Roadbed water-stable material prepared from coal gangue and building slag synergistically and preparation method of roadbed water-stable material

Abstract

The invention relates to the technical field of road building materials, in particular to a roadbed water-stable material prepared by synergism of coal gangue and building slag and a preparation method of the roadbed water-stable material. The roadbed water-stable material comprises the following components: coal gangue fine aggregate with the mass ratio of less than or equal to 80% and the particle size of less than or equal to 2.36 mm; the mass ratio of the building slag coarse aggregate is larger than or equal to 20%, and the building slag coarse aggregate is continuously graded by 2.36-31.5 mm; based on the mass mcg of a mixture prepared from the coal gangue fine aggregate and the building slag coarse aggregate, the concrete also comprises 5-6% mcg of cement; a coupling agent with a mass of 0.15%.-2%. Mcg; the mass of water is (1.05-1.10) mcg * (omega o + 1%), and omega o is the original water content of the mixture. The coal gangue is crushed and screened to obtain the coal gangue superfine aggregate, the construction slag coarse aggregate is mixed, the compressive strength of the mixed material can be properly improved, the water absorption rate of the coal gangue is reduced by adding the coal gangue coupling agent, and synergistic improvement of strength and stability is achieved.

Description

Technical Field

[0001] This invention relates to the fields of comprehensive utilization of solid waste and road construction materials, specifically to a roadbed water-stabilized material prepared by co-processing coal gangue and construction slag, and its preparation method. Background Technology

[0002] Coal gangue is a solid waste generated during coal production. my country produces nearly 400 million tons of coal gangue annually, with a cumulative stockpile exceeding 3 billion tons, making it the largest industrial solid waste discharge in my country. Coal gangue has a complex composition, being an aggregate of various sedimentary rocks. Its main chemical components include alumina, silicon dioxide, iron oxide, calcium oxide, and magnesium oxide, as well as certain amounts of hydrocarbon combustibles. Coal gangue with a certain calorific value can be used as fuel, while gangue with a lower calorific value can be used as building material. However, coal gangue is a soft rock, mostly needle-like and flaky, and its porosity leads to strong water absorption, poor water stability, and lack of frost resistance. Directly using it as building material results in weak load-bearing capacity, affecting the comprehensive utilization of coal gangue and failing to meet the standards for roadbed construction.

[0003] In existing technologies, the recycling of coal gangue, a solid waste, is achieved through coal gangue calcination ceramsite technology. Because the chemical composition of coal gangue is highly compatible with the "silica-alumina raw materials" required for ceramsite production, the ceramsite produced from coal gangue through calcination can achieve a compressive strength of over 3 MPa, meeting the performance requirements of roadbed materials.

[0004] The key technology for calcined coal gangue ceramsite mainly consists of three parts: preheating, calcination, and cooling. After drying, the coal gangue particles enter the calcination kiln and are preheated at 200-600℃ to further remove internal moisture and initially decompose organic matter. The temperature is then raised to 1000-1200℃ (the critical temperature range), where the organic matter is fully combusted, producing gases such as CO2 and H2O, forming numerous bubbles inside the particles. Simultaneously, silicon and aluminum oxides melt and sinter, fixing the bubbles and forming a "porous skeleton structure." The calcined ceramsite is then slowly cooled (to avoid rapid cooling and cracking), ultimately forming a lightweight, high-strength finished product. The main problems are: first, the system is complex and requires significant investment, necessitating the construction of new preheating, calcination, and cooling equipment; second, the calcination process consumes fossil fuels, increasing carbon dioxide and pollutant emissions; and third, the high investment and energy consumption result in higher production costs than traditional sand and gravel aggregates.

[0005] This invention synergistically manages coal gangue and construction waste, giving full play to the characteristics of each material to produce roadbed water-stabilized material, providing a new path for the comprehensive utilization of solid waste: first, it can utilize existing commercial concrete plant personnel and equipment without additional investment; second, there is no additional energy consumption in the process; and third, the production cost is lower than that of traditional sand and gravel aggregates. Summary of the Invention

[0006] To overcome the shortcomings of the existing technology, the present invention aims to provide a method for preparing roadbed water-stabilized materials using coal gangue and construction slag in synergistic processing. Coal gangue, with its high organic matter content, low strength, and high water absorption, suffers from low strength and poor water stability when used directly as roadbed material. The method addresses these issues by: 1) crushing and screening the coal gangue to obtain ultrafine aggregate (within 2.36mm), and then mixing it with a certain proportion of high-strength coarse aggregate from construction slag, which can moderately improve the compressive strength of the mixed material; and 2) adding a coupling agent (0.15‰~2‰m). cg This material reduces the water absorption rate of coal gangue and improves its water and freeze resistance. It is a nanocomposite organic polymer material whose slightly yellow fluid form and water-soluble properties allow it to fully contact and interact with coal gangue particles, significantly enhancing the engineering performance of coal gangue through multiple mechanisms.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] The first aspect of this invention provides a roadbed water-stabilized material prepared by co-processing coal gangue and construction slag, comprising:

[0009] Coal gangue fine aggregate: ≤80% by mass, and the particle size of the coal gangue fine aggregate is ≤2.36mm;

[0010] Construction slag coarse aggregate: ≥20% by mass, wherein the construction slag coarse aggregate is 2.36-31.5mm continuous gradation and has been treated to remove impurities;

[0011] The mass percentage of the fine aggregate from coal gangue and the coarse aggregate from construction slag is 100%, and the mass m of the mixture prepared with the fine aggregate from coal gangue and the coarse aggregate from construction slag is... cg Based on this, it also includes:

[0012] Cement: 5%-6% by weight cg ;

[0013] Coupling agent: 0.15‰-2‰ by mass cg The coupling agent is a fluid-form nanocomposite organic polymer material that is water-soluble. It is a coal gangue coupling agent, model GS-1, provided by Zhongchuang Green Materials (Xi'an) Environmental Protection Technology Co., Ltd. This material contains nano-metal components and significantly improves the engineering performance of coal gangue through multiple mechanisms. It also polymerizes a variety of functional additives, such as binders, dispersants, and penetrants, which can significantly improve the strength and durability of the material.

[0014] The organic components in the coupling agent significantly improve the overall performance of the material by forming a strong binding layer and an oily layer. Sulfonated oil, a key component in the coupling agent, possesses a unique hydrophilic and hydrophobic duality in its molecular structure, consisting of a "hydrophilic head" of the organic compound sulfonic acid (RSO3H) and a "hydrophobic tail" composed of hydrocarbon atoms. When this structure diffuses in water, the hydrophilic head dissociates to generate sulfate ions, which form chemical chains with cations adsorbed on the particle surface. Simultaneously, an oily layer forms around the particles, hindering water penetration and imparting hydrophobic properties to the material.

[0015] In terms of the filling effect, the coupling agent reduces the thickness of the bound water layer, turning loose particles into a tightly aggregated structure, while the released free water participates in the hydration reaction of cement and other binders.

[0016] Water: mass (1.05~1.10)m cg ×(ω o +1%), ω o This represents the initial moisture content of the mixture.

[0017] The performance of the above-mentioned roadbed water-stabilized materials meets the following requirements: unconfined compressive strength of 5.0 MPa after 28-day freeze-thaw test, water stability coefficient ≥80%, freeze-thaw resistance index ≥95%, and freeze-thaw mass loss ≤5%.

[0018] A second aspect of the present invention provides a method for preparing the above-mentioned roadbed water-stabilized material by synergistic use of coal gangue and construction slag, comprising the following steps;

[0019] S1: Preparation of fine aggregate from coal gangue

[0020] Select coal gangue with poor engineering performance. The selected coal gangue is crushed by coarse crushing and fine crushing. A set of square hole screens is used to screen the coal gangue to obtain particles within 2.36mm as fine aggregate of coal gangue. Oversized particles that do not meet the requirements are returned to the crushing device for further crushing.

[0021] S2: Preparation of coarse aggregate for construction waste

[0022] Select the coarse aggregate of construction slag after crushing and impurity removal, and screen it. Take the continuous graded particles with a particle size within 2.36-31.5mm as the coarse aggregate of construction slag, and return the oversized particles to the crushing.

[0023] S3: Determine the optimal proportions of the mixture.

[0024] Coal gangue fine aggregate and construction slag coarse aggregate were mixed in different proportions to obtain a mixture. To ensure the required compaction and density after mixing and paving, a compaction test was conducted on the mixed raw materials to obtain the maximum dry density ρ. m Optimal moisture content ω m (%) and original moisture content ω oThe mixture is obtained;

[0025] Furthermore, repeating S1-S3, the optimal mix ratio of fine coal gangue aggregate with the highest maximum dry density and the lowest optimal moisture content to coarse construction slag aggregate is selected as the optimal mix ratio, wherein: fine coal gangue aggregate accounts for ≤80% of the total mass of the mixture, and coarse construction slag aggregate accounts for ≥20%.

[0026] S4: Preparation of water-stabilized materials

[0027] Select mass m according to the optimal ratio cg The mixture, 5% to 6% m cg Mix the cement dry until uniform, then add 0.15‰-2‰ m cg The coupling agent and a certain amount of water are mixed evenly to complete the preparation.

[0028] Furthermore, in S1, the coal gangue is crushed by sequential coarse crushing and fine crushing. The screening process is carried out using a square hole screen with a aperture of 2.36 mm, and particles with a particle size ≤ 2.36 mm are used as fine aggregate for coal gangue.

[0029] Furthermore, in S2, the construction slag screening process uses square-hole sieves with apertures of 2.36mm, 4.75mm, and 31.5mm to take coarse construction slag particles with a particle size of 2.36-31.5mm as coarse aggregate.

[0030] Furthermore, the cement in S4 is PO425 ordinary Portland cement.

[0031] Furthermore, in S4, the mass m of the tap water w = (1.05~1.10)m cg ×(ω o (+1%), based on the optimum moisture content of the aforementioned mixture compaction test, configure the amount of water to be added, and add 0.15‰~2‰m to the water. cg The coupling agent is used to bring the water-stabilized material to its optimal state of maximum dry density, ensuring the compaction and hydration reaction of the water-stabilized material. After stirring evenly, the aqueous solution is added to the solid mixture, and stirring is continued for 120-180 seconds to complete the preparation.

[0032] Furthermore, in S4, mixing is carried out in a mixer, with a dry mixing time of 100-120s and a wet mixing time of 120-180s. When using a dual-shaft motor with a reducer, the dry mixing speed is 20-50r / min, and the wet mixing speed is 35r / min. The main unit model is JS2000 or JS3000.

[0033] This invention fully utilizes the material properties of coal gangue and construction slag through appropriate raw material ratios, thereby improving the strength and frost resistance of water-stabilized materials. The roadbed water-stabilized materials are used for the base and subbase layers of roads of grade II and below.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] (1) Expanded the application scope of coal gangue

[0036] Coal gangue is soft, and after crushing, it produces a large amount of fine powder particles. These fine particles are mainly used for landfill and are difficult to reuse. This invention uses fine coal gangue particles as the main component and screened construction slag as coarse aggregate. After reasonable gradation with the fine coal gangue aggregate, the prepared roadbed water-stabilized material has the advantages of high strength, good water stability, and good frost resistance. Based on actual application results, it can be used as a substitute for traditional sand and gravel water-stabilized materials, expanding the comprehensive utilization range of coal gangue.

[0037] (2) Reduce costs and improve efficiency

[0038] This invention discloses a method for preparing roadbed water-stabilized materials using coal gangue and construction slag in synergistic processes. Production can be carried out using existing equipment, requiring no additional equipment or personnel. Through multiple mechanisms, including the addition of a coupling agent to promote hydration reactions, ion exchange adsorption, synergistic filling-cementation, and the construction of hydrophobic microdomains, the potential activity of coal gangue is significantly stimulated. Simultaneously, the high strength of the coarse aggregate from the construction slag compensates for the mechanical defects caused by the needle-like and porous nature of the coal gangue, resulting in a new water-stabilized material with excellent compressive strength, water resistance, and freeze-thaw resistance, and long-term stability. Experimental results show that when the mass ratio of coal gangue to construction slag is 7:3, the cement content is 6%, and the coupling agent content is 0.015%, the 7-day unconfined compressive strength reaches 3.23 MPa, the water stability coefficient is 82.1%, and the strength loss rate after freeze-thaw cycles is <5%, meeting the national technical standards for secondary highway base courses. Field core drilling on a 250m pilot section verified 100% core sample integrity. The construction process is fully compatible with traditional water-stabilized materials, requiring no additional equipment investment.

[0039] (3) Improve strength and stability

[0040] The present invention achieves a synergistic improvement in strength and stability by effectively filling the pores of slag with fine coal gangue particles and by using a coupling agent to promote the formation of interfacial gel, resulting in a stable "skeleton-filling-cementing" structure. Attached Figure Description

[0041] Figure 1 This is a flowchart illustrating the road pilot-scale production process of the new roadbed water-stabilized material for this invention.

[0042] Figure 2 Data from coal gangue compaction tests;

[0043] Figure 3 Data from the slag compaction test. Detailed Implementation

[0044] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] I. Experimental Materials and Equipment

[0046] The main equipment used in the test included a Type 101 electric heating drying oven (temperature control accuracy ±5℃), a hammer crusher (crushing particle size can be controlled within 5mm), a multi-functional electric compactor (working voltage 220V), a 600kN universal press, a CF-B type constant temperature water bath (temperature control accuracy ±1℃), and a freeze-thaw test chamber (stable control at -18℃±1℃). All equipment met the requirements of GB / T 50123-2019 "Standard for Geotechnical Testing Methods" to ensure the accuracy and reliability of the test data.

[0047] II. Implementation Examples

[0048] Example 1: Basic Formulation Validation Experiment

[0049] 1. Preparation of experimental materials for roadbed water-stabilized materials

[0050] Coal gangue: sourced from Zhangye Hongneng Coal Industry Co., Ltd., Shandan County.

[0051] Construction waste: taken from Shandan County Shenghao Urban Renewal and Construction Co., Ltd.

[0052] Cement: PO425 ordinary Portland cement, conforming to GB 175-2007 "General Portland Cement" standard;

[0053] Coupling agent: Nanocomposite organic polymer material, using coal gangue-based coupling agent provided by Zhongchuang Green Materials (Xi'an) Environmental Protection Technology Co., Ltd., model GS-1.

[0054] Tap water: Sourced from Shandan County Water Supply Company;

[0055] 2. Preparation method

[0056] The method for preparing roadbed water-stabilized materials using the above-mentioned coal gangue and construction slag synergistically includes the following steps:

[0057] S1: Select coal gangue with poor engineering performance. The selected coal gangue is crushed by coarse and fine crushing. A set of square hole screens is used to screen the coal gangue to remove coarse particles and obtain fine coal gangue aggregate within 2.36mm. The coal gangue that does not meet the requirements is returned to the crushing device for further crushing.

[0058] S2: After crushing and removing impurities from the construction slag, it is screened to remove fine particles smaller than 2.36mm and coarse particles larger than 31.5mm. Continuous graded particles with a particle size of 2.36-31.5mm are taken as coarse aggregate for construction slag, and oversized particles are returned to crushing.

[0059] S3: Determine the optimal proportions of the mixture.

[0060] The above-mentioned coal gangue fine aggregate and slag coarse aggregate were mixed in different proportions to obtain mixtures. The maximum dry density ρ of each mixture was determined by compaction test. m Optimal moisture content ω m (%) and original moisture content ω o The optimal mix ratio is selected based on the highest dry density and lowest moisture content, wherein: fine aggregate of coal gangue accounts for ≤80% of the total mass of the mixture, and coarse aggregate of construction slag accounts for ≥20%.

[0061] S4: Preparation of water-stabilized materials

[0062] Select mass m according to the optimal ratio cg The mixture, 5% to 6% m cg Mix the cement dry until uniform, then add 0.15‰-2‰ m cg The coupling agent and a certain amount of water are mixed evenly to complete the preparation.

[0063] The roadbed water-stabilized material was tested according to the following different proportions. To investigate the effects of different proportions of coal gangue and slag, cement content, and coupling agent addition on material performance, tap water was omitted from the following proportions. The addition of tap water was based on (1.05~1.10)m cg ×(ω o Add +1% (ω) o This represents the initial moisture content of the mixture.

[0064] Specifically, the moisture content was determined using the drying method: a 50g sample was placed in an oven at 110℃ and dried to constant weight; the moisture content was determined by calculating the mass difference before and after drying. Simultaneously, the maximum dry density and optimum moisture content of coal gangue and slag were determined through heavy compaction tests. Figure 2 and 3 The results showed that the optimal moisture content of coal gangue was 7.7%, and the maximum dry density was 1.91 g / cm³. 3 The optimal moisture content of the construction waste is 11.5%, and the maximum dry density is 1.67 g / cm³. 3 This provides basic parameters for subsequent proportioning design.

[0065] (1) Ratio 1

[0066] PO425 cement: coupling agent: fine aggregate (coal gangue): coarse aggregate (coal gangue) = 0.06:0.00015:0.7:0.3.

[0067] (2) Ratio 2

[0068] PO425 cement: coupling agent: fine aggregate (coal gangue): coarse aggregate (construction slag) = 0.06: 0.00015: 0.8: 0.2.

[0069] (3) Ratio 3

[0070] PO425 cement: coupling agent: fine aggregate (coal gangue): coarse aggregate (construction slag) = 0.06: 0.00015: 0.7: 0.3.

[0071] (4) Ratio 4

[0072] PO425 cement: coupling agent: fine aggregate (coal gangue): coarse aggregate (construction slag) = 0.06:0.00015:0.6:0.4.

[0073] (5) Ratio 5

[0074] PO425 cement : fine aggregate (coal gangue) = 0.06 : 1

[0075] (6) Proportion 6

[0076] PO425 cement: coupling agent: fine aggregate (coal gangue) = 0.06:0.00015:1.

[0077] 3. Preparation of test specimens:

[0078] According to the above-mentioned mix proportions for roadbed water-stabilized materials, the materials are mixed according to the steps of the preparation method, and then... The molds are made in proportion to produce 6 pieces per set. The cylindrical specimens were placed in a constant temperature and humidity curing room for curing (temperature 20℃±2℃, relative humidity ≥95%).

[0079] III. Analysis of Experimental Results

[0080] 1. Strength test:

[0081] Six specimens were cured for 6 days and then pressure-tested after being saturated with water; another six specimens were cured for 7 days and then pressure-tested. Their unconfined compressive strength and water stability were tested (expressed as the ratio of the strength after 24 hours of water saturation to the strength in the dry state), and the pressure ratio of the two was the water stability coefficient.

[0082] Table 1. 7-day unconfined strength and water stability test data of roadbed water-stabilized materials with different mix proportions.

[0083] Proportion Mixing ratio 1 2 ratio 3 ratio 4 ratio 5 ratio 6 ratio Strength, MPa 2.04 2.8 3.23 3.03 1.43 1.98 Water stability, % 76％ 81％ 82％ 84％ 74％ 77％

[0084] Through synergistic proportion optimization experiments, it was found that when the ratio of coal gangue to construction slag was 7:3, the cement content was 6%, and the amount of coupling agent added was 0.015%, the performance of the specimen reached the optimal level.

[0085] To further verify the stability of the synergistic mix optimization test, repeated stability tests were conducted on specimens made of roadbed water-stabilized material with a mix ratio of coal gangue and construction slag of 7:3, a cement content of 6%, and a coupling agent content of 0.015%. The test results are shown in Table 2 below.

[0086] Table 2. Unconfined strength and water stability test data of 70% Shandan coal gangue + 30% slag with added coupling agent after 7 days.

[0087]

[0088] As shown in Table 2, the roadbed water-stabilized material specimens obtained by mix ratio 3 have an unconfined compressive strength of 3.23 MPa after 7 days and a coefficient of variation of 5.6%, indicating that the material has good performance stability; the water stability coefficient is 82.1%, which meets the engineering requirements for water stability.

[0089] 2. Freeze-thaw test

[0090] In addition, freeze-thaw tests were conducted on roadbed water-stabilized material specimens obtained from mix ratio 3. Five cycles were performed (one cycle consisted of freezing at -18℃ for 16 hours followed by thawing in 20℃ water for 8 hours). The frost resistance index was calculated by comparing the strength after freeze-thaw to the strength before freeze-thaw, thus comprehensively evaluating the material's durability. After a 28-day freeze-thaw test, the unconfined compressive strength of the new roadbed water-stabilized material was 5.0 MPa, the water stability coefficient was 89.2% (national standard ≥80%), the frost resistance index was 96.53% (national standard ≥80%), and the mass loss rate was only 0.8% (national standard freeze-thaw mass loss ≤5%). All indicators met the requirements of JTG / T F20-2015 "Technical Specifications for Construction of Highway Pavement Base Course".

[0091] 3. Road Trial

[0092] To verify the applicability of coal gangue disposal technology based on the synergistic treatment of coupling agent and construction slag in practical engineering, a pilot-scale test of a new roadbed water-stabilized material was conducted in Shandan County, Gansu Province on October 22, 2024. The pilot test section was a 250-meter section of municipal road in Shandan County, using the plant-mixing method. The process included surveying and setting out, plant mixing, transportation, paving of the mixture, compaction, and curing. (See attached document). Figure 1After the curing period, a comprehensive inspection was conducted on the test section according to JTG E60-2008 "Specifications for Field Testing of Highway Subgrade and Pavement". Visual inspection showed that the subgrade surface was smooth and flat, without cracks, dry patches, bulges, or other defects. The edges were straight and neat, indicating good overall forming quality. Core sampling yielded 10 core samples with a specification of Φ150mm×100mm. All core samples had an integrity of over 95%, with no delamination, discontinuity, or missing edges. The top surface of the core samples was dense and uniform around the perimeter, with a 100% pass rate. Strength test results showed that the average unconfined compressive strength of the core samples after 7 days was 3.18MPa, with a minimum of 2.95MPa, both meeting the strength requirements of a secondary highway base course. In the bearing capacity test, the subgrade resilient modulus reached 3200MPa, exceeding the design requirement of 2800MPa, indicating that the subgrade has good bearing capacity. On-site core sampling and testing showed that the roadbed surface was smooth, the core samples had high integrity, and the pass rate was 100%, verifying the applicability of the new roadbed water-stabilized material under traditional construction techniques. On August 25, 2025, a second on-site core sampling and monitoring showed that the core samples were intact, with a 100% pass rate. These pilot-scale test results fully demonstrate that this collaborative treatment technology is adaptable to traditional road construction techniques, requires no additional specialized equipment, and can be directly applied to the base construction of municipal roads and highways, providing reliable engineering practice evidence for the large-scale promotion of the technology.

[0093] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concepts, should be covered within the scope of protection of the present invention.

Claims

1. A roadbed water-stabilized material prepared by co-processing coal gangue and construction slag, characterized in that, include: Coal gangue fine aggregate: ≤80% by mass, and the particle size of the coal gangue fine aggregate is ≤2.36mm; Construction slag coarse aggregate: ≥20% by mass, wherein the construction slag coarse aggregate is 2.36-31.5mm continuous gradation and has been treated to remove impurities; The mass percentage of the fine aggregate from coal gangue and the coarse aggregate from construction slag is 100%, and the mass m of the mixture prepared with the fine aggregate from coal gangue and the coarse aggregate from construction slag is... cg Based on this, it also includes: Cement: 5%-6% by weight cg ; Coupling agent: 0.15‰-2‰ by mass cg The coupling agent is a slightly yellow, fluid-like nanocomposite organic polymer material that is water-soluble. Water: mass (1.05~1.10)m cg ×(ω o +1%), ω o This represents the initial moisture content of the mixture.

2. The roadbed water-stabilized material according to claim 1, characterized in that, The performance of the roadbed water-stabilized material meets the following requirements: unconfined compressive strength of 5.0 MPa after 28-day freeze-thaw test, water stability coefficient ≥80%, freeze resistance index ≥95%, and freeze-thaw mass loss ≤5%.

3. A method for preparing the roadbed water-stabilized material according to claim 1 or 2 by synergistic use of coal gangue and construction slag, characterized in that, Includes the following steps: S1: Preparation of fine aggregate from coal gangue After crushing, the coal gangue is screened to obtain particles with a diameter ≤2.36mm as fine aggregate, while oversized particles are returned to the crusher. S2: Preparation of coarse aggregate for construction waste Select the coarse aggregate of construction slag after crushing and impurity removal, and screen it. Take the continuously graded particles with a particle size of 2.36-31.5mm as the coarse aggregate of construction slag, and return the oversized particles to the crushing. S3: Determine the optimal proportions of the mixture. The fine aggregate of coal gangue and the coarse aggregate of slag were mixed in different proportions to obtain mixtures. The maximum dry density ρ of each mixture was determined by compaction test. m Optimal moisture content ω m (%) and original moisture content ω o The optimal mix ratio is selected based on the highest dry density and lowest moisture content, where: fine aggregate of coal gangue accounts for <80% of the total mass of the mixture, and coarse aggregate of construction slag accounts for >20%. S4: Preparation of water-stabilized materials Select mass m according to the optimal ratio cg The mixture, 5% to 6% m cg Mix the cement dry until uniform, then add 0.15‰-2‰ m cg The coupling agent and a certain amount of water are mixed evenly to complete the preparation.

4. The method according to claim 3, characterized in that, In S1, the coal gangue is crushed by coarse crushing and fine crushing in sequence. The screening process is carried out by a square hole screen with a aperture of 2.36mm. Particles with a particle size ≤2.36mm are used as fine aggregate for coal gangue.

5. The method according to claim 3, characterized in that, In S2, the construction slag screening process uses square-hole sieves with apertures of 2.36mm, 4.75mm, and 31.5mm to take coarse construction slag particles with a particle size of 2.36-31.5mm as coarse aggregate.

6. The method according to claim 3, characterized in that, The cement in S4 is PO425 ordinary Portland cement.

7. The method according to claim 3, characterized in that, In S4, the mass of water added is (1.05~1.10)m. cg ×(ω o +1%), ω o This represents the initial moisture content of the mixture.

8. The method according to claim 3, characterized in that, In S4, mixing is carried out in a mixer, with a dry mixing time of 100-120s and a wet mixing time of 120-180s.

9. The application of the roadbed water-stabilized material according to claim 1 or 2 in the base course and subbase course of roads of grade II and below.

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