of the present invention were purchased from commercial sources.

[0057] Among them, steel slag was purchased from MCC General Research Institute of Building and Construction Co., Ltd.

[0058] The fly ash was purchased from the Fly Ash Branch of Chongqing Luohuang Power Plant of Huaneng Group.

[0059] Electrolytic manganese slag was purchased from Ningxia Tianyuan Manganese Industry Group Co., Ltd.

[0060] The preparation method of modified rubber particles comprises the following steps:

[0061] The waste tires are crushed into a particle size of 600-800 mesh, then immersed in an ethanol solution of a silane coupling agent (KH-550) with a mass concentration of 6% for modification for 2 hours, and then dried to obtain modified rubber particles.

[0062] Unless otherwise specified, room temperature or normal temperature in the embodiments of the present invention refers to 25±3°C.

[0063] Example 1

[0064] A crack-resistant and durable highway subgrade material comprises the following raw materials in parts by weight:

[0065] 13 parts of steel slag, 25 parts of fly ash, 17 parts of electrolytic manganese slag, 4 parts of modified rubber particles, 1.5 parts of nano-SiO2, 12 parts of reinforcing fiber (basalt fiber, straw fiber and steel fiber mixed in a mass ratio of 3:2:1), admixtures including 0.3 parts of microbial system (Bacillus, Pseudomonas and calcium lactate mixed in a mass ratio of 0.8:1.2:5) and 0.2 parts of functional additives (lignin sulfonate and polyoxyethylene alkyl ether mixed in a mass ratio of 1:1).

[0066] A method for preparing a crack-resistant and durable highway subgrade material comprises the following steps:

[0067] (1) Raw material pretreatment: crush the steel slag to a particle size of ≤5mm, remove residual iron by magnetic separation, and dry it to a moisture content of <1%; pass the fly ash through a 0.075mm sieve to remove unburned carbon particles; grind the electrolytic manganese slag to a specific surface area of ​​≥400m 2 / kg, dried at 105℃ to remove free moisture.

[0068] (2) Pretreated steel slag, fly ash and electrolytic manganese slag are mixed with nano-SiO2 to obtain a dry mix; water is added to the dry mix at a water-to-binder ratio of 0.35 to obtain a slurry, reinforcing fibers and modified rubber particles are added and mixed evenly, and then an admixture is added. After stirring evenly, the mixture is spread and vibrated to a density of ≥95%, and covered with a wet cloth for curing for 48 hours at 18-25°C and a humidity of ≥90%, and then the film is removed, and water is sprayed to keep it moist to complete the initial curing, and then naturally cured for 7-28 days under outdoor conditions to obtain the crack-resistant and durable highway subgrade material.

[0069] Example 2

[0070] A crack-resistant and durable highway subgrade material comprises the following raw materials in parts by weight:

[0071] 15 parts of steel slag, 20 parts of fly ash, 15 parts of electrolytic manganese slag, 5 parts of modified rubber particles, 1 part of nano-SiO2, 20 parts of reinforcing fiber (basalt fiber, straw fiber and titanium alloy fiber mixed in a mass ratio of 3:2:1), admixtures including 0.1 part of microbial system (Bacillus, Pseudomonas and calcium lactate mixed in a mass ratio of 0.8:1.2:5) and 0.1 part of functional additives (sodium gluconate and polyoxyethylene alkyl ether mixed in a mass ratio of 1:1).

[0072] A method for preparing a crack-resistant and durable highway subgrade material comprises the following steps:

[0073] (1) Raw material pretreatment: crush the steel slag to a particle size of ≤5mm, remove residual iron by magnetic separation, and dry it to a moisture content of <1%; pass the fly ash through a 0.075mm sieve to remove unburned carbon particles; grind the electrolytic manganese slag to a specific surface area of ​​≥400m 2 / kg, dried at 105℃ to remove free moisture.

[0074] (2) Pretreated steel slag, fly ash and electrolytic manganese slag are mixed with nano-SiO2 to obtain a dry mix; water is added to the dry mix at a water-to-binder ratio of 0.3 to obtain a slurry, reinforcing fibers and modified rubber particles are added and mixed evenly, and then an admixture is added. After stirring evenly, the mixture is spread and vibrated to a density of ≥95%, and covered with a wet cloth for curing for 48 hours at 18-25°C and a humidity of ≥90%, and then the film is removed, and water is sprayed to keep it moist to complete the initial curing, and then naturally cured for 7-28 days under outdoor conditions to obtain the crack-resistant and durable highway roadbed material.

[0075] Example 3

[0076] A crack-resistant and durable highway subgrade material comprises the following raw materials in parts by weight:

[0077] 10 parts of steel slag, 30 parts of fly ash, 20 parts of electrolytic manganese slag, 3 parts of modified rubber particles, 2 parts of nano-SiO2, 5 parts of reinforcing fiber (basalt fiber, straw fiber and memory alloy fiber mixed in a mass ratio of 3:2:1), 0.5 parts of admixtures including a microbial system (Bacillus, Pseudomonas and calcium lactate mixed in a mass ratio of 0.8:1.2:5) and 1 part of a functional additive (aminotrimethylenephosphonic acid and polyethylene glycol PEG-400 mixed in a mass ratio of 1:1).

[0078] A method for preparing a crack-resistant and durable highway subgrade material comprises the following steps:

[0079] (1) Raw material pretreatment: crush the steel slag to a particle size of ≤5mm, remove residual iron by magnetic separation, and dry it to a moisture content of <1%; pass the fly ash through a 0.075mm sieve to remove unburned carbon particles; grind the electrolytic manganese slag to a specific surface area of ​​≥400m 2 / kg, dried at 105℃ to remove free moisture.

[0080] (2) Pretreated steel slag, fly ash and electrolytic manganese slag are mixed with nano-SiO2 to obtain a dry mix; water is added to the dry mix at a water-to-binder ratio of 0.45 to obtain a slurry, reinforcing fibers and modified rubber particles are added and mixed evenly, and then an admixture is added. After stirring evenly, the mixture is spread and vibrated to a density of ≥95%, and covered with a wet cloth for curing for 48 hours at 18-25°C and a humidity of ≥90%, and then the film is removed, and water is sprayed to keep it moist to complete the initial curing, and then naturally cured for 7-28 days under outdoor conditions to obtain the crack-resistant and durable highway subgrade material.

[0081] Comparative Example 1

[0082] A crack-resistant and durable highway subgrade material is different from Example 1 only in that the electrolytic manganese slag is replaced with fly ash. The remaining raw materials and addition amounts are the same as those in Example 1.

[0083] A method for preparing a crack-resistant and durable highway roadbed material is different from Example 1 only in that the above-mentioned raw materials are used, and the remaining process steps and parameters are the same as those in Example 1.

[0084] Comparative Example 2

[0085] A crack-resistant and durable highway subgrade material differs from Example 1 only in that the microbial system is replaced by a mixture of Bacillus and calcium lactate in a mass ratio of 1:8:2:5. The remaining raw materials and addition amounts are the same as those in Example 1.

[0086] A method for preparing a crack-resistant and durable highway roadbed material is different from Example 1 only in that the above-mentioned raw materials are used, and the remaining process steps and parameters are the same as those in Example 1.

[0087] Comparative Example 3

[0088] A crack-resistant and durable highway subgrade material differs from Example 1 only in that the electrolytic manganese slag is replaced with fly ash and the addition of a microbial system is omitted. The remaining raw materials and addition amounts are the same as those in Example 1.

[0089] A method for preparing a crack-resistant and durable highway roadbed material is different from Example 1 only in that the above-mentioned raw materials are used, and the remaining process steps and parameters are the same as those in Example 1.

[0090] Comparative Example 4

[0091] A crack-resistant and durable highway subgrade material is different from Example 1 only in that the rubber particles and other materials are replaced with fly ash. The remaining raw materials and addition amounts are the same as those in Example 1.

[0092] A method for preparing a crack-resistant and durable highway roadbed material is different from Example 1 only in that the above-mentioned raw materials are used, and the remaining process steps and parameters are the same as those in Example 1.

[0093] Comparative Example 5

[0094] A crack-resistant and durable highway subgrade material differs from Example 1 only in that the reinforcing fiber is a mixture of basalt fiber and steel fiber in a mass ratio of 1:1. The remaining raw materials and addition amounts are the same as those in Example 1.

[0095] A method for preparing a crack-resistant and durable highway roadbed material is different from Example 1 only in that the above-mentioned raw materials are used, and the remaining process steps and parameters are the same as those in Example 1.

[0096] Technical effects:

[0097] The highway subgrade materials obtained after curing for 28 days in Examples 1-3 and Comparative Examples 1-5 were tested for compressive strength according to GB / T17671-1999 "Test Method for Cement Mortar Strength (ISO Method)", tested for shrinkage at 28 days according to JTG E51-2009 "Test Procedure for Stabilized Materials of Inorganic Binders for Highway Engineering", recorded for initial cracking time according to ASTM C1581 "Standard Test Method for Restrained Shrinkage Cracking of Concrete", and subjected to freeze-thaw cycle testing at -20°C to 20°C for 300 cycles according to GB / T50082-2009 "Test Method for Long-term Properties and Durability of Ordinary Concrete", measuring the mass loss rate. A fatigue test was conducted according to JTG D50-2017 "Design Specification for Asphalt Pavements of Highways", applying a 0.7 MPa pulse load at 15°C, and recording the number of failures. The results are shown in Table 1:

[0098] Table 1

[0099]

[0100]

[0101] As can be seen from Table 1, the raw materials in the embodiments of the present invention work together to effectively improve the mechanical properties and durability of the highway subgrade material. In particular, the electrolytic manganese slag and the microbial system in the present invention have a significant synergistic effect, which can improve the compressive strength and shrinkage rate of the material, greatly delay the initial cracking time of the material, and reduce the mass loss rate of the material during freeze-thaw cycles.

[0102] The above are merely preferred embodiments of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A crack-resistant and durable highway subgrade material, characterized in that: The composition comprises the following raw materials in parts by weight: 10-15 parts of steel slag, 20-30 parts of fly ash, 15-20 parts of electrolytic manganese slag, 3-5 parts of modified rubber particles, 1-2 parts of nano-SiO2, 5-20 parts of reinforcing fiber, and 0.2-1.5 parts of admixture.

2. The crack-resistant and durable highway subgrade material according to claim 1, characterized in that: The reinforcing fibers are obtained by mixing basalt fibers, straw fibers and alloy fibers in a mass ratio of 3:2:

1.

3. The crack-resistant and durable highway subgrade material according to claim 2, characterized in that: The alloy fiber is one or more of steel fiber, titanium alloy fiber and memory alloy fiber.

4. The crack-resistant and durable highway subgrade material according to claim 1, characterized in that: The admixtures include a microbial system and a functional additive.

5. The crack-resistant and durable highway subgrade material according to claim 4, characterized in that: The microbial system includes Bacillus, Pseudomonas and calcium lactate; and / or, The functional additives include retarders and shrinkage reducers.

6. The crack-resistant and durable highway subgrade material according to claim 1, characterized in that: The modified rubber particles are obtained by crushing waste tires and then treating them with a silane coupling agent.

7. The method for preparing the crack-resistant and durable highway subgrade material according to any one of claims 1 to 6, characterized in that: The following steps are involved: The steel slag, fly ash and electrolytic manganese slag are pretreated and then mixed with nano-SiO2 to obtain a dry mix; water is added to the dry mix to obtain a slurry, reinforcing fibers and modified rubber particles are added and mixed evenly, and then an admixture is added. After stirring evenly, the mixture is spread, vibrated and cured to obtain the crack-resistant and durable highway subgrade material.

8. The method for preparing the crack-resistant and durable highway subgrade material according to claim 7, characterized in that: The water is added at a water-to-binder ratio of 0.3-0.

45.

9. The method for preparing the crack-resistant and durable highway subgrade material according to claim 7, characterized in that: The pretreatment is as follows: crushing the steel slag, fly ash and electrolytic manganese slag, screening out impurities, and then drying them to complete the pretreatment.

10. The method for preparing the crack-resistant and durable highway subgrade material according to claim 7, characterized in that: The maintenance includes initial maintenance and long-term maintenance; Wherein, the initial maintenance includes the following steps: Under the conditions of 18-25℃ and humidity ≥90%, cover with wet cloth and maintain for 48 hours, then remove the film and spray water to keep it moist.

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