A method for determining the mix proportion of steel slag asphalt mixture

Abstract

This invention belongs to the field of road engineering technology, specifically a method for determining the mix proportion of steel slag asphalt mixtures. The specific steps of this invention are as follows: S1, screening the raw materials steel slag, manufactured sand, and copper tailings to determine their gradation composition; S2, obtaining the specific surface area of ​​steel slag using three-dimensional laser scanning technology; S3, detecting and calculating the amount of asphalt adhering to the surface of the steel slag and entering the pores within the steel slag in the steel slag asphalt mixture; S4, preparing specimens and conducting Marshall tests to determine the steel slag ratio under maximum density conditions; S5, calculating the proportions of sand, copper tailings, and steel slag, as well as the asphalt-aggregate ratio of the mixture using a computer. This invention scientifically and accurately calculates the amount of asphalt in the mix proportion of steel slag asphalt mixtures and controls the change process of the mixture in spatial composition through volume parameters, ensuring that the steel slag asphalt mixture has good compaction, achieving controllable material properties and volume parameters, and ensuring that the steel slag asphalt mixture has good road performance.

Description

Technical Field

[0001] This invention belongs to the field of road engineering technology, and in particular relates to a method for determining the mix proportion of steel slag asphalt mixture. Background Technology

[0002] Steel slag is a waste product from the steel production process and belongs to general solid waste. The geometry and mechanical properties of steel slag are basically the same as those of rolled crushed stone. After certain processing, steel slag can be processed into aggregates of different particle sizes, which can replace natural stone. Moreover, steel slag has many pores on its surface, strong adsorption capacity, large internal friction angle, and stronger interlocking effect, making it an excellent raw material for asphalt mixtures.

[0003] Existing methods for determining asphalt mixture proportions first determine the aggregate blending ratio. Asphalt is then coated onto the aggregate surface with a uniform film thickness, and strict requirements are placed on the aggregate's water absorption rate to prevent asphalt from penetrating the aggregate interior. This leads to a discrepancy between the amount of asphalt coated on the aggregate surface and the actual amount used. Steel slag, being a porous material, has more surface openings and stronger adsorption capacity compared to aggregates, allowing more asphalt to penetrate its interior. If the existing proportioning method is strictly followed, the asphalt content will be too low, making it impossible to accurately predict the asphalt content. This severely impacts the performance of steel slag asphalt mixtures, and the performance and volumetric properties of these mixtures cannot be effectively controlled, resulting in significant variability in design results. Furthermore, there is no accurate method for calculating the specific surface area of ​​steel slag, leading to inaccurate asphalt coating on its surface. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, this invention provides a method for determining the mix proportion of steel slag asphalt mixtures. This invention combines the porous characteristics of steel slag, determines its specific surface area, and considers the asphalt coating and film formation state, the amount of asphalt entering the voids, and the mixture volume filling process to design the mix proportion, thereby creating a high-performance and controllable steel slag asphalt mixture.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for determining the mix proportion of steel slag asphalt mixture includes the following steps:

[0007] S1. Steel slag asphalt mixture includes steel slag, manufactured sand, copper tailings and asphalt. The steel slag, manufactured sand and copper tailings are screened to determine their gradation composition and the water absorption rate of steel slag is measured.

[0008] S2. Select 20-40 steel slag samples, weigh the mass of each steel slag sample, place each steel slag sample on the worktable, use the three-dimensional laser scanning method to obtain the point cloud data of each steel slag sample, align and merge the point clouds from different perspectives, and then convert the point cloud data into a three-dimensional network model to calculate the specific surface area of ​​the steel slag.

[0009] S3. Immerse the above steel slag sample in hot asphalt for 5-10 minutes. Take out the steel slag coated with asphalt and immerse it in water. Measure the volume of the steel slag after immersion in asphalt. Steel slag has many pores. Some asphalt coats the surface of the steel slag to form an asphalt film, and some asphalt enters the pores. Calculate the amount of asphalt entering the pores of the steel slag based on the volume of asphalt adsorbed after immersion in asphalt and the thickness of the asphalt film coating the surface of the steel slag.

[0010] S4. Steel slag is constructed according to its maximum density state. Based on the skeleton structure theory and the film-forming characteristics of asphalt, asphalt coats the steel slag to form the basic skeleton of the asphalt mixture, with some asphalt entering the voids in the steel slag. Asphalt uniformly coats the manufactured sand and copper tailings with a certain asphalt film thickness, filling the voids formed under the compacted state of the steel slag coated with asphalt. The amount of manufactured sand and copper tailings coated by asphalt is calculated based on the specific surface area of ​​the manufactured sand and copper tailings and the asphalt film-forming state. The remaining voids are the porosity of the steel slag asphalt mixture. Then, combined with the changes in volume parameters of the raw materials during the volume filling process, the composition ratio of steel slag, manufactured sand, and copper tailings, as well as the asphalt-aggregate ratio of the mixture, are determined.

[0011] Preferably, the steel slag includes steel slag with a particle size of 10mm ≤ < 15mm and steel slag with a particle size of 5mm ≤ < 10mm; in step S2, 10 to 20 steel slag samples with a particle size of 10mm ≤ < 15mm and 10 to 20 steel slag samples with a particle size of 5mm ≤ < 10mm are selected, the mass of each steel slag sample is weighed, and the specific surface area of ​​the steel slag is calculated according to the following formula:

[0012] ;

[0013] Where: SA - specific surface area of ​​the steel slag sample, m 2 / kg;

[0014] k—Number of steel slag samples;

[0015] S i G —The surface area (cm²) of the i-th steel slag sample extracted from the three-dimensional network model. 2 ;

[0016] ρ i G —Dry density of the i-th steel slag sample, g / cm³ 3 ;

[0017] V i G —Volume of the i-th steel slag sample, in cm³ 3 .

[0018] Preferably, the amount of asphalt entering the pores of the steel slag is calculated according to the following formula:

[0019] ;

[0020] In the formula: α G —The amount of asphalt entering the pores of steel slag under unit water absorption rate, %

[0021] k—Number of steel slag samples;

[0022] ρ i G —Dry density of the i-th steel slag sample, g / cm³ 3 ;

[0023] V i jG —Volume of the i-th steel slag sample after immersion in hot asphalt, in cm³ 3 ;

[0024] V i G —Volume of the i-th steel slag sample, in cm³ 3 ;

[0025] μ—Asphalt film thickness, in μm;

[0026] ρ a —Density of asphalt, g / cm³ 3 ;

[0027] S i G —The surface area (cm²) of the i-th steel slag sample extracted from the three-dimensional network model. 2 ;

[0028] ω i G —Water absorption rate of the i-th steel slag sample, %

[0029] m i G —Mass of the i-th steel slag sample, g.

[0030] Preferably, the maximum density state of steel slag refers to mixing steel slag with a particle size of 10mm ≤ < 15mm and steel slag with a particle size of 5mm ≤ < 10mm in a ratio of (0+A):(100-A), calculating the amount of asphalt adsorbed and absorbed into the voids by the steel slag, conducting tests according to the Marshall compaction method, measuring its porosity, and drawing a graph showing the relationship between porosity and the ratio of steel slag with a particle size of 10mm ≤ < 15mm and steel slag with a particle size of 5mm ≤ < 10mm. The ratio of steel slag with a particle size of 10mm ≤ < 15mm and steel slag with a particle size of 5mm ≤ < 10mm when the porosity VC is the minimum is the maximum density state of the steel slag mixture.

[0031] Preferably, the amount of asphalt used to coat and adsorb steel slag into its pores is calculated according to the following formula:

[0032] ;

[0033] ;

[0034] %

[0035] Where: P1—Marshall test asphalt-aggregate ratio for maximum compaction of steel slag and asphalt mixture, %;

[0036] ρ a —Density of asphalt, g / cm³ 3 ;

[0037] μ—Asphalt film thickness, in μm;

[0038] A — Take one of the values ​​0, 20, 40, 60, 80, and 100;

[0039] Specific surface area of ​​SA1-10mm≤particle size<15mm steel slag, m² 2 / kg;

[0040] Specific surface area of ​​SA2-5mm ≤ particle size < 10mm steel slag, m² 2 / kg;

[0041] α G1 The amount of asphalt entering the voids under unit water absorption rate of steel slag with a particle size of 10mm ≤ particle size < 15mm, %

[0042] α G2 The amount of asphalt entering the voids under unit water absorption rate of steel slag with a particle size of 5mm ≤ Particle size < 10mm, %

[0043] Water absorption rate of steel slag with particle size ≤ 10mm and < 15mm, %

[0044] Water absorption rate of steel slag with a particle size of ω2—5mm≤particle size<10mm, %

[0045] ρ s0 —The combined density of steel slag and asphalt, g / cm³ 3 ;

[0046] ρ s1 Density of steel slag with a particle size of 10mm ≤ particle size < 15mm, g / cm³ 3 ;

[0047] ρ s2 Density of steel slag with a particle size of 5mm ≤ particle size < 10mm, g / cm³ 3 ;

[0048] YOU —The porosity of a mixture of steel slag and asphalt was determined by Marshall test, %;

[0049] ρ sc —The bulk density of a mixture of steel slag and asphalt was determined by a Marshall test, in g / cm³. 3 .

[0050] Preferably, the changes in volumetric parameters of raw materials during the volume filling process are used to determine the composition ratio of steel slag, manufactured sand, and tailings, as well as the asphalt-aggregate ratio in the steel slag asphalt mixture, according to the following formula:

[0051] ;

[0052] ;

[0053] ;

[0054] = ;

[0055] Where: G—the proportion of steel slag, %

[0056] g—the proportion of manufactured sand, %

[0057] f—the proportion of tailings, %

[0058] ρ g —Density of manufactured sand, g / cm³ 3 ;

[0059] ρ f —Density of copper tailings, g / cm³ 3 ;

[0060] YOU —The porosity of a mixture of steel slag and asphalt was determined by Marshall test, %;

[0061] ρ sc —The bulk density of a mixture of steel slag and asphalt was determined by a Marshall test, in g / cm³. 3 ;

[0062] VMA—Void ratio of aggregate in steel slag asphalt mixture, %

[0063] VV—Porosity of steel slag asphalt mixture, %

[0064] SA g —Specific surface area of ​​manufactured sand, m² 2 / kg;

[0065] SA f —Specific surface area of ​​manufactured sand, m² 2 / kg;

[0066] ρ a —Density of asphalt, g / cm³ 3;

[0067] μ—Asphalt film thickness, in μm;

[0068] P a —Oil-to-stone ratio, %

[0069] P1—Marshall test asphalt-aggregate ratio, representing the maximum density of the steel slag and asphalt mixture.

[0070] Preferably, the specific surface area of ​​manufactured sand and copper tailings is calculated according to the following formula:

[0071] ;

[0072] Where: SA - specific surface area of ​​the material, m 2 / kg;

[0073] a—The material's throughput through a 4.75mm sieve;

[0074] b—the material's throughput through a 2.36 mm sieve;

[0075] c—the material's throughput through a 1.18 mm sieve.

[0076] d—the material's throughput through a 0.6 mm sieve.

[0077] e—the material's throughput through a 0.3 mm sieve;

[0078] x—the material's throughput through a 0.15mm sieve;

[0079] y—the material's throughput through a 0.075mm sieve.

[0080] In this formula, the coefficient preceding the pass rate all include units, m. 2 / kg.

[0081] Preferably, the asphalt is SBS modified asphalt, and the asphalt used in the hot asphalt impregnation of steel slag and the steel slag asphalt mixture is the same asphalt, and the thickness of the asphalt film is 9~13um.

[0082] Preferably, the design void ratio of steel slag asphalt mixture is 3% to 6%, and the design aggregate void ratio of steel slag asphalt mixture is 13% to 15%.

[0083] Preferably, the particle size of the manufactured sand is <4.75mm; the particle size of the copper tailings is ≤2.36mm, and the proportion of copper tailings with a particle size less than 0.75mm is 40%~50%.

[0084] The advantages of this invention are:

[0085] (1) This invention scientifically and accurately calculates the amount of asphalt in the mix proportion of steel slag asphalt mixture, and controls the change process of the mixture in space by controlling the volume parameters, so as to ensure that the steel slag asphalt mixture has good compactness, realizes the controllability of material properties and volume parameters, and ensures that the steel slag asphalt mixture has good road performance.

[0086] (2) In view of the defects in the process of determining the proportion of steel slag asphalt mixture, such as not considering the entry of asphalt into the pores of steel slag, inaccurate specific surface area of ​​steel slag, and inability to accurately predict the amount of asphalt used, this invention provides a method based on the porous characteristics of steel slag, considering the amount of asphalt entering the pores of steel slag, simulating the three-dimensional geometric state of steel slag to determine its specific surface area, and accurately predicting the amount of asphalt used in the mixture based on the film formation state of asphalt on the surface of steel slag and the amount of asphalt entering the pores of steel slag, thereby improving the performance of steel slag asphalt mixture.

[0087] (3) The method for determining the mix proportion of steel slag asphalt mixture provided by the present invention combines the characteristics of steel slag being porous and having strong adsorption. By measuring the amount of asphalt entering the pores of steel slag with different water absorption rates, a model is established to show the relationship between the water absorption rate of steel slag and the amount of asphalt entering the pores of steel slag. In the method for determining the mix proportion, a portion of the asphalt enters the pores of steel slag, and a portion of the asphalt is coated on the surface of steel slag, manufactured sand, and copper tailings with a uniform asphalt film thickness. Thus, a scientific and accurate method for calculating the amount of asphalt in the mix proportion of steel slag asphalt mixture is proposed, ensuring that the designed steel slag asphalt mixture has good performance in terms of high temperature, low temperature, and water stability.

[0088] (4) The method for determining the proportion of steel slag asphalt mixture provided by the present invention establishes a three-dimensional solid model of steel slag, accurately calculates the specific surface area of ​​steel slag, and calculates the amount of asphalt used to coat steel slag by using the specific surface area of ​​steel slag and the thickness of asphalt film, thereby ensuring the accuracy of the calculation of asphalt amount in the process of determining the proportion of steel slag asphalt mixture, and thus effectively predicting the asphalt-aggregate ratio of steel slag asphalt mixture.

[0089] (5) The method for determining the proportion of steel slag asphalt mixture provided by the present invention is designed according to the principle of volume filling. The change process of the mixture in the space is controlled by the volume parameters. The raw materials are filled densely and have a good interlocking effect, thereby ensuring that the steel slag asphalt mixture has good compactness and realizing the controllability of the mixture performance and volume parameters.

[0090] (6) The method for determining the proportion of steel slag asphalt mixture provided by the present invention uses steel slag as raw material, controls the proportion of steel slag by volume parameters, improves the utilization rate of steel slag, provides an effective solution for solid waste accumulation and road construction material shortage, and realizes the recycling of solid waste. Detailed Implementation

[0091] 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.

[0092] A method for determining the mix proportion of steel slag asphalt mixture includes five components: steel slag with a particle size of 10-15 mm, steel slag with a particle size of 5-10 mm, manufactured sand with a particle size of <4.75 mm, copper tailings with a particle size of ≤2.36 mm, and asphalt. The steel slag, manufactured sand, and copper tailings are screened to determine their gradation composition, and the water absorption rate of the steel slag is tested. The results are shown in Tables 1-2 below.

[0093] Table 1 Raw material screening results

[0094]

[0095] Table 2 Raw material screening results

[0096]

[0097] Thirteen steel slag samples each with a particle size of 10mm ≤ < 15mm and 5mm ≤ < 10mm were selected. The mass of each steel slag sample was weighed, and each sample was placed on a worktable. Point cloud data for each steel slag was acquired using a three-dimensional laser scanning method. The point clouds from different perspectives were aligned and merged, and the point cloud data was converted into a three-dimensional network model. The specific surface area of ​​the steel slag with a particle size of 10mm ≤ < 15mm and 5mm ≤ < 10mm was calculated according to the following formula. The results are shown in Table 3.

[0098] ;

[0099] ;

[0100] ;

[0101] Table 3 Specific Surface Area of ​​Steel Slag

[0102]

[0103] The steel slag samples were immersed in hot SBS modified asphalt for 5-10 minutes. The asphalt-coated steel slag was then removed and immersed in water, and the volume of the steel slag after immersion in asphalt was measured. Based on the volume of asphalt adsorbed by the steel slag after immersion and the thickness of the asphalt film coating the surface of the steel slag, the amount of asphalt entering the pores of the steel slag was calculated using the following method. The results are shown in Table 4 below.

[0104] ;

[0105] Table 4. Amount of asphalt entering the voids under unit open void conditions with steel slag

[0106]

[0107] The proportions of 10-15mm steel slag in the total steel slag were taken as 100%, 80%, 60%, 40%, 20%, and 0%, respectively, and the density of asphalt was taken as 1.03 g / cm³. 3 The asphalt film thickness is taken as 12µm. The amount of asphalt used to coat and adsorb steel slag into its pores is calculated according to the following formula:

[0108] ;

[0109] The Marshall compaction method was used to test and determine its porosity. The proportion of steel slag with a particle size of 10 mm ≤ particle size < 15 mm was determined to be 40% at the minimum porosity.

[0110] Table 5. Asphalt-aggregate ratio and porosity of steel slag and asphalt mixture

[0111]

[0112] The specific surface area of ​​manufactured sand is 7.7 m². 2 / kg, the specific surface area of ​​copper tailings is 28.24m². 2 / kg, with a void ratio (VAM) of 13.5% and a porosity of 4.0%, the changes in volumetric parameters of the raw materials during the volume filling process are determined according to the following formulas to determine the composition ratio of steel slag, manufactured sand, and copper tailings in the steel slag asphalt mixture and the asphalt-aggregate ratio of the mixture:

[0113] ;

[0114] ;

[0115] ;

[0116] = ;

[0117] Calculations show that the steel slag asphalt mixture contains 33.2% steel slag (10~15mm), 49.9% steel slag (10~15mm), 12.1% manufactured sand, 4.8% copper tailings, and an asphalt-aggregate ratio of 5.57%.

[0118] Based on the above design results, SBS modified asphalt was used to prepare steel slag asphalt mixture, and its various performance results are shown in Table 6:

[0119] Table 6 Mixture Properties

[0120]

[0121] As can be seen from Table 6, the method for determining the proportion of steel slag asphalt mixture in this invention meets the requirements.

[0122] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of the 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 determining the mix proportion of steel slag asphalt mixture, characterized in that, Includes the following steps: S1. Steel slag asphalt mixture includes steel slag, manufactured sand, copper tailings and asphalt. The steel slag, manufactured sand and copper tailings are screened to determine their gradation composition and the water absorption rate of steel slag is measured. S2. Select 20-40 steel slag samples, weigh the mass of each steel slag sample, use the three-dimensional laser scanning method to obtain the point cloud data of each steel slag sample, and then convert the point cloud data into a three-dimensional network model to calculate the specific surface area of ​​the steel slag. S3. Immerse the above steel slag sample in hot asphalt for 5-10 minutes, take out the steel slag coated with asphalt and immerse it in water, and measure the volume of the steel slag after immersion in asphalt; calculate the amount of asphalt entering the pores of the steel slag based on the volume of asphalt adsorbed by the steel slag after immersion in asphalt and the thickness of the asphalt film coated with asphalt on the surface of the steel slag. S4. Steel slag is constructed according to its maximum density state. Based on the skeleton structure theory and the film-forming characteristics of asphalt, asphalt coats the steel slag to form the basic skeleton of the asphalt mixture, with some asphalt entering the pores of the steel slag. Asphalt uniformly coats the manufactured sand and copper tailings, filling the voids formed under the compacted state of the steel slag coated with asphalt. The amount of manufactured sand and copper tailings coated by asphalt is calculated based on the specific surface area of ​​the manufactured sand and copper tailings and the film-forming state of the asphalt. The remaining voids are the porosity of the steel slag asphalt mixture. Then, combined with the changes in volume parameters of the raw materials during the volume filling process, the proportions of steel slag, manufactured sand, and copper tailings, as well as the asphalt-aggregate ratio of the mixture, are determined.

2. The method for determining the mix proportion of steel slag asphalt mixture according to claim 1, characterized in that, Steel slag includes steel slag with a particle size of 10mm ≤ < 15mm and steel slag with a particle size of 5mm ≤ < 10mm; in step S2, 10 to 20 steel slag samples with a particle size of 10mm ≤ < 15mm and 10 to 20 steel slag samples with a particle size of 5mm ≤ < 10mm are selected, and the mass of each steel slag sample is weighed. The specific surface area of ​​the steel slag is calculated according to the following formula: ； Where: SA - specific surface area of ​​the steel slag sample, m 2 / kg; k—Number of steel slag samples; S i G —The surface area (cm²) of the i-th steel slag sample extracted from the three-dimensional network model. 2 ; ρ i G —Dry density of the i-th steel slag sample, g / cm³ 3 ; V i G —Volume of the i-th steel slag sample, in cm³ 3 .

3. The method for determining the mix proportion of steel slag asphalt mixture according to claim 1, characterized in that the asphalt... The amount entering the pores of steel slag is calculated using the following formula: ； In the formula: α G —The amount of asphalt entering the pores of steel slag under unit water absorption rate, % k—Number of steel slag samples; ρ i G —Dry density of the i-th steel slag sample, g / cm³ 3 ; V i jG —Volume of the i-th steel slag sample after immersion in hot asphalt, in cm³ 3 ; V i G —Volume of the i-th steel slag sample, in cm³ 3 ; μ—Asphalt film thickness, in μm; ρ a —Density of asphalt, g / cm³ 3 ; S i G —The surface area (cm²) of the i-th steel slag sample extracted from the three-dimensional network model. 2 ; ω i G —Water absorption rate of the i-th steel slag sample, % m i G —Mass of the i-th steel slag sample, g.

4. The method for determining the mix proportion of steel slag asphalt mixture according to claim 1, characterized in that: The maximum density composition of steel slag refers to the mixing of steel slag with particle size of 10mm ≤ < 15mm and steel slag with particle size of 5mm ≤ < 10mm in a ratio of (0+A):(100-A), calculating the amount of asphalt adsorbed and absorbed into the voids by the steel slag, conducting tests according to the Marshall compaction method, measuring its porosity, and drawing a graph showing the relationship between porosity and the ratio of steel slag with particle size of 10mm ≤ < 15mm and steel slag with particle size of 5mm ≤ < 10mm. The ratio of steel slag with particle size of 10mm ≤ < 15mm and steel slag with particle size of 5mm ≤ < 10mm when the porosity VC is the minimum is the maximum density composition of the steel slag mixture.

5. The method for determining the mix proportion of steel slag asphalt mixture according to claim 4, characterized in that, The amount of asphalt used to coat and adsorb into the pores of steel slag is calculated using the following formula: ； ； %； Where: P1 - Marshall test asphalt-aggregate ratio for maximum compaction of steel slag and asphalt mixture, %; ρ a —Density of asphalt, g / cm³ 3 ; μ—Asphalt film thickness, in μm; A — Take one of the values ​​0, 20, 40, 60, 80, and 100; Specific surface area of ​​SA1-10mm≤particle size<15mm steel slag, m² 2 / kg; Specific surface area of ​​SA2-5mm ≤ particle size < 10mm steel slag, m² 2 / kg; α G1 The amount of asphalt entering the voids under unit water absorption rate of steel slag with a particle size of 10mm ≤ particle size < 15mm, % α G2 The amount of asphalt entering the voids under unit water absorption rate of steel slag with a particle size of 5mm ≤ Particle size < 10mm, % Water absorption rate of steel slag with particle size ≤ 10mm and < 15mm, % Water absorption rate of steel slag with a particle size of ω2—5mm≤particle size<10mm, % ρ s0 —The combined density of steel slag and asphalt, g / cm³ 3 ; ρ s1 Density of steel slag with a particle size of 10mm ≤ particle size < 15mm, g / cm³ 3 ; ρ s2 Density of steel slag with a particle size of 5mm ≤ particle size < 10mm, g / cm³ 3 ; VC —The porosity of a mixture of steel slag and asphalt was determined by Marshall test, %; ρ sc —The bulk density of a mixture of steel slag and asphalt was determined by a Marshall test, in g / cm³. 3 .

6. The method for determining the mix proportion of steel slag asphalt mixture according to claim 1, characterized in that, The composition ratio of steel slag, manufactured sand, and tailings, as well as the asphalt-aggregate ratio in the steel slag asphalt mixture, should be determined according to the following formula: ； ； ； = ； Where: G—the proportion of steel slag, % g—the proportion of manufactured sand, % f—the proportion of tailings, % ρ g —Density of manufactured sand, g / cm³ 3 ; ρ f —Density of copper tailings, g / cm³ 3 ; VC —The porosity of a mixture of steel slag and asphalt was determined by Marshall test, %; ρ sc —The bulk density of a mixture of steel slag and asphalt was determined by a Marshall test, in g / cm³. 3 ; VMA—Void ratio of aggregate in steel slag asphalt mixture, % VV—Porosity of steel slag asphalt mixture, % SA g —Specific surface area of ​​manufactured sand, m² 2 / kg; SA f —Specific surface area of ​​manufactured sand, m² 2 / kg; ρ a —Density of asphalt, g / cm³ 3 ; μ—Asphalt film thickness, in μm; P a —Oil-to-stone ratio, % P1—Marshall test asphalt-aggregate ratio, representing the maximum density of the steel slag and asphalt mixture.

7. The method for determining the mix proportion of steel slag asphalt mixture according to claim 1, characterized in that, The specific surface area of ​​manufactured sand and copper tailings is calculated using the following formula: ； Where: SA—specific surface area of ​​the material, m 2 / kg; a—The material's throughput through a 4.75mm sieve. b—the material's throughput through a 2.36 mm sieve; c—the material's throughput through a 1.18 mm sieve. d—the material's throughput through a 0.6 mm sieve. e—the material's throughput through a 0.3 mm sieve; x—the material's throughput through a 0.15mm sieve; y—the material's throughput through a 0.075mm sieve.

8. The method for determining the mix proportion of steel slag asphalt mixture according to claim 1, characterized in that: The asphalt is SBS modified asphalt, and the asphalt used in the hot asphalt impregnation of steel slag and the steel slag asphalt mixture is the same asphalt. The thickness of the asphalt film is 9~13um.

9. The method for determining the mix proportion of steel slag asphalt mixture according to claim 1, characterized in that: The designed void ratio of the steel slag asphalt mixture is 3% to 6%, and the designed aggregate void ratio of the steel slag asphalt mixture is 13% to 15%.

10. The method for determining the mix proportion of steel slag asphalt mixture according to claim 1, characterized in that: The particle size of the manufactured sand is <4.75mm; the particle size of the copper tailings is ≤2.36mm, and the proportion of copper tailings with a particle size less than 0.75mm is 40%~50%.

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