Mixing Method and Uniformity Evaluation Method of Asphalt Mixture Containing Steelmaking Slag

Abstract

The present invention discloses a mixing method and a uniformity evaluation method for asphalt mixture containing steel-making slag, belonging to the technical field of road engineering. The mixing method for asphalt mixture containing steel-making slag comprises the following steps: placing steel-making slag and coarse aggregate with the same volume into a magnetic stirring device, adjusting the magnetic field intensity of an electromagnet to make the gravity received by the steel-making slag and the coarse aggregate the same, so as to obtain a balanced current; adding raw materials including the steel-making slag, the coarse aggregate, fine aggregate, mineral powder and asphalt into the magnetic stirring device, energizing the electromagnet and maintaining the balanced current, and mixing to obtain the asphalt mixture containing steel-making slag. The mixing method of the present invention, through the electromagnet in the magnetic stirring device, makes the gravity received by the steel-making slag and the coarse aggregate with the same volume the same, eliminating or significantly reducing the influence of the large density of the steel-making slag on the uneven mixing of the mixture.

Description

Technical Field

[0001] The present invention relates to the technical field of road engineering, and particularly relates to a mixing method and a uniformity evaluation method for a steel-smelting waste residue asphalt mixture. Background Art

[0002] In recent years, China's steel industry has developed rapidly. While the scale of steel production has been continuously expanding, tens of millions of tons of industrial by-products - steel-smelting waste residues have been generated. The continuous increase in the quantity of steel-smelting waste residues as industrial by-products not only occupies a large amount of land but also causes serious environmental pollution, and is also a waste of resources for the steel-smelting waste residues themselves. Recycling and reusing steel-smelting waste residues as solid waste resources, such as using steel-smelting waste residues as aggregates for asphalt pavements, has been proven to be feasible. Using steel-smelting waste residues as road engineering aggregates not only saves resources and reduces the highway project cost but also has positive significance in terms of environmental protection.

[0003] However, the density of steel-smelting waste residues is significantly higher than that of conventional aggregates, which leads to segregation during the mixing process of the steel-smelting waste residue asphalt mixture, resulting in the problem of uneven mixing of the mixture, affecting the overall performance such as the compaction degree and strength of the steel-smelting waste residue asphalt mixture, and reducing the service life of the asphalt pavement. To ensure the performance of the steel-smelting waste residue asphalt mixture, it is necessary to develop a mixing method and a uniformity evaluation method for the steel-smelting waste residue asphalt mixture. Summary of the Invention

[0004] Aiming at the problems existing in the above prior art, the present invention provides a mixing method and a uniformity evaluation method for a steel-smelting waste residue asphalt mixture. The mixing method of the steel-smelting waste residue asphalt mixture of the present invention generates an upward magnetic force on the steel-smelting waste residue through an electromagnet arranged in the upper-middle part of the magnetic stirring device, so that the same volume of steel-smelting waste residue and coarse aggregate are subjected to the same gravity, which can eliminate or significantly reduce the influence of the large density of the steel-smelting waste residue on the uneven mixing of the mixture. Specifically, it is realized through the following technology.

[0005] A mixing method for a steel-smelting waste residue asphalt mixture includes the following steps:

[0006] Place the same volume of steel-smelting waste residue and coarse aggregate in a magnetic stirring device, adjust the magnetic field strength of the electromagnet so that the steel-smelting waste residue and the coarse aggregate are subjected to the same gravity, and obtain a balanced current;

[0007] Add raw materials including the steel-smelting waste residue, the coarse aggregate, fine aggregate, mineral powder, and asphalt into the magnetic stirring device, energize the electromagnet and maintain the balanced current, and mix to obtain a steel-smelting waste residue asphalt mixture.

[0008] The mixing of asphalt mixture containing steelmaking slag is uneven mainly because there are significant differences in the densities of steelmaking slag and conventional coarse aggregates. As a result, the gravitational forces on the same volume of steelmaking slag and conventional coarse aggregates are significantly different, and the steelmaking slag is prone to sink during the mixing process, leading to uneven mixing of the asphalt mixture. In the present invention, an electromagnetic field is added to the magnetic stirring device to generate an upward magnetic force on the steelmaking slag, offsetting a part of the gravitational force. By adjusting the current in the electromagnet, the magnetic field strength generated by the electromagnet can be adjusted, thereby adjusting the magnetic force received by the steelmaking slag. When the current in the electromagnet reaches a certain value such that the gravitational forces on the same volume of steelmaking slag and conventional coarse aggregates are the same, it is the balance current. Mixing the asphalt mixture containing steelmaking slag in this state can eliminate or significantly reduce the influence of the large density of steelmaking slag on the uneven mixing of the mixture.

[0009] Further, by weight percentage, the asphalt mixture containing steelmaking slag includes 20 - 60% of the mixture of steelmaking slag and coarse aggregates, 25 - 65% of fine aggregates, 0 - 10% of mineral powder, and 2 - 6% of asphalt.

[0010] Further, the particle sizes of both the steelmaking slag and the coarse aggregates are 4.75 - 19 mm.

[0011] Further, the particle size of the fine aggregates is less than 4.75 mm.

[0012] Further, the mixing time is not less than 55 s.

[0013] Further, the steelmaking slag includes at least one of blast furnace ironmaking slag, converter steel slag, open - hearth steel slag, and electric - furnace steel slag generated during the steel - making process. Converter steel slag, open - hearth steel slag, and electric - furnace steel slag can all be called steel slag particles.

[0014] Further, the coarse aggregates include at least one of limestone aggregates, basalt aggregates, and diabase aggregates.

[0015] Further, the method for obtaining the balance current includes the following steps:

[0016] Put the steelmaking slag and the coarse aggregates into containers with the same weight respectively, then hang the containers under the dynamometers respectively, and place the smelting slag and the coarse aggregates at the same height inside the magnetic stirring device;

[0017] Connect the power supply of the electromagnet, adjust the current intensity in the electromagnet. When it is observed that the readings of the two dynamometers hanging the steelmaking slag and the coarse aggregates are the same, record the current of the electromagnet, which is the balance current.

[0018] A magnetic stirring device for asphalt mixture containing steel-making slag, with a feed inlet and an electromagnet provided at its upper part, and stirring devices are provided on both inner walls. The stirring device includes a stirring shaft, a fixed tooth shaft and stirring teeth. The fixed tooth shaft is fixedly connected to the stirring shaft, and several stirring teeth are fixedly connected to the fixed tooth shaft. The fixed tooth shaft of one side of the stirring device is longer than the fixed tooth shaft of the other side of the stirring device; a discharge baffle and a discharge outlet are provided at the lower part of the magnetic stirring device.

[0019] Further, electromagnets are symmetrically arranged at the upper part of the inner wall of the magnetic stirring device.

[0020] A method for evaluating the uniformity of asphalt mixture containing steel-making slag includes the following steps:

[0021] For the well-mixed asphalt mixture containing steel-making slag, samples are taken, weighed respectively at the upper, middle and lower positions, and the masses are recorded as M 0上 、M 0中 、M 0下 ;

[0022] The samples at the upper, middle and lower positions are respectively burned, and the aggregate mixture without asphalt is obtained after burning, and its mass is weighed and recorded as M 1上 、M 1中 、M 1下 ;

[0023] Measure the volumes of the samples at the upper, middle and lower positions after burning, and record them as V 上 、V 中 、V 下 ;

[0024] Calculate the deviation Δρ of the average density of the samples at the upper, middle and lower positions according to formula I; calculate the deviation ΔR of the average volume dosage of asphalt according to formula II; where,

[0025] (Formula I);

[0026] (Formula II);

[0027] According to the results of the deviation Δρ of the average density of the samples at the upper, middle and lower positions and the deviation ΔR of the average volume dosage of asphalt, judge the mixing uniformity of the asphalt mixture containing steel-making slag according to the following method:

[0028] When Δρ ≤ 0.2 g / cm 3 and ΔR ≤ 0.01 g / cm 3 , the mixture is evenly mixed;

[0029] When Δρ > 0.2 g / cm 3 or ΔR > 0.01 g / cm 3When the mixing is uneven for the mixture.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] 1. For the mixing method of the steel-smelting waste residue asphalt mixture of the present invention, by means of the electromagnet provided in the upper-middle part of the magnetic stirring device, the gravity received by the steel-smelting waste residue and the coarse aggregate with the same volume is the same, which can eliminate or significantly reduce the influence of the large density of the steel-smelting waste residue on the uneven mixing of the mixture;

[0032] 2. The operation of the magnetic stirring device of the present invention is simple. Sampling ports are arranged at the upper, middle and lower positions on the side wall, which is convenient for sampling and detecting the uniformity of the steel-smelting waste residue asphalt mixture; the stirring device is arranged on the side wall of the magnetic stirring device, and strip-shaped stirring teeth are used for stirring, which is more conducive to the uniform mixing of the steel-smelting waste residue, coarse aggregate, fine aggregate, mineral powder and asphalt;

[0033] 3. The method for evaluating the uniformity of the steel-smelting waste residue asphalt mixture of the present invention is simple to operate and the results are reliable. Description of the Drawings

[0034] Figure 1 is the magnetic stirring device of the present invention;

[0035] In the figure: 1, feed inlet; 2, inner top wall; 3, electromagnet; 4, stirring teeth; 5, stirring shaft; 6, sampling port; 7, fixed tooth shaft; 8, sampling baffle; 9, discharge port; 10, discharge baffle. Detailed Embodiments

[0036] In order to further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below in conjunction with embodiments, but they cannot be understood as limiting the protection scope of the present invention.

[0037] The present invention provides an exemplary mixing method for a steel-smelting waste residue asphalt mixture, including the following steps:

[0038] In the magnetic stirring device, add the steel-smelting waste residue and the coarse aggregate with the same volume, adjust the magnetic field strength of the electromagnet to make the gravity received by the steel-smelting waste residue and the coarse aggregate the same, and obtain the balanced current;

[0039] Add raw materials including the steel-smelting waste residue and the coarse aggregate into the magnetic stirring device, energize the electromagnet and maintain the balanced current, and mix to obtain the steel-smelting waste residue asphalt mixture;

[0040] The raw materials also include other fine aggregates, mineral powder, asphalt, etc.

[0041] In some examples of the present invention, by weight percentage, the steel-smelting waste slag asphalt mixture may include 20-60% of the mixture of steel-smelting waste slag and coarse aggregate, 25-65% of fine aggregate, 0-10% of mineral powder, and 2-6% of asphalt.

[0042] In some examples of the present invention, the particle sizes of both the steel-smelting waste slag and the coarse aggregate may be 4.75-19 mm.

[0043] In some examples of the present invention, the particle size of the fine aggregate may be less than 4.75 mm.

[0044] In some examples of the present invention, the mixing time may be not less than 55 s.

[0045] In some examples of the present invention, the coarse aggregate may include at least one of limestone aggregate, basalt aggregate, and diabase aggregate.

[0046] In the present invention, the steel-smelting waste slag may include all solid particles having a magnetic effect. In some examples of the present invention, the steel-smelting waste slag may include at least one of blast furnace slag, converter slag, open hearth furnace slag, and electric furnace slag generated during the steel-smelting process.

[0047] The present invention also exemplarily provides a method for evaluating the uniformity of a steel-smelting waste slag asphalt mixture, including the following steps:

[0048] For the well-mixed steel-smelting waste slag asphalt mixture, samples are taken, weighed, and the masses are respectively denoted as M 0上 、M 0中 、M 0下 ;

[0049] The samples at the upper, middle, and lower positions are respectively burned, and the aggregate mixture without asphalt is obtained after burning, and its mass is weighed and denoted as M 1上 、M 1中 、M 1下 ;

[0050] The volumes of the samples at the upper, middle, and lower positions after burning are measured and respectively denoted as V 上 、V 中 、V 下 ;

[0051] Calculate the deviation Δρ of the average density of the samples at the upper, middle, and lower positions according to Formula I; calculate the deviation ΔR of the average volume dosage of asphalt according to Formula II; wherein,

[0052] (Formula I);

[0053] (Formula II);

[0054] According to the deviation Δρ of the average density of the samples at the upper, middle, and lower positions and the deviation ΔR result of the average asphalt volume usage, the mixing uniformity of the asphalt mixture containing steelmaking slag is judged according to the following method:

[0055] When Δρ ≤ 0.2 g / cm 3 and ΔR ≤ 0.01 g / cm 3 the mixture is evenly mixed;

[0056] When Δρ > 0.2 g / cm 3 or ΔR > 0.01 g / cm 3 the mixture is not evenly mixed.

[0057] In some examples of the present invention, the combustion can be carried out at 530 ± 10 °C for 60 - 70 min.

[0058] The technical solutions of the present invention will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0059] As Figure 1 shown, the magnetic stirring device of the present invention includes a feed inlet 1, a discharge outlet 9, and electromagnets 3 symmetrically arranged on the inner top wall 2 of the magnetic stirring device; stirring devices are arranged on both inner side walls of the magnetic stirring device, and the stirring device includes a stirring shaft 5. A fixed tooth shaft 7 is fixed on the stirring shaft 5, and stirring teeth 4 with two long and one short are fixed on the fixed tooth shaft 7. The fixed tooth shaft 7 of one side stirring device is longer than the fixed tooth shaft 7 of the other side stirring device; a discharge baffle 10 is arranged at the discharge outlet 9. In order to facilitate the detection of the uniformity of the mixture, sampling ports 6 are respectively arranged at the upper, middle, and lower positions on one inner side wall of the magnetic stirring device, and each sampling port 6 is provided with a sampling baffle 8.

[0060] In some examples of the present invention, the same volume of steelmaking slag and coarse aggregate can be obtained by the drainage method, specifically:

[0061] In two water-containing containers, steelmaking slag with a particle size of 4.75 - 19 mm and coarse aggregate with a particle size of 4.75 - 19 mm are respectively placed, so that the water level in the container rises or the overflow water volume is the same, and the same volume of steelmaking slag and coarse aggregate can be obtained.

[0062] In some examples of the present invention, the method for obtaining the balanced current includes the following steps:

[0063] Put the steel-making waste slag into container A, put the coarse aggregate into container B, and hang container A and container B under the dynamometer respectively; where containers A and B are plastic mesh bags of equal mass.

[0064] Then place container A and container B at the same height inside the magnetic stirring device.

[0065] Connect the power supply of the electromagnet, adjust the current intensity in the electromagnet. When the readings of the two dynamometers hanging the steel-making waste slag and the coarse aggregate are the same, record the current of the electromagnet, which is the balance current.

[0066] In the following specific embodiments, the fine aggregate includes limestone aggregate, basalt aggregate, and diabase aggregate. The particle size is less than 4.75 mm.

[0067] In the following specific embodiments, the mineral powder is obtained by processing and grinding limestone, and the content below 0.075 mm is not less than 75%.

[0068] Example 1

[0069] This embodiment provides a mixing method for the steel-making waste slag asphalt mixture, including the following steps:

[0070] S1. Put steel slag particles and limestone aggregate with a particle size of 9.5 - 13.2 mm into beakers containing 1000 mL of water respectively, so that the water level in the beaker rises by 500 mL, obtaining steel slag particles and limestone aggregate with the same volume; put the steel slag particles and limestone aggregate into plastic mesh bags respectively, and hang the plastic mesh bags under the spring dynamometer.

[0071] S2. Place the steel slag particles and limestone aggregate in step S1 at the same height inside the magnetic stirring device, adjust the current intensity in the electromagnet, so that the readings of the spring dynamometers hanging the steel slag particles and the limestone aggregate are the same, that is, the gravity of the steel slag particles and the limestone aggregate is the same, and record the current in the electromagnet at this time, that is, obtain the balance current.

[0072] S3. Add the steel slag particles and limestone aggregate in step S2 into the magnetic stirring device, add fine aggregate, mineral powder, and asphalt, turn on the electromagnet and maintain the balance current in step S2, and mix for 40 s to obtain the steel-making waste slag asphalt mixture. Among them, by mass percentage, the steel-making waste slag asphalt mixture includes 50% of the mixture of steel-making waste slag and coarse aggregate, 45% of fine aggregate, 3% of mineral powder, and 2% of asphalt.

[0073] This embodiment also provides a method for evaluating the uniformity of the above-mentioned steel-making waste slag asphalt mixture, including the following steps:

[0074] P1. For the well-mixed steel-smelting waste slag asphalt mixture in step S3 of this embodiment, samples are taken at the upper, middle, and lower sampling ports of the magnetic stirring device, weighed, and the masses are obtained as M 0上 = 2151.6 g, M 0中 = 2278.2 g, M 0下 = 2244.3 g;

[0075] P2. Place the samples at the upper, middle, and lower positions in step P1 into an asphalt combustion furnace and burn them at 530 °C for 60 min, then weigh the masses, and the masses are obtained as M 1上 = 2049.1 g, M 1中 = 2169.7 g, M 1下 = 2137.4 g;

[0076] P3. Use the drainage method to measure the volumes of the samples at the upper, middle, and lower positions in step P2, and the volumes are obtained as V 上 = 759.8 cm 3 、V 中 = 758.1 cm 3 、V 下 = 721.1 cm 3 ;

[0077] P4. Calculate the deviation Δρ of the average density of the samples at the upper, middle, and lower positions; calculate the deviation ΔR of the average asphalt volume usage;

[0078]

[0079] P5. In step P4, Δρ = 0.267 g / cm 3 , which is greater than 0.2 g / cm 3 ; in step P4, ΔR = 0.0133 g / cm 3 , which is greater than 0.01 g / cm 3 ; that is, the steel-smelting waste slag asphalt mixture in this embodiment is not evenly mixed.

[0080] At the same time, according to the "Technical Specifications for Construction of Highway Asphalt Pavement" (JTG F40-2004), for the samples taken from the upper, middle, and lower sampling holes in Example 1, the traditional screening method is used to test the mixing uniformity of the asphalt mixture. If one or more key sieve holes do not meet the specification requirements, it is determined as unqualified, that is, the mixing is uneven. The screening results are shown in Table 1.

[0081] Table 1 Screening Results of Samples Sampled from Different Sampling Holes (Mixing for 40 s)

[0082]

[0083] The passing rates of the key sieve holes in Table 1 do not meet the requirements, and the mixture is not evenly mixed. The determination result of the method of the present invention is consistent with that of the traditional specification method.

[0084] Example 2

[0085] The mixing method of the steel slag-containing asphalt mixture in this example is basically the same as that in Example 1, except that: the mixing time in step S3 is 45 s; by mass percentage, the steel slag-containing asphalt mixture includes 60% of the mixture of steel slag and coarse aggregate, 25% of fine aggregate, 10% of mineral powder and 5% of asphalt.

[0086] This example also provides a method for evaluating the uniformity of the above-mentioned steel slag-containing asphalt mixture, including the following steps:

[0087] P1. For the steel slag-containing asphalt mixture mixed well in step S3 of this example, samples are taken at the upper, middle, and lower sampling ports of the magnetic stirring device respectively, weighed, and M 0上 = 2162.3 g, M 0中 = 2289.3 g, M 0下 = 2256.6 g are obtained respectively;

[0088] P2. The samples at the upper, middle, and lower positions in step P1 are placed in an asphalt combustion furnace and burned at 520 °C for 65 min, weighed, and M 1上 = 2056.4 g, M 1中 = 2180.3 g, M 1下 = 2149.1 g are obtained respectively;

[0089] P3. The samples at the upper, middle, and lower positions in step P2 are respectively measured for volume using the drainage method, and V 上 = 755.2 cm 3 , V 中 = 762.6 cm 3 , V 下 = 728.3 cm 3 are obtained respectively;

[0090] P4. Calculate the deviation Δρ of the average density of the samples at the upper, middle, and lower positions; calculate the deviation ΔR of the average asphalt volume usage;

[0091]

[0092] P5. In step P4, Δρ = 0.228 g / cm 3 , which is greater than 0.2 g / cm 3 ; that is, the steel slag-containing asphalt mixture in this example is not evenly mixed.

[0093] Meanwhile, according to the "Technical Specifications for Construction of Highway Asphalt Pavements" (JTG F40 - 2004), for the samples taken from the upper, middle, and lower sampling holes in Example 2 respectively, the traditional screening method was used to inspect the mixing uniformity of the asphalt mixture. If one or more key sieve holes did not meet the specification requirements, it was determined as unqualified, that is, the mixing was uneven. The screening results are shown in Table 2.

[0094] Table 2 Screening Results of Samples Taken from Different Sampling Holes (Mixing for 45 s)

[0095]

[0096] In Table 2, the passing rates of the 9.5 mm and 13.2 mm sieve holes did not meet the requirements, and the mixture was unevenly mixed. The determination result of the method of the present invention was consistent with that of the traditional specification method.

[0097] Example 3

[0098] The mixing method of the steel - making slag - containing asphalt mixture in this example was basically the same as that in Example 1, with the differences being that: in step S3, the mixing time was 50 s; by mass percentage, the steel - making slag - containing asphalt mixture included 29% of the mixture of steel - making slag and coarse aggregate, 65% of fine aggregate, and 6% of asphalt.

[0099] This example also provides a method for evaluating the uniformity of the above - mentioned steel - making slag - containing asphalt mixture, including the following steps:

[0100] P1. For the steel - making slag - containing asphalt mixture mixed well in step S3 of this example, samples were taken from the sampling ports at the upper, middle, and lower positions of the magnetic stirring device, weighed, and M 0上 = 2113.5 g, M 0中 = 2232.4 g, M 0下 = 2293.2 g were obtained respectively;

[0101] P2. The samples at the upper, middle, and lower positions in step P1 were placed in an asphalt combustion furnace and burned at 540 °C for 70 min, then weighed, and M 1上 = 2012.3 g, M 1中 = 2131.2 g, M 1下 = 2173.6 g were obtained respectively;

[0102] P3. The samples at the upper, middle, and lower positions in step P2 were respectively measured for volume using the drainage method, and V 上 = 708.1 cm 3 , V 中 = 741.0 cm 3 , V 下 = 801.2 cm 3 were obtained respectively;

[0103] P4. Calculate the deviation Δρ of the average density of the samples at the upper, middle, and lower positions; calculate the deviation ΔR of the average asphalt volume usage.

[0104]

[0105] P5. In step P4, ΔR = 0.0126 g / cm 3 , which is greater than 0.01 g / cm 3 ; that is, the asphalt mixture containing steel-making slag in this embodiment is not evenly mixed.

[0106] Meanwhile, according to the "Technical Specification for Construction of Highway Asphalt Pavements" (JTG F40 - 2004), for the samples taken from the upper, middle, and lower sampling holes of Example 3 respectively, using the traditional screening method to test the evenness of the asphalt mixture mixing, if one or more key sieve holes do not meet the specification requirements, it is judged as unqualified, that is, the mixing is uneven. The screening results are shown in Table 3.

[0107] Table 3 Screening Results of Samples Sampled from Different Sampling Holes (Mixing for 50 s)

[0108]

[0109] In Table 3, the passing rates of the 4.75 mm and 9.5 mm sieve holes do not meet the requirements, and the mixture is not evenly mixed. The judgment results of the method of the present invention are consistent with those of the traditional specification method.

[0110] Example 4

[0111] The mixing method of the asphalt mixture containing steel-making slag in this embodiment is basically the same as that in Example 1, with the difference that: the mixing time in step S3 is 55 s; by mass percentage, the asphalt mixture containing steel-making slag includes 20% of the mixture of steel-making slag and coarse aggregate, 65% of fine aggregate, 10% of mineral powder, and 5% of asphalt.

[0112] This embodiment also provides the method for evaluating the evenness of the above-mentioned asphalt mixture containing steel-making slag, including the following steps:

[0113] P1. For the asphalt mixture containing steel-making slag mixed well in step S3 of this embodiment, take samples from the sampling ports at the upper, middle, and lower positions of the magnetic stirring device respectively, weigh the masses, and obtain M 0上 = 2135.5 g, M 0中 = 2316.3 g, M 0下 = 2282.6 g respectively;

[0114] P2. Place the samples at the upper, middle, and lower positions in step P1 in an asphalt combustion furnace and burn them at 530 °C for 65 min, weigh the masses, and obtain M 1上 = 2033.2 g, M1中 = 2207.1 g, M 1下 = 2171.8 g;

[0115] P3. Use the drainage method to measure the volumes of the samples at the upper, middle, and lower positions in step P2, and obtain V 上 = 703.5 cm 3 、V 中 = 760.3 cm 3 、V 下 = 776.8 cm 3 ;

[0116] P4. Calculate the deviation Δρ of the average density of the samples at the upper, middle, and lower positions; calculate the deviation ΔR of the average asphalt volume usage;

[0117]

[0118] P5. In step P4, Δρ = 0.107 g / cm 3 , less than 0.2 g / cm 3 ; in step P4, ΔR = 0.0028 g / cm 3 , less than 0.01 g / cm 3 ; that is, the asphalt mixture containing steelmaking slag in this embodiment is not evenly mixed.

[0119] At the same time, according to the "Technical Specifications for Construction of Highway Asphalt Pavements" (JTG F40 - 2004), for the samples taken from the upper, middle, and lower sampling holes in Example 4, the traditional screening method is used to test the mixing uniformity of the asphalt mixture. If one or more key sieve holes do not meet the specification requirements, it is determined as unqualified, that is, the mixing is uneven. The screening results are shown in Table 4.

[0120] Table 4 Screening Results of Samples Sampled from Different Sampling Holes (Mixing for 55 s)

[0121]

[0122] The passing rates of the key sieve holes in Table 4 all meet the requirements, and the mixture is evenly mixed. The determination result of the method of the present invention is consistent with the determination result of the traditional specification method.

[0123] The results of the above Examples 1 - 4 show that the determination result of the uniformity evaluation method of the present invention is consistent with the determination result of the traditional specification method, indicating that the uniformity evaluation method of the present invention is reliable in evaluation. The parameter settings in the uniformity evaluation method of the present invention are accurate and reasonable.

[0124] The above specific embodiments have described the implementation of the present invention in detail. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the claims and technical concept of the present invention, various simple modifications and changes can be made to the technical solution of the present invention, and these simple variations all fall within the protection scope of the present invention.

Claims

1. A mixing method for asphalt mixture containing steelmaking waste residue, characterized in that: The following steps are involved: The same volume of steel waste slag and coarse aggregate are suspended in a magnetic stirring device respectively, and the magnetic field strength of the electromagnet is adjusted so that the steel waste slag and the coarse aggregate are subjected to the same gravity to obtain a balanced current; wherein the electromagnet is located at the upper part of the magnetic stirring device; Adding raw materials including the steelmaking waste slag, the coarse aggregate, the fine aggregate, the mineral powder and the asphalt into the magnetic stirring device, energizing the electromagnet and maintaining the balanced current, and mixing to obtain an asphalt mixture containing the steelmaking waste slag; The method for obtaining the balancing current comprises the following steps: The steelmaking waste slag and coarse aggregate are placed in containers of the same weight, and then the containers are hung under the dynamometer, and the steelmaking waste slag and coarse aggregate are placed at the same height in the magnetic stirring device; The power supply of the electromagnet is turned on, and the current intensity in the electromagnet is adjusted. When the readings of the two dynamometers hanging the steelmaking waste slag and the coarse aggregate are observed to be the same, the current of the electromagnet is recorded as the balance current.

2. The mixing method according to claim 1, characterized in that: The steelmaking waste slag includes at least one of blast furnace ironmaking slag, converter slag, open-hearth slag and electric furnace slag generated in the steel smelting process.

3. The mixing method according to claim 1, characterized in that: The mixing time is not less than 55s.

4. The mixing method according to claim 1, characterized in that: Calculated by weight percentage, the steelmaking waste slag asphalt mixture includes a mixture of 20-60% steelmaking waste slag and coarse aggregate, 25-65% fine aggregate, 0-10% mineral powder and 2-6% asphalt.

5. The mixing method according to claim 1, characterized in that: The particle sizes of the steelmaking waste slag and coarse aggregate are both 4.75-19 mm.

6. The mixing method according to claim 1, characterized in that: A feed port and an electromagnet are provided at the top of the magnetic stirring device, stirring devices are provided on the inner walls on both sides, the stirring device comprises a stirring shaft, a fixed gear shaft and stirring teeth, the fixed gear shaft is fixedly connected to the stirring shaft, a plurality of stirring teeth are fixedly connected to the fixed gear shaft, the fixed gear shaft of the stirring device on one side is longer than the fixed gear shaft of the stirring device on the other side; a discharge baffle and a discharge port are provided at the bottom of the magnetic stirring device.

7. The mixing method according to claim 6, characterized in that: Electromagnets are symmetrically arranged on the upper part of the inner wall of the magnetic stirring device.

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