Magnetic asphalt concrete for electromagnetic induction wireless charging pavement as well as preparation method and application of magnetic asphalt concrete

Abstract

The invention discloses magnetic asphalt concrete for an electromagnetic induction wireless charging pavement as well as a preparation method and application of the magnetic asphalt concrete, and belongs to the field of road engineering materials and road infrastructures. The magnetic asphalt concrete is prepared from the following raw materials in parts by weight: 8 to 12 parts of magnetic micro powder, 5.5 to 6.5 parts of asphalt, 50 to 75 parts of coarse aggregate, 20 to 40 parts of fine aggregate and 0.1 to 0.2 part of coupling agent, wherein the magnetic micro powder is prepared by mixing magnetic separation steel slag and a solid waste admixture, calcining, ball-milling to obtain magnetic coarse powder, mixing with a composite dispersant, and ball-milling at a high speed; the composite dispersing agent is a mixture of triethanolamine, glycerol and oleic acid. The magnetic asphalt concrete has good adhesion performance and pavement performance, can enhance the adhesion and interlayer mechanical strength of an asphalt concrete surface layer and a charging device when being used for a wireless charging pavement, greatly improves the charging efficiency, prolongs the service life of the pavement, and has a good application prospect.

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 popularity of electric vehicles and the booming development of wireless power transmission technology, wireless charging pavement has gradually attracted attention in recent years. Research on wireless charging pavement includes designing pavement structure, burial depth, and selecting appropriate material ratios to meet the long-term driving function of the road and the safe and efficient operation of wireless power transmission.

[0003] Wireless charging technology is based on the resonant inductive coupling process between the primary and secondary coils to achieve contactless power transmission. Theoretically, the transmission efficiency can reach more than 97%. In wireless charging pavement, the primary device needs to be buried in the pavement structure layer, and the pavement structure layer is used to resist the adverse effects of traffic loads and environmental factors. The primary coil is buried in the pavement structure layer, and the magnetic field emitted by the primary coil must first pass through the pavement material layer before it can reach the secondary coil to transmit energy. Conventional pavement materials include asphalt concrete and cement concrete materials, whose electromagnetic properties are very different from those of air. When the wireless power transmission system is paved in the pavement material, the power transmission process will use the pavement material as a medium, which will be affected by its electromagnetic properties, weakening the original magnetic field, and then affecting the wireless charging system, reducing the output power and transmission efficiency of the system. In order to reduce the negative impact of the insertion of pavement materials on the wireless charging system, many studies have used magnetic materials such as magnetite and ferrite powder to modify cement pavement materials to enhance the magnetic conductivity of pavement materials. 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 related to the installation of charging equipment. At present, the optimization methods for magnetic pavements are all based on the overall structure and device innovation optimization, without taking into account the road performance of the pavement, and the construction process is complicated and costly. Summary of the invention

[0005] In view of the above technical problems, the purpose of the present invention is to provide a magnetic asphalt concrete for electromagnetic induction wireless charging pavement and its preparation method and application. 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.

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

[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 steel slag and solid waste admixtures, calcining, ball milling to obtain magnetic coarse powder, and then mixing with a composite dispersant and 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: grinding at a 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 rotation 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) After the magnetic coarse powder and the composite dispersant are evenly mixed, the mixture is subjected to high-speed ball milling at a speed of 500-1000 r / min for 40-60 minutes, and the obtained particles having a particle size of less than 0.075 mm are magnetic micropowders.

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

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

[0022] According to the above scheme, 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 the fine aggregate are mixed evenly, asphalt is added and mixed, and finally the magnetic micro powder and the 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: the 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 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 compounding them by ball milling; wherein:

[0030] High-temperature calcination of steel slag and solid waste admixtures can reduce the metal oxides (Fe2O3, MgO, Al2O3) of the steel slag, greatly increasing its magnetism; and 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, which can enhance the adhesion with weakly acidic asphalt as fillers for asphalt concrete, 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 the hard agglomeration of the powder, and 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, and the surface of the magnetic micropowder is modified to reduce magnetic agglomeration, so as to achieve 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 and ball milling them, and has good magnetic properties, is evenly and stably dispersed in concrete, effectively enhances the magnetic permeability of asphalt concrete, reduces the interference of traditional pavement materials on the wireless charging magnetic field, and improves the wireless charging efficiency; the magnetic micropowder has good adhesion performance, and is added to asphalt concrete with a coupling agent to make the concrete more compact 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 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 particle size of the coarse aggregate is 2.36-16 mm, and the particle size of the fine aggregate 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 2h; the calcined product cooled to room temperature is placed in a horizontal ball mill and ball-milled at a speed of 250r / min for 60 minutes to obtain a magnetic coarse powder; the magnetic coarse powder and the composite dispersant are evenly mixed and poured into a ball milling jar filled with steel balls and sealed, and placed on a ball mill for ball milling. After high-speed ball milling at a speed of 800r / min for 45 minutes, the particles with a particle size of less than 0.075mm are obtained, which are magnetic micropowders and are stored in a sealed bag; wherein:

[0038] The composite dispersant is prepared by mixing triethanolamine, propylene glycol 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, and is formed by a planar spiral winding of a Litz wire with a diameter of 5 mm, with 20 turns, and 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, measured 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 the fine aggregate are evenly mixed, add the asphalt and mix for 60 seconds, and finally add the magnetic powder and coupling agent and mix for 60 seconds to obtain magnetic asphalt concrete.

[0043] The obtained magnetic asphalt concrete was spread on the upper layer of the wireless charging unit coil to obtain a wireless charging pavement. After the wireless charging pavement was completed, the relative magnetic permeability of the magnetic asphalt concrete was tested, and the charging efficiency at 10cm and 20cm spacing was tested using the wireless charging unit receiving coil and load. The specific results are shown in Table 1; and the road performance of the magnetic asphalt concrete was tested by sampling. The specific 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, measured 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 the fine aggregate are evenly mixed, add the asphalt and mix for 60 seconds, and finally add the magnetic powder and coupling agent and mix for 60 seconds to obtain magnetic asphalt concrete.

[0047] The obtained magnetic asphalt concrete was spread on the upper layer of the wireless charging unit coil to obtain a wireless charging pavement. After the wireless charging pavement was completed, the relative magnetic permeability of the magnetic asphalt concrete was tested, and the charging efficiency at 10cm and 20cm spacing was tested using the wireless charging unit receiving coil and load. The specific results are shown in Table 1; and the road performance of the magnetic asphalt concrete was tested by sampling. The specific 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, measured 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 the fine aggregate are evenly mixed, add the asphalt and mix for 60 seconds, and finally add the magnetic powder and coupling agent and mix for 60 seconds to obtain magnetic asphalt concrete.

[0051] It was spread on the upper layer of the wireless charging unit coil to obtain a wireless charging pavement. After the wireless charging pavement was completed, the relative magnetic permeability of the magnetic asphalt concrete was tested, and the charging efficiency at 10cm and 20cm spacing was tested using the wireless charging unit receiving coil and load. The specific results are shown in Table 1; and the road performance of the magnetic asphalt concrete was tested by sampling. The specific results are shown in Table 2.

[0052] Comparative Example 1 (Using Ordinary Filler)

[0053] The asphalt concrete of this comparative example includes the following components by weight: 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 uses limestone common filler.

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

[0055] The asphalt concrete of this comparative example includes 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 includes the following components by mass: 10 parts of magnetic mineral 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 no dispersant is added during the ball milling process of the magnetic mineral powder.

[0058] Comparative Example 4 (Using conventional dispersant)

[0059] The asphalt concrete of this comparative example includes the following components by mass: 10 parts of magnetic mineral 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 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 obtained from Examples 1-3 and Comparative Examples 1-4

[0064]

[0065] Through the schemes of Examples 1-3, it can be seen that the magnetic asphalt concrete of the present invention can increase the charging efficiency of the wireless charging pavement while improving its mechanical properties. The charging efficiency at a 10cm spacing is greater than 90%, and the charging efficiency at a 20cm spacing is greater than 80%. As the amount of magnetic micropowder increases, the charging efficiency increases. The magnetic asphalt concrete can stably improve the charging efficiency of the wireless charging system and the road performance of the pavement.

[0066] By comparing Example 2 with Comparative Example 1, it can be seen that the relative magnetic permeability of conventional asphalt concrete is relatively low, which weakens the original magnetic field, thereby affecting the wireless charging system and reducing the output power and transmission efficiency of the system. The magnetic permeability of the magnetic asphalt concrete prepared by the magnetic micropowder of the present invention is increased by more than 2 times, which can reduce the interference of traditional pavement materials on the wireless charging magnetic field, greatly improve the transmission of electromagnetic energy, and thus improve the 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 magnetic properties.

[0068] By comparing Example 2 with Comparative Examples 3 and 4, it can be seen that if no composite dispersant is added during the grinding process of magnetic micropowder, the adhesion between magnetic micropowder and asphalt is poor, which will greatly reduce the road performance, reduce the interlayer shear strength by 46%, and reduce the fatigue life by more than 50%. However, the magnetic micropowder of the present invention is surface modified by composite dispersant micropowder, which can achieve the purpose of uniform and stable dispersion while improving the adhesion of the contact interface between the road material and the charging element.

[0069] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes. 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: By weight, the raw materials include: 8-12 parts of magnetic powder, 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 steel slag and solid waste admixtures, calcining, ball milling to obtain magnetic coarse powder, and then mixing with a composite dispersant and 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, propylene glycol 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. Application 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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