Solid waste-based pavement surface layer material, method for confirming proportioning of solid waste-based pavement surface layer material, and application thereof

Abstract

This invention belongs to the technical field of pavement surface materials, specifically a solid waste-based pavement surface material and its mix design method and application. Based on the porous characteristics of steel slag, this invention proposes a method for calculating the specific surface area of ​​steel slag and the amount of asphalt coating. It employs the principle of volumetric design and controls the blending ratio of old asphalt mixtures, copper tailings, and steel slag using key sieve apertures. This avoids interference from fillers on the skeleton and effectively controls the total amount of asphalt used, thereby optimizing the skeleton filling structure design and the precise control system of the asphalt-aggregate ratio. This results in the preparation of solid waste-based asphalt mixtures with excellent performance, strong stability, and outstanding economic benefits.

Description

Technical Field

[0001] This invention belongs to the field of pavement surface material technology, and particularly relates to a solid waste-based pavement surface material, its proportioning confirmation method, and its application. Background Technology

[0002] Steel slag and copper tailings are typical general industrial solid wastes generated during the metallurgical and mining industries. They easily cause a series of ecological and environmental problems such as soil pollution, water loss, and dust pollution, placing immense pressure on solid waste disposal. Meanwhile, the existing highway network continues to expand, and a large number of existing roads are entering a phase of routine maintenance. Each year, maintenance operations generate a massive amount of waste asphalt mixture. Directly discarding such waste materials would not only waste resources but also exacerbate the burden of solid waste disposal.

[0003] In the field of highway infrastructure construction, the demand for natural sand and gravel aggregates is enormous. However, long-term large-scale quarrying for road construction aggregates damages mountain vegetation, causes soil erosion, and exacerbates ecological damage. Furthermore, existing high-quality natural road construction sand and gravel resources are increasingly depleted, leading to a growing imbalance between supply and demand for natural aggregates, which severely restricts the high-quality development of highway construction and maintenance. Therefore, using industrial solid waste and discarded road materials to prepare recycled road construction materials to replace traditional natural sand and gravel aggregates has become a core development direction that balances the resource utilization of solid waste, ecological environmental protection, and cost reduction and efficiency improvement in highway construction.

[0004] Existing research indicates that steel slag, copper tailings, and waste asphalt mixtures all possess excellent recycling value and are suitable for asphalt pavement material preparation scenarios. Among them, steel slag, with its geometric morphology and mechanical properties highly similar to traditional rolled aggregate, can completely replace natural stone as coarse aggregate in asphalt mixtures. Compared to conventional crushed stone, steel slag has a porous surface, excellent adsorption performance, a large internal friction angle, and strong interlocking effect, significantly improving the structural stability and mechanical properties of asphalt mixtures. Copper tailings, with their uniform particle size and fine particles, can be used as a high-quality filler in asphalt mixture proportioning systems. The residual asphalt and original aggregates in waste asphalt mixtures retain high usability, and recycling them can significantly reduce raw material consumption. Currently, the industry is gradually conducting research on the synergistic application of these three types of solid waste materials in highway asphalt pavement construction. The conventional technical approach involves using steel slag to construct the asphalt mixture skeleton interlocking structure, combined with copper tailings and waste asphalt mixtures to fill the skeleton voids, achieving synergistic resource utilization of multiple solid wastes and alleviating the dual pressures of solid waste disposal and natural aggregate shortages.

[0005] Currently, asphalt mixture mix design is mainly based on the "Technical Specification for Construction of Highway Asphalt Pavement" (JTG F40-2017). The conventional mix design process involves first determining the blending ratio of each grade of aggregate, and then estimating the asphalt-aggregate ratio based on the aggregate's composite specific surface area and the preset uniform asphalt film thickness, thus completing the basic mix design of the asphalt mixture. However, the existing technology and specification system have significant defects and technical blind spots in the design of multi-solid-waste composite asphalt mixtures, and cannot adapt to the design requirements of the porous characteristics of steel slag and the synergistic blending of multiple solid wastes.

[0006] On the one hand, the formula for calculating the specific surface area of ​​aggregates in the current specifications is only for the design of conventional dense crushed stone aggregates, and does not take into account the porous structure of steel slag with abundant open pores on its surface, making it impossible to accurately calculate the actual effective specific surface area of ​​steel slag. On the other hand, the strong adsorption properties of steel slag cause some asphalt to penetrate into its internal pores, rather than just uniformly coating the aggregate surface. Using the traditional specification method to estimate the asphalt-aggregate ratio will significantly underestimate the actual amount of asphalt used, resulting in a large error in the calculation of the asphalt-aggregate ratio, which directly affects the bonding performance, waterproofing performance, and durability performance of asphalt mixtures.

[0007] On the other hand, existing steel slag-based skeleton interlocking structure designs have significant technical shortcomings. Current designs rely solely on the mechanical advantages of steel slag's high interlocking and high internal friction angle to construct the skeleton structure, simply using copper tailings and waste asphalt mixtures for void filling. They fail to systematically consider the negative impact of filler characteristics on the overall skeleton structure's stability and interlocking effect. Furthermore, existing mix design does not optimize the asphalt-aggregate ratio control logic for multi-solid-waste composite systems, and it does not accurately adjust the overall asphalt content based on the residual asphalt in waste asphalt. This easily leads to an excessively high asphalt-aggregate ratio in the mixture, significantly increasing construction costs and easily causing early-stage defects such as bleeding, rutting, and sulking in asphalt pavements, severely reducing the service life and performance of asphalt pavements. Summary of the Invention

[0008] To overcome the shortcomings of the prior art, this invention provides a solid waste-based pavement surface material, its proportioning confirmation method, and its application. This invention precisely adapts to the characteristics of porous steel slag materials, optimizes the skeleton filling structure design and the precise control system of the asphalt-aggregate ratio, and prepares a solid waste-based pavement surface material with excellent performance, strong stability, and outstanding economic benefits.

[0009] To achieve one of the above objectives, the present invention adopts the following technical solution: A method for confirming the mix proportions of solid waste-based road surface materials includes the following steps: S1. The surface material of the solid waste base road includes copper tailings, steel slag, old asphalt mixture, and new asphalt. Among them, steel slag is divided into fine aggregate steel slag (steel slag used as fine aggregate) and coarse aggregate steel slag (steel slag used as coarse aggregate) according to particle size. The copper tailings and steel slag of each particle size are screened to determine the gradation composition of steel slag and copper tailings of each particle size. Extraction tests are conducted on the old asphalt mixture to determine its gradation composition and asphalt content. S2. According to the gradation range requirements of each sieve size above 2.36mm specified in the standard, design the gradation of the solid waste base pavement surface material and determine the blending ratio of steel slag. S3. Take steel slag samples of each particle size with an average weight of ≥500g as steel slag samples. Calculate the specific surface area of ​​steel slag samples of each particle size based on the thickness of the surface water film and the volume of adsorbed water. S4. According to the theory of asphalt film formation, asphalt can coat steel slag at the optimal asphalt film thickness. The amount of asphalt coated with steel slag is calculated by combining the specific surface area of ​​steel slag and the thickness of asphalt film. Marshall specimens are prepared according to the amount of coarse aggregate steel slag and asphalt, and the porosity of the specimens is calculated. S5. According to the volumetric filling theory, some of the newly added asphalt, old asphalt mixture, copper tailings, and fine aggregate steel slag are filled in the voids formed by the newly added asphalt coating the coarse aggregate steel slag. The remaining void ratio is the design void ratio of the solid waste base pavement surface material. The coarse aggregate steel slag constitutes the basic skeleton of the surface material. After the old asphalt mixture, copper tailings, and fine aggregate steel slag are filled, they do not expand the skeleton structure. It is necessary to control the content of all materials below 2.36mm. The smaller the particle size, the larger the specific surface area, and the more asphalt is required to coat it. To accurately control the amount of asphalt, it is necessary to control the content of all materials below 0.075mm. Based on the gradation requirements of 2.36mm and 0.075mm sieve passing rates, calculate the amount of old asphalt mixture, copper tailings, and fine aggregate steel slag. S6. Asphalt adheres to the surface of steel slag, copper tailings, and old asphalt mixture to form an asphalt film. Steel slag has many pores, and asphalt adheres to the surface of the steel slag to form an asphalt film. Some asphalt enters the pores inside the steel slag. Based on the specific surface area of ​​steel slag, the specific surface area of ​​copper tailings, the specific surface area of ​​aggregates in the old asphalt mixture, and the optimal asphalt film thickness, and combined with the amount of asphalt in the old asphalt mixture, the amount of new asphalt is calculated.

[0010] Preferably, in step S3, the steel slag samples of each particle size are soaked in water for 24 hours, filtered, poured into an iron cup, with absorbent paper at the bottom and filter paper at the top, and centrifuged for 2-3 minutes. The mass of the steel slag sample is then measured. After drying, the mass is measured again, and the specific surface area of ​​the steel slag samples of each particle size is calculated according to the following formula: ; ; In the formula: —The mass of the steel slag sample after immersion in water and centrifugation to remove pore water, in grams; —The mass of the steel slag sample after immersion in water and centrifugation, in grams; —Volume water absorption rate of steel slag sample, % ρ s —Density of water, g / cm³ 3 ; ρ k —Density of the steel slag sample, g / cm³ 3 ; —The mass of the steel slag sample after the surface water has been absorbed, in grams; SA—Specific surface area of ​​steel slag sample, m² 2 / kg; μ s —Water film thickness, in μm; —The mass of the steel slag sample taken, in grams.

[0011] Preferably, the porosity of the specimen is calculated according to the following formula: ; ; ; In the formula: —When steel slag is coated with asphalt at the optimal asphalt film thickness, the percentage of asphalt is %. μ—the average thickness of the bitumen film formed by bitumen coating on the surface of steel slag and copper tailings, in μm; ρ a —Density of asphalt, g / cm³ 3 ; SA1—Specific surface area of ​​steel slag with a particle size of 5-10 mm in coarse aggregate steel slag, in m² 2 / kg; —The proportion of steel slag with a particle size of 5-10mm in the coarse aggregate steel slag, % SA2—Specific surface area of ​​steel slag with a particle size of 10-15mm in coarse aggregate steel slag, in m² 2 / kg; 2—Volume water absorption rate of steel slag with a particle size of 10-15mm in coarse aggregate steel slag, % ρ2—Density of steel slag with a particle size of 10–15 mm in coarse aggregate steel slag, in g / cm³ 3 ; ρ1—Density of steel slag with a particle size of 5–10 mm in coarse aggregate steel slag, g / cm³ 3 ; 1—Volume water absorption rate of steel slag with a particle size of 5-10 mm in coarse aggregate steel slag, % ρ h —The composite density of coarse aggregate steel slag asphalt mixture, g / cm³ 3 ; VC—Porosity of coarse aggregate steel slag asphalt mixture, % ρ c —Bulk density of coarse aggregate steel slag asphalt mixture, g / cm³ 3 .

[0012] Preferably, the amounts of steel slag, old asphalt mixture, and copper tailings are calculated according to the following formula: ; + + + =100; In the formula: —The percentage of copper tailings in solid waste-based road surface materials, % ρ w —Density of copper tailings, g / cm³ 3 ; —The proportion of fine aggregate steel slag in solid waste-based pavement surface materials, % ρ g —Density of fine aggregate steel slag, g / cm³ 3 ; —The percentage of used asphalt mixture in solid waste-based pavement surface materials, % ρ j —Density of old asphalt mixture, g / cm³ 3 ; —The percentage of newly added asphalt in solid waste-based road surface materials, % —When steel slag is coated with asphalt at the optimal asphalt film thickness, the percentage of asphalt is %. —The proportion of coarse aggregate steel slag in solid waste-based pavement surface materials, % ρ a —Density of freshly added asphalt, g / cm³ 3 ; ρ d —Compacted density of synthetic coarse aggregate steel slag asphalt mixture, g / cm³ 3 ; VC—Porosity of coarse aggregate steel slag asphalt mixture, % VV—Design porosity of solid waste-based road surface material, %, ranging from 3% to 5%.

[0013] Preferably, the proportions of old asphalt mixture, copper tailings, fine aggregate, and steel slag are calculated according to the following formula: ; ; In the formula: —Copper tailings throughput of 0.075mm; —The aggregate passing rate of the extracted old asphalt mixture is 0.075mm; —Fine aggregate steel slag passing rate of 2.36mm; —The aggregate passing rate of the extracted old asphalt mixture is 2.36mm; —Graining requirement is a passing rate of 0.075mm, taken as 8-12; —Grain requirement is a 2.36mm passing rate, taken as 18-22; — Copper tailings throughput of 2.36 mm.

[0014] Preferably, the proportion of newly added asphalt is calculated according to the following formula; ; + + ; In the formula: —The average thickness of the asphalt film on the aggregate surface in the old asphalt mixture, in μm; —Percentage of asphalt in old asphalt mixture, % —Density of the old asphalt mixture after extraction, in g / cm³ 3 ; SA j —Specific surface area of ​​aggregates in old asphalt mixture, m² 2 / kg; —The percentage of newly added asphalt in solid waste-based pavement surface materials, % —When steel slag is coated with asphalt at the optimal asphalt film thickness, the percentage of asphalt is %. —The proportion of coarse aggregate steel slag in solid waste-based pavement surface materials, % —The percentage of copper tailings in solid waste-based road surface materials, % —The average thickness of the asphalt film formed by the asphalt coating on the surface of steel slag and copper tailings, in μm; ρ a —Density of freshly added asphalt, g / cm³ 3 ; SA w —Specific surface area of ​​copper tailings, m 2 / kg; —The percentage of used asphalt mixture in solid waste-based pavement surface materials, % SA3—Specific surface area of ​​fine aggregate steel slag, m² 2 / kg; —The proportion of fine aggregate steel slag in solid waste-based pavement surface materials, % —Volume water absorption rate of fine aggregate steel slag, % ρ g —Density of fine aggregate steel slag, g / cm³ 3 .

[0015] Preferably, the specific surface area of ​​the old asphalt mixture and copper tailings is calculated according to the following formula: ; ; (The coefficients on the right side of this formula all include the unit m) 2 / kg); In the formula: —Average particle size of copper tailings, mm; —Sieve aperture size, mm; —The size of the sieve aperture of the previous sieve in the i-th sieve, in mm; —Copper tailings in the sieve The sieve residue, % SA w —Specific surface area of ​​copper tailings, m 2 / kg; ρ w —Density of copper tailings, g / cm³ 3 ; SA j —Specific surface area of ​​aggregates in old asphalt mixture, m² 2 / kg; a—Passing rate of aggregates in old asphalt mixture through a 4.75mm sieve; b—Passing rate of aggregates in old asphalt mixture through a 2.36 mm sieve; c—Passing rate of aggregates in old asphalt mixture through a 1.18 mm sieve; d—Passage of aggregates in old asphalt mixture through a 0.6 mm sieve; e—The passing rate of aggregates in old asphalt mixtures through a 0.3mm sieve; f—the passing rate of aggregates in old asphalt mixtures through a 0.15mm sieve; g—The passing rate of aggregates in old asphalt mixtures through a 0.075 mm sieve.

[0016] Preferably, the newly added asphalt is SBS modified asphalt; the moisture content of the old asphalt mixture is ≤2.0%, and the old asphalt in the old asphalt mixture is old SBS modified asphalt; The water film thickness is 7–10 μm, and the optimal asphalt film thickness is 8–12 μm.

[0017] Preferably, the copper tailings have a particle size ≤ 0.6 mm and a copper tailings 0.075 mm throughput ≥ 60%; The fine aggregate steel slag has a particle size of 3-5 mm, the coarse aggregate steel slag has a particle size of 5-10 mm and a particle size of 10-15 mm; the particle size of the old asphalt mixture is 0-5 mm.

[0018] To achieve the second objective mentioned above, the present invention provides a solid waste-based pavement surface material prepared by a proportioning confirmation method.

[0019] To achieve the third objective mentioned above, the present invention provides an application of a solid waste-based road surface material, comprising the following steps: (1) Based on the proportions of each grade of material determined by the mix design, the mixing plant prepares the solid waste base pavement surface material; (2) Transport road surface materials based on multi-element solid waste to the site for paving and compaction; (3) After compaction is completed, a quality inspection shall be carried out in accordance with the relevant specifications.

[0020] The advantages of this invention are: (1) This invention precisely adapts to the characteristics of porous steel slag materials, optimizes the skeleton filling structure design and the precise control system of oil-stone ratio, and prepares solid waste-based asphalt mixture with excellent performance, strong stability and outstanding economic benefits, thus solving many defects of the existing technology.

[0021] (2) Based on the porous characteristics of steel slag, this invention proposes a method for calculating the specific surface area of ​​steel slag and the amount of asphalt coating. It adopts the principle of volume design and controls the proportion of old asphalt mixture and copper tailings and steel slag with small particle size by using key sieve holes. This avoids the interference of filler on the skeleton and effectively controls the total amount of asphalt. In this way, the skeleton filling structure design and the asphalt-aggregate ratio control system are optimized, and solid waste-based asphalt mixture with excellent performance, strong stability and outstanding economic benefits is prepared.

[0022] (3) This invention takes volume design theory as its core and uses coarse-grained steel slag as the main skeleton support structure. Copper tailings, waste asphalt mixture, fine-grained steel slag and asphalt are precisely filled into the voids of the steel slag skeleton to form a dense composite structure with excellent integrity. At the same time, by precisely controlling the volume mixing parameters of each component material and strictly controlling the passing rate of key sieves of the mixture, the interference and damage of the filling material to the steel slag skeleton interlocking structure are effectively avoided. The mechanical advantages of the high internal friction angle and strong interlocking effect of steel slag are preserved to the greatest extent, ensuring that the pavement surface material has excellent structural stability, compressive strength and deformation resistance.

[0023] (4) This invention proposes a specific surface area testing method adapted to porous steel slag, which can accurately calculate the actual effective specific surface area of ​​steel slag. At the same time, it fully considers the porous and strongly adsorbent material characteristics of steel slag, takes into account both the amount of film-forming asphalt uniformly coated on the surface of steel slag and the amount of adsorbed asphalt penetrating into the pores inside the steel slag, and establishes an accurate calculation model for asphalt dosage, so as to realize the scientific and accurate determination of the asphalt-aggregate ratio of the mixture, and reduce the blindness of the asphalt-aggregate ratio prediction and the dependence on experience.

[0024] (5) This invention uses key sieve holes to precisely control the overall amount of asphalt, effectively avoiding the blind determination of the mixing ratio of copper tailings and old asphalt mixture, which leads to an excessively high asphalt-aggregate ratio. It combines the characteristics of waste asphalt with residual asphalt to precisely control the overall amount of asphalt, maximizing the role of old asphalt and newly added asphalt, ensuring that the asphalt mixture has good performance, and effectively reducing material costs.

[0025] (6) The preparation method of the present invention is adapted to the standardization of solid waste pavement surface material for the synergistic application of steel slag, copper tailings and waste asphalt mixture. It has a targeted accurate calculation model for the specific surface area of ​​steel slag and an accurate calculation method for the amount of porous aggregate asphalt. It also takes into account the structural stability, service performance and economic cost of the mixture, and realizes the high-performance, controllable and low-cost preparation of multi-solid waste asphalt mixture. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0027] Example 1 Sampling was performed on copper tailings and steel slag. The copper tailings were then dried, and the steel slag with a particle size of 3-5 mm, 5-10 mm, and 10-15 mm, as well as the dried copper tailings, were screened. The results are shown in Table 1 below. Table 1 Screening Results

[0028] According to the "Technical Specifications for Construction of Asphalt Pavement on Highways", the gradation results of steel slag with particle sizes of 5-10mm and 10-15mm are shown in Table 2 below: Table 2 Blending Ratio

[0029] The volumetric water absorption rate and density of steel slag and the density of copper tailings were tested, and the results are shown in Table 3 below: Table 3 Raw material test results

[0030] Extraction was performed on old asphalt mixtures with a particle size of 0-5 mm. The raw material test results are shown in Table 4-5 below: Table 4. Sieving results of old asphalt mixture after extraction

[0031] Table 5 Test Results of Raw Materials for Old Asphalt Mixture

[0032] Take at least 500g of each of the following steel slag samples: 3-5mm, 5-10mm, and 10-15mm. Soak each sample in water for 24 hours, then filter. Pour the samples into iron cups, placing absorbent paper at the bottom and filter paper at the top. Centrifuge the cups for 2-3 minutes and weigh the samples. After drying, weigh the samples again. Calculate the specific surface area of ​​the samples based on the thickness of the water film on the sample surface and the volume of adsorbed water using the following formula. The water film thickness is taken as 8µm, and the water density as 1g / cm³. 3 : ; ; Table 6 Specific surface area of ​​steel slag samples

[0033] According to the theory of asphalt film formation, asphalt can coat steel slag at the optimal asphalt film thickness. The amount of asphalt coated with steel slag is calculated by combining the specific surface area of ​​the steel slag and the asphalt film thickness. Marshall specimens are prepared based on steel slag with a particle size of 5–10 mm and 10–15 mm, as well as the amount of asphalt used and an asphalt film thickness of 10 μm. The porosity of the specimens is calculated using the following formula: ; ; ; Based on calculations, the amount of steel slag-coated asphalt is 3.7% based on the specific surface area of ​​the steel slag and the thickness of the asphalt film, and the composite density of the steel slag-asphalt mixture is 3.06 g / cm³. 3 The density of the prepared steel slag asphalt mixture was determined to be 2.01 g / cm³ by Marshall compaction test. 3 The porosity of the specimen was 34.3%.

[0034] According to the volumetric filling theory, newly added asphalt, 0-5mm old asphalt mixture, copper tailings, and 3-5mm steel slag fill the voids formed by asphalt-coated steel slag with 5-10mm and 10-15mm diameter particles. The remaining void ratio is the design void ratio of the solid waste-based road surface material. The composite compaction density of the coarse aggregate and steel slag is 1.67 g / cm³. 3 Calculate the amounts of steel slag, 0-5mm old asphalt mixture, and copper tailings according to the following formula, with the porosity of the asphalt mixture taken as 4%: ; + + + =100; Based on the gradation requirements of 2.36mm and 0.075mm sieve passing rates, calculate the dosage of 0-5mm old asphalt mixture, copper tailings, and 3-5mm steel slag according to the following formula. ; ; Calculate the specific surface area of ​​old asphalt mixture and copper tailings using the following formula: ; ; ; Asphalt coats the surface of steel slag to form an asphalt film, and some asphalt enters the internal pores of the steel slag. The amount of new asphalt is calculated by combining the amount of asphalt in the old asphalt mixture. ; + + ; Calculations show that the specific surface area of ​​0-5mm old asphalt mixture is 11.7m². 2 / kg. The specific surface area of ​​copper tailings is 20.7m². 2 / kg, the asphalt film thickness of the old asphalt mixture is 6.9um, and the final raw material proportions are shown in Table 7 below: Table 7 Proportion of Each Raw Material

[0035] Solid waste-based pavement surface material was prepared according to the above proportions, and indoor tests were conducted. The results are shown below: Based on the above design results, SBS modified asphalt was used to prepare steel slag asphalt mixture, and its various properties were tested. The results are shown in Table 8 below: Table 8 Mixture Properties

[0036] Prepare solid waste-based pavement surface material according to the above proportions at the mixing plant, transport the solid waste-based pavement surface material to the site for paving, and conduct quality inspection immediately after compaction.

[0037] The test results are shown in Table 9 below: Table 9. Test results of road base materials after construction

[0038] As shown in Table 9, the solid waste-based pavement surface material prepared by the proportion determined by the method of the present invention meets the specification requirements.

[0039] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for confirming the mix proportion of solid waste-based road surface material, characterized in that, Includes the following steps: S1. The surface material of the solid waste base road includes copper tailings, steel slag, old asphalt mixture and new asphalt. Among them, steel slag is divided into fine aggregate steel slag and coarse aggregate steel slag according to particle size. Copper tailings and steel slag of various particle sizes are screened to determine the gradation composition of steel slag and copper tailings of various particle sizes. Extraction tests are conducted on old asphalt mixture to determine its gradation composition and asphalt content. S2. Design the gradation of the surface material for solid waste-based pavement and determine the proportion of steel slag to be added. S3. Take steel slag of each particle size with an average weight of ≥500g as steel slag samples. Calculate the specific surface area of ​​steel slag samples of each particle size based on the thickness of the water film on the surface of the steel slag samples and the volume of adsorbed water. S4. Based on the theory of asphalt film formation, the amount of asphalt coated with steel slag is calculated by combining the specific surface area of ​​steel slag and the thickness of the asphalt film. Marshall specimens are prepared according to the amount of steel slag and asphalt in the coarse aggregate, and the porosity of the specimens is calculated. S5. According to the volume filling theory, some of the newly added asphalt, old asphalt mixture, copper tailings, and fine aggregate steel slag are filled in the voids formed by the newly added asphalt coating the coarse aggregate steel slag. The remaining void ratio is the design void ratio of the solid waste base pavement surface material. Based on the gradation requirements of 2.36mm and 0.075mm sieve passing rates, calculate the amount of old asphalt mixture, copper tailings, and fine aggregate steel slag. S6. Based on the specific surface area of ​​steel slag, the specific surface area of ​​copper tailings, the specific surface area of ​​aggregates in the old asphalt mixture, and the optimal asphalt film thickness, and in conjunction with the asphalt content in the old asphalt mixture, calculate the amount of new asphalt to be added.

2. The method for confirming the mix proportion of solid waste-based road surface material according to claim 1, characterized in that, In step S3, steel slag samples of each particle size are soaked in water for 24 hours, filtered, and poured into iron cups. The bottom of the iron cups is lined with absorbent paper, and the top is separated by filter paper. The cups are then placed in a centrifuge and centrifuged for 2-3 minutes. The mass of the steel slag samples is then measured. After drying, the mass is measured again, and the specific surface area of ​​the steel slag samples of each particle size is calculated using the following formula: ； ； In the formula: —The mass of the steel slag sample after immersion in water and centrifugation to remove pore water, in grams; —The mass of the steel slag sample after immersion in water and centrifugation, in grams; —Volume water absorption rate of steel slag sample, % ρ s —Density of water, g / cm³ 3 ; ρ k —Density of the steel slag sample, g / cm³ 3 ; —The mass of the steel slag sample after the surface water has been absorbed, in grams; SA—Specific surface area of ​​steel slag sample, m² 2 / kg; μ s —Water film thickness, in μm; —The mass of the steel slag sample taken, in grams.

3. The method for confirming the mix proportion of solid waste-based road surface material according to claim 1, characterized in that, The porosity of the specimen is calculated using the following formula: ； ； ； In the formula: —When steel slag is coated with asphalt at the optimal asphalt film thickness, the percentage of asphalt is %. μ—the average thickness of the bitumen film formed by bitumen coating on the surface of steel slag and copper tailings, in μm; ρ a —Density of asphalt, g / cm³ 3 ; SA1—Specific surface area of ​​steel slag with a particle size of 5-10 mm in coarse aggregate steel slag, in m² 2 / kg; —The percentage of steel slag with a particle size of 5-10mm in coarse aggregate steel slag, % SA2—Specific surface area of ​​steel slag with a particle size of 10-15mm in coarse aggregate steel slag, in m² 2 / kg; 2—Volume water absorption rate of steel slag with a particle size of 10-15mm in coarse aggregate steel slag, % ρ2—Density of steel slag with a particle size of 10–15 mm in coarse aggregate steel slag, in g / cm³ 3 ; ρ1—Density of steel slag with a particle size of 5–10 mm in coarse aggregate steel slag, g / cm³ 3 ; 1—Volume water absorption rate of steel slag with a particle size of 5-10 mm in coarse aggregate steel slag, % ρ h —The composite density of coarse aggregate steel slag asphalt mixture, g / cm³ 3 ; VC—Porosity of coarse aggregate steel slag asphalt mixture, % ρ c —Bulk density of coarse aggregate steel slag asphalt mixture, g / cm³ 3 .

4. The method for confirming the mix proportion of solid waste-based road surface material according to claim 1, characterized in that, Calculate the following formulas for the amounts of steel slag, old asphalt mixture, and copper tailings: ； + + + =100； ； + ； In the formula: —The percentage of copper tailings in solid waste-based road surface materials, % ρ w —Density of copper tailings, g / cm³ 3 ; —The proportion of fine aggregate steel slag in solid waste-based pavement surface materials, % ρ g —Density of fine aggregate steel slag, g / cm³ 3 ; —The percentage of used asphalt mixture in solid waste-based pavement surface materials, % ρ j —Density of old asphalt mixture, g / cm³ 3 ; —The percentage of newly added asphalt in solid waste-based pavement surface materials, % —When steel slag is coated with asphalt at the optimal asphalt film thickness, the percentage of asphalt is %. —The proportion of coarse aggregate steel slag in solid waste-based pavement surface materials, % ρ a —Density of freshly added asphalt, g / cm³ 3 ; ρ d —Compacted density of synthetic coarse aggregate steel slag asphalt mixture, g / cm³ 3 ; VC—Porosity of coarse aggregate steel slag asphalt mixture, % VV—Design porosity of solid waste-based road surface material, %, ranging from 3% to 5%; —Copper tailings throughput of 0.075mm; —The aggregate passing rate of the extracted old asphalt mixture is 0.075mm; —Fine aggregate steel slag passing rate of 2.36mm; —The aggregate passing rate of the extracted old asphalt mixture is 2.36mm; —Copper tailings throughput of 2.36mm; —Graining requirement is a passing rate of 0.075mm, taken as 8-12; —Graining requirement is 2.36mm passing rate, take 18~22.

5. The method for confirming the mix proportion of solid waste-based road surface material according to claim 1, characterized in that, Calculate the amount of new asphalt to be added using the following formula; ； + + ； In the formula: —The average thickness of the asphalt film on the aggregate surface in the old asphalt mixture, in μm; —Percentage of asphalt in old asphalt mixture, % —Density of the old asphalt mixture after extraction, in g / cm³ 3 ; SA j —Specific surface area of ​​aggregates in old asphalt mixture, m² 2 / kg; —The percentage of newly added asphalt in solid waste-based pavement surface materials, % —When steel slag is coated with asphalt at the optimal asphalt film thickness, the percentage of asphalt is %. —The proportion of coarse aggregate steel slag in solid waste-based pavement surface materials, % —The percentage of copper tailings in solid waste-based road surface materials, % —The average thickness of the asphalt film formed by the asphalt coating on the surface of steel slag and copper tailings, in μm; ρ a —Density of freshly added asphalt, g / cm³ 3 ; SA w —Specific surface area of ​​copper tailings, m 2 / kg; —The percentage of used asphalt mixture in solid waste-based pavement surface materials, % SA3—Specific surface area of ​​fine aggregate steel slag, m² 2 / kg; —The proportion of fine aggregate steel slag in solid waste-based pavement surface materials, % —Volume water absorption rate of fine aggregate steel slag, % ρ g —Density of fine aggregate steel slag, g / cm³ 3 .

6. The method for confirming the mix proportion of solid waste-based road surface material according to claim 1, characterized in that, The specific surface area of ​​the old asphalt mixture and copper tailings is calculated according to the following formula: ； ； ； In the formula: —Average particle size of copper tailings, mm; —Sieve aperture size, mm; —The size of the sieve aperture of the previous sieve in the i-th sieve, in mm; —Copper tailings in the sieve The sieve residue, % SA w —Specific surface area of ​​copper tailings, m 2 / kg; ρ w —Density of copper tailings, g / cm³ 3 ; SA j —Specific surface area of ​​aggregates in old asphalt mixture, m² 2 / kg; a—Passing rate of aggregates in old asphalt mixture through a 4.75mm sieve; b—Passing rate of aggregates in old asphalt mixture through a 2.36 mm sieve; c—Passing rate of aggregates in old asphalt mixture through a 1.18 mm sieve; d—Passage of aggregates in old asphalt mixture through a 0.6 mm sieve; e—The passing rate of aggregates in old asphalt mixtures through a 0.3mm sieve; f—the passing rate of aggregates in old asphalt mixtures through a 0.15mm sieve; g—The passing rate of aggregates in old asphalt mixtures through a 0.075 mm sieve.

7. The method for confirming the mix proportion of solid waste-based road surface material according to claim 1, characterized in that: The newly added asphalt is SBS modified asphalt; the moisture content of the old asphalt mixture is ≤2.0%, and the old asphalt in the old asphalt mixture is old SBS modified asphalt; the water film thickness is 7-10 μm, and the optimal asphalt film thickness is 8-12 μm.

8. The method for confirming the mix proportion of solid waste-based road surface material according to claim 1, characterized in that: The copper tailings have a particle size ≤ 0.6 mm, and the copper tailings 0.075 mm passing rate ≥ 60%; the fine aggregate steel slag has a particle size of 3-5 mm, the coarse aggregate steel slag has a particle size of 5-10 mm and a particle size of 10-15 mm; the old asphalt mixture has a particle size of 0-5 mm.

9. A solid waste-based pavement surface material prepared by the proportioning confirmation method according to any one of claims 1-8.

10. An application of the solid waste-based pavement surface material as described in claim 9, characterized in that, Includes the following steps: (1) Based on the proportions of each grade of material determined by the mix design, the mixing plant prepares the solid waste base pavement surface material; (2) Transport the solid waste base pavement surface material to the site for paving and compaction; (3) After compaction is completed, a quality inspection shall be carried out in accordance with the relevant specifications.

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