Magnetic asphalt concrete for electromagnetic induction wireless charging pavement and its preparation method and application

Abstract

The present invention discloses a magnetic asphalt concrete for electromagnetic induction wireless charging pavement, its preparation method and application, and belongs to the field of road engineering materials and road infrastructure. The magnetic asphalt concrete comprises, by weight, 8-12 parts of magnetic micropowder, 5.5-6.5 parts of asphalt, 50-75 parts of coarse aggregate, 20-40 parts of fine aggregate, and 0.1-0.2 parts of coupling agent; wherein: the magnetic micropowder is prepared by mixing magnetic separation steel slag and solid waste admixture, calcining, and then ball-milling to obtain magnetic coarse powder, which is then mixed with a composite dispersant and then high-speed ball-milled; the composite dispersant is a mixture of triethanolamine, glycerol and oleic acid. The magnetic asphalt concrete has good adhesion and road performance. When used in wireless charging pavement, it can enhance the adhesion between the asphalt concrete surface layer and the charging device and the interlayer mechanical strength, greatly improve the charging efficiency, and extend the service life of the pavement, with good application prospects.

Description

Technical Field

[0001] The present invention belongs to the field of road engineering materials and road infrastructure, and specifically relates to a magnetic asphalt concrete for electromagnetic induction wireless charging pavement, and a preparation method and application thereof. Background Art

[0002] With the increasing popularity of electric vehicles and the rapid development of wireless power transmission technology, wireless charging pavements have gained increasing attention in recent years. Research on wireless charging pavements involves designing pavement structure, embedding depth, and selecting the appropriate material mix to ensure long-term road performance and the safe and efficient operation of wireless power transmission.

[0003] Wireless charging technology achieves contactless power transmission based on resonant inductive coupling between primary and secondary coils. Theoretically, transmission efficiency can reach over 97%. In wireless charging pavement systems, the primary device must be embedded within the pavement structure, which provides protection against the adverse effects of traffic loads and environmental factors. The primary coil is embedded within the pavement structure, and the magnetic field emitted by it must first pass through the pavement material before reaching the secondary coil for energy transfer. Conventional pavement materials, such as asphalt concrete and cement concrete, have electromagnetic properties significantly different from those of air. When a wireless power transmission system is installed within the pavement material, the power transmission process uses the pavement material as a medium, which is affected by its electromagnetic properties, weakening the primary magnetic field. This, in turn, affects the wireless charging system, reducing its output power and transmission efficiency. To mitigate the negative impact of the pavement material on wireless charging systems, many studies have modified the cement pavement material with magnetic materials such as magnetite and ferrite powder to enhance its magnetic permeability. However, the pavements it is used on are all based on cement concrete. Currently, asphalt concrete is the most widely used high-grade pavement material, and there are few magnetic modification technologies for asphalt concrete. Therefore, the applicability of existing research is poor.

[0004] Patent CN117385699A discloses a magnetic asphalt pavement paving device and paving method for assisted driving, which uses prefabricated magnetic units to assist driving; Patent CN115807369A discloses a magnetized pavement structure and wireless charging device for electric vehicles, which uses new pavement structures and devices to improve transmission power and efficiency. Since the layout and installation of wireless charging equipment may have a certain impact on the pavement structure, such as pavement cracking, structural weakening and other problems, the selected pavement material should have sufficient mechanical strength to withstand conventional traffic loads and additional loads associated with the installation of charging equipment. The current optimization methods for magnetic pavements all use innovative optimization of the overall structure and device, without taking into account the road performance of the pavement, and the construction process is complex and costly. Summary of the Invention

[0005] To address the above technical issues, the present invention aims to provide a magnetic asphalt concrete for electromagnetic induction wireless charging pavement, as well as its preparation method and application. This magnetic asphalt concrete exhibits excellent adhesion and road performance. Its use in wireless charging pavements can enhance the adhesion between the asphalt concrete surface layer and the charging device, as well as the mechanical strength between the layers. This significantly improves charging efficiency and extends the pavement's service life.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] Provided is a magnetic asphalt concrete for electromagnetic induction wireless charging pavement, wherein the raw materials include, by weight: 8-12 parts of magnetic micropowder, 5.5-6.5 parts of asphalt, 50-75 parts of coarse aggregate, 20-40 parts of fine aggregate, and 0.1-0.2 parts of coupling agent; wherein:

[0008] The magnetic fine powder is prepared by mixing magnetic separation steel slag and solid waste admixtures, calcining them, and then ball milling them to obtain magnetic coarse powder, which is then mixed with a composite dispersant and then subjected to high-speed ball milling; the composite dispersant is a mixture of triethanolamine, glycerol and oleic acid.

[0009] According to the above scheme, the mass ratio of steel slag to solid waste admixture is 4:0.5-2; the mass of the composite dispersant accounts for 0.2-0.8% of the mass of the steel slag.

[0010] According to the above scheme, in the composite dispersant, the mass ratio of triethanolamine, glycerol and oleic acid is 2-4:1-2:1.

[0011] According to the above scheme, the ball milling process for obtaining the magnetic coarse powder is as follows: grinding at a rotation speed of 200-300 r / min for 60-90 minutes.

[0012] According to the above scheme, the high-speed ball milling process is: high-speed ball milling at a speed of 500-1000r / min for 40-60min.

[0013] According to the above scheme, the mixed calcination process of magnetic separation steel slag and solid waste admixture is: mix the magnetic separation steel slag and solid waste admixture evenly, and calcine at 500-700°C for 2-4 hours.

[0014] According to the above solution, the particle size of the magnetic micropowder is less than 0.075 mm.

[0015] According to the above scheme, the solid waste admixture is one or more of tailings, fly ash, kaolin, and metakaolin.

[0016] According to the above scheme, the preparation of the magnetic micropowder includes the following steps:

[0017] 1) The magnetically separated steel slag is mixed evenly with the solid waste admixture, and then calcined at 500-700°C for 2-4 hours;

[0018] 2) Grinding the calcined product cooled to room temperature at a speed of 200-300 r / min for 60-90 minutes to obtain a coarse magnetic powder;

[0019] 3) The magnetic coarse powder and the composite dispersant are evenly mixed and then subjected to high-speed ball milling at a speed of 500-1000 r / min for 40-60 minutes. The obtained particles with a particle size of less than 0.075 mm are magnetic fine powder.

[0020] According to the above solution, the asphalt is one or more of road petroleum asphalt or modified asphalt.

[0021] According to the above solution, the coarse aggregate or fine aggregate is one or more of basalt, limestone, and limestone, wherein the particle size of the coarse aggregate is ≥2.36 mm, and the particle size of the fine aggregate is ≤2.36 mm.

[0022] According to the above solution, the coupling agent is one or more of organic chromium complexes, silanes, titanates and aluminate compounds.

[0023] The present invention also provides a method for preparing the magnetic asphalt concrete, comprising the following steps:

[0024] 1) Heat the asphalt to 160-170°C, and heat the coarse aggregate, fine aggregate and magnetic powder to 175-185°C respectively;

[0025] 2) After the coarse aggregate and fine aggregate are mixed evenly, asphalt is added and mixed, and finally magnetic micropowder and coupling agent are added and mixed evenly to obtain magnetic asphalt concrete.

[0026] According to the above scheme, in step 2), the mixing time is 60-90s.

[0027] Provided is an application of the magnetic asphalt concrete in an electromagnetic induction wireless charging pavement.

[0028] According to the above scheme, the specific application is: its magnetic asphalt concrete is spread on the upper layer of the wireless charging unit coil to obtain a wireless charging pavement.

[0029] The present invention provides a magnetic asphalt concrete for electromagnetic induction wireless charging pavement, comprising magnetic micropowder, asphalt, coarse aggregate, fine aggregate and a coupling agent; the magnetic micropowder is prepared by calcining steel slag and solid waste admixtures, initially grinding them, and then adding a composite dispersant and then ball milling them; wherein:

[0030] High-temperature calcination of steel slag and solid waste admixtures can reduce the metal oxides (Fe2O3, MgO, Al2O3) in the steel slag, significantly increasing its magnetism. The dense oxide network system of the solid waste admixture can isolate the air, protect the internal magnetic material from oxidation, and increase its durability. At the same time, the products of calcined steel slag and solid waste admixtures contain a large amount of alkaline substances such as CaO. As fillers in asphalt concrete, they can enhance adhesion to weakly acidic asphalt, improve the overall performance of asphalt concrete, and enhance the adhesion of the contact interface between the pavement material and the charging element. In addition, the steel slag and admixtures are first coarsely ground after calcination to reduce hard agglomeration of the powder. Then, a specially selected composite dispersant is added for high-speed ball milling, so that the composite dispersant is evenly distributed on the surface of the magnetic micropowder. The surface of the magnetic micropowder is modified to reduce magnetic agglomeration, achieving the purpose of uniform and stable dispersion of the magnetic micropowder in the asphalt concrete.

[0031] The beneficial effects of the present invention are:

[0032] 1. The present invention provides a magnetic asphalt concrete for electromagnetic induction wireless charging pavement, comprising magnetic micropowder, asphalt, coarse aggregate, fine aggregate and a coupling agent; wherein the magnetic micropowder is made by calcining steel slag and solid waste admixtures, initially grinding them, and then adding a composite dispersant and compounding them for ball milling. The magnetic micropowder has good magnetic properties and is evenly and stably dispersed in concrete, effectively enhancing the magnetic permeability of the asphalt concrete, reducing the interference of traditional pavement materials on the wireless charging magnetic field, and improving the wireless charging efficiency; the magnetic micropowder has good adhesion performance and is added to the asphalt concrete with a coupling agent to make the concrete more dense and the surface energy of the asphalt mortar larger, thereby improving the road performance of the asphalt concrete, enhancing the adhesion between the asphalt concrete surface layer and the charging device and the interlayer mechanical strength, and extending the service life of the wireless charging pavement, and has important application prospects.

[0033] 2. The preparation process of the present invention is simple, and the raw materials used are solid waste materials such as steel slag and solid waste admixtures, which makes high-value use of solid waste resources, is low-carbon and environmentally friendly, and has low cost, which is conducive to industrial promotion and application. DETAILED DESCRIPTION

[0034] In order to further disclose but not limit the present invention, the present invention is further described in detail below with reference to examples.

[0035] The aggregate used in the following examples is basalt; the coarse aggregate particle size is 2.36-16 mm, and the fine aggregate particle size is 0-2.36 mm; the asphalt is SBS ID modified asphalt; and the coupling agent is silane coupling agent KH550.

[0036] The preparation process of the magnetic micropowder used in the following examples is as follows:

[0037] The steel slag after magnetic separation and the solid waste admixture are mixed in a mass ratio of 4:1, and then calcined at 500°C for 2 hours; the calcined product cooled to room temperature is placed in a horizontal ball mill and ball-milled at a speed of 250 r / min for 60 minutes to obtain a magnetic coarse powder; the magnetic coarse powder is uniformly mixed with a composite dispersant, poured into a ball mill jar filled with steel balls, sealed, and placed on a ball mill for ball milling. After high-speed ball milling at a speed of 800 r / min for 45 minutes, the obtained particles with a particle size of less than 0.075 mm are magnetic fine powders, which are stored in a sealed bag; wherein:

[0038] The composite dispersant is prepared by mixing triethanolamine, glycerol and oleic acid in a ratio of 2:1:1 and stirring at 800 r / min for 10 minutes. The amount of the composite dispersant is 0.5% of the mass of the steel slag.

[0039] The wireless charging coil structure in the wireless charging unit used in the following embodiments is rectangular, made of a flat spiral wound Litz wire with a diameter of 5 mm, wound 20 times, and has a size of 300×300×5 mm. 3 .

[0040] Example 1

[0041] The magnetic asphalt concrete for electromagnetic induction wireless charging pavement of this embodiment includes the following components, calculated by mass: 8 parts of magnetic micropowder, 5.5 parts of SBS modified asphalt, 52 parts of coarse aggregate, 40 parts of fine aggregate, and 0.15 parts of coupling agent.

[0042] Heat the asphalt to 165°C, and heat the aggregate and magnetic powder to 180°C respectively; after the coarse aggregate and fine aggregate are evenly mixed, add asphalt and mix for 60 seconds, and finally add magnetic powder and coupling agent and mix for 60 seconds to obtain magnetic asphalt concrete.

[0043] The resulting magnetic asphalt concrete was paved on top of the wireless charging unit coils to create a wireless charging pavement. After the wireless charging pavement was completed, the relative magnetic permeability of the magnetic asphalt concrete was tested. The charging efficiency at 10cm and 20cm distances was tested using the wireless charging unit receiving coil and load. The results are shown in Table 1. Samples were also taken to test the road performance of the magnetic asphalt concrete. The results are shown in Table 2.

[0044] Example 2

[0045] The magnetic asphalt concrete for electromagnetic induction wireless charging pavement of this embodiment includes the following components, calculated by mass: 10 parts of magnetic micropowder, 6 parts of SBS modified asphalt, 60 parts of coarse aggregate, 30 parts of fine aggregate, and 0.15 parts of coupling agent.

[0046] Heat the asphalt to 165°C, and heat the aggregate and magnetic powder to 180°C respectively; after the coarse aggregate and fine aggregate are evenly mixed, add asphalt and mix for 60 seconds, and finally add magnetic powder and coupling agent and mix for 60 seconds to obtain magnetic asphalt concrete.

[0047] The resulting magnetic asphalt concrete was paved on top of the wireless charging unit coils to create a wireless charging pavement. After the wireless charging pavement was completed, the relative magnetic permeability of the magnetic asphalt concrete was tested. The charging efficiency at 10cm and 20cm distances was tested using the wireless charging unit receiving coil and load. The results are shown in Table 1. Samples were also taken to test the road performance of the magnetic asphalt concrete. The results are shown in Table 2.

[0048] Example 3

[0049] The magnetic asphalt concrete for electromagnetic induction wireless charging pavement of this embodiment includes the following components, calculated by mass: 12 parts of magnetic micropowder, 6.5 parts of SBS modified asphalt, 68 parts of coarse aggregate, 20 parts of fine aggregate, and 0.2 parts of coupling agent.

[0050] Heat the asphalt to 165°C, and heat the aggregate and magnetic powder to 180°C respectively; after the coarse aggregate and fine aggregate are evenly mixed, add asphalt and mix for 60 seconds, and finally add magnetic powder and coupling agent and mix for 60 seconds to obtain magnetic asphalt concrete.

[0051] It was then paved on top of the wireless charging unit coil to create a wireless charging pavement. After the wireless charging pavement was completed, the relative magnetic permeability of the magnetic asphalt concrete was tested. The charging efficiency at 10cm and 20cm spacings was tested using the wireless charging unit receiving coil and load. The results are shown in Table 1. Samples were also taken to test the road performance of the magnetic asphalt concrete. The results are shown in Table 2.

[0052] Comparative Example 1 (using ordinary filler)

[0053] The asphalt concrete of this comparative example comprises the following components by mass: 10 parts of common filler, 6 parts of SBS modified asphalt, 60 parts of coarse aggregate, 30 parts of fine aggregate, and 0.15 parts of coupling agent. The specific steps are the same as those of Example 2, except that the mineral powder is limestone common filler.

[0054] Comparative Example 2 (Using Steel Slag Magnetic Powder)

[0055] The asphalt concrete of this comparative example comprises the following components by mass: 10 parts of steel slag magnetic powder, 6 parts of SBS modified asphalt, 60 parts of coarse aggregate, 30 parts of fine aggregate, and 0.15 parts of coupling agent. The specific steps are the same as those of Example 2, except that the mineral powder is steel slag magnetic powder.

[0056] Comparative Example 3 (without adding dispersant)

[0057] The asphalt concrete of this comparative example comprises the following components, calculated by mass: 10 parts magnetic mineral powder, 6 parts SBS modified asphalt, 60 parts coarse aggregate, 30 parts fine aggregate, and 0.15 parts coupling agent. The specific steps are the same as those of Example 2, except that no dispersant is added during the ball milling of the magnetic mineral powder.

[0058] Comparative Example 4 (using conventional dispersant)

[0059] The asphalt concrete of this comparative example comprises the following components, calculated by mass: 10 parts magnetic mineral powder, 6 parts SBS modified asphalt, 60 parts coarse aggregate, 30 parts fine aggregate, and 0.15 parts coupling agent. The specific steps are the same as those of Example 2, except that a conventional dispersant (triethanolamine) is used instead of a composite dispersant during the ball milling of the magnetic mineral powder.

[0060] Table 1. Magnetic permeability and charging efficiency of asphalt concrete obtained in Examples 1-3 and Comparative Examples 1-4

[0061]

[0062]

[0063] Table 2. Road performance of asphalt concrete prepared from Examples 1-3 and Comparative Examples 1-4

[0064]

[0065] As demonstrated in Examples 1-3, the magnetic asphalt concrete of the present invention can improve both its mechanical properties and the charging efficiency of wireless charging pavement. The charging efficiency is greater than 90% at a 10cm spacing and greater than 80% at a 20cm spacing. The efficiency increases with increasing magnetic micropowder content, demonstrating that magnetic asphalt concrete can steadily improve both the charging efficiency of wireless charging systems and the pavement's performance.

[0066] A comparison of Example 2 and Comparative Example 1 shows that conventional asphalt concrete has a low relative magnetic permeability, which weakens the original magnetic field, thereby affecting the wireless charging system and reducing the system's output power and transmission efficiency. The magnetic asphalt concrete prepared with the magnetic micropowder of the present invention has a magnetic permeability that is more than doubled, reducing the interference of traditional pavement materials with the wireless charging magnetic field, significantly improving the transmission of electromagnetic energy, and thus improving charging efficiency.

[0067] By comparing Example 2 with Comparative Example 2, it can be seen that due to the poor dispersibility of ordinary steel slag magnetic powder, it is easy to agglomerate in concrete, resulting in a significant reduction in the road performance of asphalt concrete and little improvement in magnetism.

[0068] A comparison of Example 2 with Comparative Examples 3 and 4 shows that without the addition of a composite dispersant during the grinding process, the adhesion between the magnetic micropowder and asphalt is poor, significantly reducing road performance, with interlayer shear strength reduced by 46% and fatigue life reduced by over 50%. However, the magnetic micropowder of the present invention, surface-modified with a composite dispersant, achieves uniform and stable dispersion while also improving adhesion at the interface between the pavement material and the charging element.

[0069] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and implementation methods. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to specific details.

Claims

1. A magnetic asphalt concrete for electromagnetic induction wireless charging pavement, characterized in that: The raw materials include, by weight: 8-12 parts of magnetic micropowder, 5.5-6.5 parts of asphalt, 50-75 parts of coarse aggregate, 20-40 parts of fine aggregate, and 0.1-0.2 parts of coupling agent; wherein: The magnetic fine powder is prepared by mixing magnetic separation steel slag and solid waste admixtures, calcining them, and then ball milling them to obtain magnetic coarse powder, which is then mixed with a composite dispersant and then subjected to high-speed ball milling; the composite dispersant is a mixture of triethanolamine, glycerol and oleic acid.

2. The magnetic asphalt concrete according to claim 1, characterized in that The mass ratio of steel slag to solid waste admixture is 4:0.5-2; the composite dispersant accounts for 0.2-0.8% of the mass of the steel slag.

3. The magnetic asphalt concrete according to claim 1, characterized in that In the composite dispersant, the mass ratio of triethanolamine, glycerol and oleic acid is 2-4:1-2:

1.

4. The magnetic asphalt concrete according to claim 1, characterized in that The high-speed ball milling process is: ball milling at a speed of 500-1000r / min for 40-60min.

5. The magnetic asphalt concrete according to claim 1, characterized in that: The mixed calcination process of magnetic separation steel slag and solid waste admixture is: calcination at 500-700℃ for 2-4 hours.

6. The magnetic asphalt concrete according to claim 1, characterized in that: The solid waste admixture is one or more of tailings, fly ash, kaolin, and metakaolin.

7. The magnetic asphalt concrete according to claim 1, characterized in that: The asphalt is one or more of road petroleum asphalt or modified asphalt; the coupling agent is one or more of organic chromium complexes, silanes, titanates and aluminate compounds.

8. The magnetic asphalt concrete according to claim 1, characterized in that: The coarse aggregate or fine aggregate is one or more of basalt, limestone, and limestone, wherein the particle size of the coarse aggregate is ≥2.36 mm, and the particle size of the fine aggregate is ≤2.36 mm.

9. A method for preparing magnetic asphalt concrete according to any one of claims 1 to 8, characterized in that: The following steps are involved: 1) Heat the asphalt to 160-170°C, and heat the coarse aggregate, fine aggregate and magnetic powder to 175-185°C respectively; 2) After the coarse aggregate and fine aggregate are mixed evenly, asphalt is added and mixed, and finally magnetic micropowder and coupling agent are added and mixed evenly to obtain magnetic asphalt concrete.

10. Use of the magnetic asphalt concrete according to any one of claims 1 to 8 in an electromagnetic induction wireless charging pavement.

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