JP2023108416A - pavement structure - Google Patents

Abstract

To provide a pavement structure excellent in workability and durability and capable of continuously taking out power from an environment such as facility infrastructure.SOLUTION: A pavement structure 1 is a pavement structure in which a roadbed layer 2 and a road surface layer 3 supported by the roadbed layer 2 are installed. The roadbed layer 2 includes a lamination part 80 formed by laminating unit structures 81 having voids, and a box-shaped device part 10. The device part 10 has at least one of a tertiary battery part 30 for generating power by the temperature change of an electrode, and a thermoelectric conversion cell part 20 for generating power by a temperature difference between the electrodes.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to a pavement structure capable of supplying electric power with a power generating device that utilizes the temperature in the environment such as facility infrastructure.

Conventionally, facilities such as infrastructure include ancillary facilities that require electric power, such as lighting and signals. For example, on roads, technology for interconnecting various types of equipment is being developed in recent efforts toward intelligent transport systems (ITS), and various types of equipment installed around roads also require electric power. Patent Literature 1 describes a paved road equipped with a device that generates electricity based on a temperature difference in order to supply power to these incidental facilities and various types of equipment.

JP 2005-264558 A

The power generating device of Patent Document 1 uses thermoelectric conversion elements such as Bi—Te system. A thermoelectric conversion element, which is a thin member, is installed parallel to the road surface, and a large number of plate-like heat-conducting members are provided above and below the thermoelectric conversion element. In order to bury a device with many protruding plate-shaped members, special procedures and processes are required for construction, and it is expected that the time and cost required for construction will become a problem when constructing over a wide area. be done. Moreover, it is expected that the plate-shaped heat-conducting member will be disadvantageous in terms of durability against traffic loads. In addition to using the temperature difference, if other power generating means can be used together, the power generating means will complement each other, and the power supply can be stabilized.
The present invention was made in order to solve such problems, and aims to provide a pavement structure that is excellent in workability and durability, and that can sustainably extract power from the environment such as facility infrastructure. do.

In order to solve such problems, a pavement structure according to the present invention is a pavement structure in which a roadbed layer and a road surface layer supported by the roadbed layer are installed, wherein the roadbed layer is a unit structure having voids. A lamination part formed by stacking bodies and a box-shaped device part are provided, and the device part includes a tertiary battery part that generates power according to temperature changes of the electrodes and a thermoelectric conversion cell part that generates power according to the temperature difference between the electrodes. have at least one of

ADVANTAGE OF THE INVENTION According to this invention, it is excellent in workability and durability, and can provide the pavement structure which can extract electric power sustainably from environments, such as a facility infrastructure.

1 is a schematic diagram showing an installation example of a pavement structure according to the present invention; FIG. BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which illustrates the outline of the pavement structure which concerns on this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view which illustrates the outline of the thermoelectric conversion cell which concerns on this invention. FIG. 10 is a perspective view illustrating a modification of the electrodes of the thermoelectric conversion cell; 1 is a perspective view illustrating an outline of a tertiary battery cell according to the present invention; FIG. 1 is a block diagram showing an example of the configuration of an apparatus section according to the present invention; FIG.

An embodiment of the present invention will be described with reference to the drawings. The pavement structure 1 according to the present invention can be widely used for pavement of facility infrastructure such as sidewalks and roadways, as well as parks, commercial facilities, station plazas, harbor facilities, and the like.
As an example is shown in FIG. 1, the pavement structure 1 includes a roadbed layer 2 and a road surface layer 3, and is installed above the ground 100 so that the upper surface of the road surface layer 3 is exposed to the ground surface at the height of the ground 200. It is A base layer 4 may be provided between the pavement structure 1 and the ground 100 .

(base course layer)
The roadbed layer 2 is a structure that supports the road surface layer 3 . As an example is shown in FIG. 2, the roadbed layer 2 includes a device section 10 and a laminated section 80. The laminated section 80 supports the road surface layer 3 and secures a space in which the device section 10 is installed.

(Equipment part)
The device section 10 is a box-shaped member having an electrical device for power generation or the like inside. The device section 10 has a waterproof performance to prevent water or the like from entering into the interior, so that even if the pavement structure 1 is submerged due to, for example, a large amount of rain, it is possible to suppress failure of internal electrical devices. In addition, the device section 10 can protect internal electrical devices from external shocks and the like.
The device section 10 has a thermoelectric conversion cell section 20 , a tertiary battery section 30 , a power storage section 40 and a control section 50 .

(Thermoelectric conversion cell part)
The thermoelectric conversion cell unit 20 is a device that has a thermoelectric conversion cell 21 that uses a solution and that can generate electricity by a temperature difference between the electrodes of the thermoelectric conversion cell 21 . The solution is a given electrolyte solution. The electrolyte solution uses water or an organic compound as a solvent.
The thermoelectric conversion cell 21 can generate electric power, for example, by utilizing the difference in equilibrium potential in the oxidation-reduction reaction. As an example is shown in FIG. 3A, the thermoelectric conversion cell 21 has the electrodes 22 spaced apart from each other in a housing 26 filled with an electrolytic solution 25 . Here, two electrodes 22A and 22B are arranged separately at both ends of the thermoelectric conversion cell 21 . Films 231 and 232 made of a predetermined material are formed on the surfaces of the electrodes 22A and 22B. Membranes 231, 232 may be of the same material. An electric wire 75 and a heat conducting member 70, which will be described later, are connected to the electrodes 22A and 22B.
The thermoelectric conversion cell 21 generates an electromotive force due to a temperature difference between electrodes. The electromotive force of the thermoelectric conversion cell 21 can be about 60 mV if the temperature difference between the electrodes 22A and 22B is about 40° C., for example. The thermoelectric conversion cell section 20 can have a plurality of thermoelectric conversion cells 21 connected in series. The number of cells to be connected in series is not particularly limited. For example, by connecting 20 to 30 thermoelectric conversion cells 21 in series, an electromotive force of about 1.5 V can be obtained. The thermoelectric conversion cells 21 may be connected in parallel, or may be connected in parallel and connected in series.

The thermoelectric conversion cell unit 20 can increase the amount of power generation as the temperature difference between the electrodes 22A and 22B increases. If the thermal conductivity of the material provided between the electrodes is high, the temperature difference is less likely to occur. For example, in a thermoelectric conversion element using a semiconductor material, since the thermal conductivity of the semiconductor material is as high as several hundred W/m·K, it is difficult for the temperature difference to occur between the electrodes. On the other hand, water, which is the material of the solution used in the thermoelectric conversion cell unit 20, is 0.6 W/m·K, and the organic solvent is 0.2 to 0.3 W/m·K. It is smaller than 1 to 2 W/m·K of asphalt and concrete, which are road materials. Since the pavement structure 1 has the thermoelectric conversion cell unit 20 using a solution, the thermal conductivity of the thermoelectric conversion cell 21 can be reduced, and the temperature difference caused by the environment in which the pavement structure 1 is installed can be reduced. Effective utilization can be planned.

(Heat conduction member)
The heat-conducting member 70 has one end as a base end portion 71 and the other end as a tip portion 72 , and serves as a heat conduction path between the base end portion 71 and the tip portion 72 . The heat-conducting member 70 may be formed by forming a wire rod having a large cross-sectional area from a metal having a high thermal conductivity such as copper or aluminum, and covering the wire rod with a heat insulating material such as glass wool. Also, the thermally conductive member 70 can be formed of a resin or the like in which a substance having a high thermal conductivity processed into powder or fiber is dispersed.
In the heat conducting member 70 connected to the thermoelectric conversion cell 21, the base end portion 71 is connected to the electrodes 22A and 22B. The tip portion 72 is arranged on the road surface layer 3 which will be described later. The distal end portion 72 of the heat conducting member 70 connecting the base end portion 71 to the electrode 22A and the distal end portion 72 of the heat conducting member 70 connecting the base end portion 71 to the electrode 22B are arranged at positions where the temperature difference is large. is preferred.
The proximal end 71 may be connected to a wall formed of a material having a high thermal conductivity, for example, adjacent to the electrodes 22A and 22B.

(Tertiary battery part)
The tertiary battery unit 30 is a device that has a tertiary battery cell 31 that uses a solution, and that can generate power according to temperature changes in the electrodes of the tertiary battery cell 31 .
The tertiary battery cell 31 can generate electric power, for example, by utilizing a difference in temperature coefficient of electrode potential between electrodes. As an example is shown in FIG. 4, a tertiary battery cell 31 is configured by arranging an electrode 32 and a separator 34 separating the electrodes 32 in a housing 36 filled with an electrolytic solution 35. . Here, two electrodes 32A and 32B are arranged separately at both ends of the tertiary battery cell 31 . Films 331 and 332 made of a predetermined material are formed on the surfaces of the electrodes 32A and 32B. The films 331 and 332 are made of different materials.

The tertiary battery cell 31 generates an electromotive force due to a change in temperature even if the temperature of the electrode 32 is the same. The electromotive force of the tertiary battery cell 31 can be about 40 mV when the temperature changes by 30° C., for example, in a state where there is no temperature difference between the electrodes 32 .
The tertiary battery section 30 can have a plurality of tertiary battery cells 31 connected in series. Connection of the tertiary battery cells 31 can be performed by electric wires 75 . The series connection is such that, for example, electrode 32B with membrane 332 is connected to electrode 32A with membrane 331 of the next tertiary battery cell 31 . The number of cells to be connected in series is not particularly limited. For example, by connecting 20 to 30 tertiary battery cells 31 in series, an electromotive force of about 1 V can be obtained. The tertiary battery cells 31 may be connected in parallel, or may be connected in parallel and connected in series.

A wire 75 and a heat conducting member 70 are connected to the electrodes 32A and 32B positioned at both ends of the tertiary battery cell 31 .
In the heat conducting member 70 connected to the tertiary battery cell 31, the base end portion 71 is connected to the electrodes 32A and 32B. The tip portion 72 is arranged on the road surface layer 3 . If the distal end portion 72 of the heat conducting member 70 connecting the base end portion 71 to the electrode 32A and the distal end portion 72 of the heat conducting member 70 connecting the base end portion 71 to the electrode 32B are insulated, they have the same temperature. can be placed in position.
For example, the proximal end portion 71 may be connected to a covering that covers the entire housing 36 with a material having a high thermal conductivity.

Since the thermoelectric conversion cell 21 and the tertiary battery cell 31 can be composed of the housings 26, 36, the electrolyte solutions 25, 35, and the electrodes 22, 32, they can be manufactured at low cost compared to solar panels, for example. The simple structure reduces failures. Further, by increasing the strength of the housings 26 and 36, it is possible to meet the demand for load bearing performance.
For the thermoelectric conversion cell 21 and the tertiary battery cell 31, for example, concrete or plastic housings 26, 36 are installed at the construction site, and electrolyte solutions 25, 35 and electrodes 22, 32 are placed in the housings 26, 36 at the construction site. It can be constructed by a method of putting it in, and can be easily embedded in the pavement.

(storage unit)
The power storage unit 40 is a device having a storage battery that can be charged and discharged. The storage battery can be, for example, a lithium ion battery or the like. The electricity storage unit 40 can store electricity generated by the thermoelectric conversion cell unit 20, the tertiary battery unit 30, and the photoelectric conversion unit 60 described later. Charging and discharging of power storage unit 40 is controlled by control unit 50 .

(control part)
The control unit 50 is a device that receives electricity generated by the thermoelectric conversion cell unit 20 , the tertiary battery unit 30 , and a photoelectric conversion unit 60 described later, and controls charging and discharging of the power storage unit 40 . Further, the control unit 50 can adjust the power and output it to the outside of the device unit 10 . As an example is shown in FIG. 5, the control unit 50 is connected to the thermoelectric conversion cell unit 20, the tertiary battery unit 30, the photoelectric conversion unit 60, and the electricity storage unit 40, and has a power output terminal POUT.
The control unit 50 can select whether or not to receive the generated electricity for each of the thermoelectric conversion cell unit 20, the tertiary battery unit 30, and the photoelectric conversion unit 60, and can also adjust the amount of received electricity.
Control unit 50 also controls charging and discharging of power storage unit 40 . Excess power can be sent to power storage unit 40 and charged while being adjusted so as not to overcharge, and when output power is insufficient, power storage unit 40 can be discharged to compensate.

(Laminate part)
The laminated portion 80 is a member that supports the road surface layer 3 . The laminated portion 80 is formed by stacking unit structures 81 having voids. In the unit structure 81, each layer is rotated by 90 degrees and overlapped. In addition, the unit structure 81 suppresses slippage between the layers, for example, by arranging the protrusions on the upper surface so as to mesh with the recesses on the lower surface. The laminated portion 80 can be formed to match the thickness of the roadbed layer 2 by adjusting the number of layers of the unit structures 81 . The material of the unit structure 81 can be plastic, for example.
Since the unit structures 81 of the laminated portion 80 have voids, the permeated rainwater can be stored in the roadbed layer 2 . In addition, the laminated portion 80 has sufficient strength to withstand the traffic load of people and vehicles passing on the pavement structure 1, and a space for installing the device portion 10 in the roadbed layer 2 is secured. can be done.

(road surface layer)
The road surface layer 3 is a layer that becomes the road surface of the pavement structure 1 . The road surface layer 3 is formed by arranging temperature difference producing plates 65 which are plate-shaped members, and has a photoelectric conversion unit 60 that generates electricity by light inside the temperature difference producing plate 65 .

(Photoelectric converter)
The photoelectric conversion unit 60 is a device that has solar cells that are connected in series and in parallel and that can generate power using light. A solar cell can be, for example, monocrystalline or polycrystalline silicon. In single-crystal or polycrystalline silicon, light with a wavelength shorter than about 1.1 μm, which is an infrared region close to visible light, can be used for power generation.

(Temperature difference plate)
The temperature difference producing plate 65 is a plate-like member capable of producing a temperature difference in the depth direction. On the upper surface side of the temperature difference expression plate 65, the photoelectric conversion section 60 is arranged so as to extend in the planar direction of the plate.
For example, one of the tip portions 72 of the heat conduction member 70 from the two types of electrodes of the thermoelectric conversion cell 21 is arranged on the lower surface of the temperature difference expression plate 65, and the other is arranged near the center of the temperature difference expression plate 65 in the thickness direction. Thus, the temperature difference between the two types of electrodes of the thermoelectric conversion cell 21 can be increased.
The tip portion 72 of the heat conduction member 70 from the two types of electrodes of the thermoelectric conversion cell 21 of the tertiary battery cell 31 is arranged, for example, on the lower surface of the temperature difference expression plate 65, thereby shortening the length of the heat conduction member 70. Therefore, the temperature change of the electrodes of the tertiary battery cell 31 can be effectively increased. Also, by arranging it on the upper surface of the temperature difference manifesting plate 65, it is possible to utilize the temperature change in the vicinity of the road surface.
The upper surface side of the temperature difference expression plate 65 relative to the photoelectric conversion unit 60 is formed of a material that transmits light in a wavelength band that can be used by the photoelectric conversion unit 60 for power generation. It is preferable that the material of the temperature difference manifesting plate 65 is plate-shaped reinforced plastic. The thickness of the temperature difference producing plate 65 can be, for example, about 5 cm.
The upper surface of the temperature difference expression plate 65, which is the upper surface of the road surface layer 3, is processed to prevent slipping of pedestrians, vehicles, and the like. To prevent slipping, for example, aggregates are scattered on the upper surface to form unevenness, and the upper surface may be covered with a binder that holds the aggregates, or the upper surface may be coated with a resin having a large friction coefficient. good too.

In the pavement structure 1 according to the present invention, the device section 10 has at least one of a tertiary battery section 30 that generates power by a temperature change of electrodes and a thermoelectric conversion cell section 20 that generates power by a temperature difference between electrodes. The tertiary battery unit 30 can generate electricity by utilizing temperature changes that occur in the pavement structure 1 during the day when the temperature rises and at night when the temperature decreases, and the thermoelectric conversion cell unit 20 is, for example, Power can be generated by utilizing the temperature difference that occurs in the depth direction of the pavement structure 1 . Therefore, the pavement structure 1 can continuously extract electric power from the environment such as facility infrastructure. In addition, for example, even if the amount of sunlight and the hours of sunlight for photovoltaic power generation cannot be ensured, it is possible to effectively utilize temperature changes and temperature differences in environments such as facility infrastructure to generate power.
The pavement structure 1 is formed by stacking the unit structures 81 in the laminated part 80, so that the pavement structure 1 has sufficient strength against the traffic load, improves the efficiency of the paving work, and improves the workability. can. In the pavement structure 1, since the laminated portion 80 has voids, rainwater can be stored in the roadbed layer 2 to reduce puddles on the road surface. In addition, the box-shaped device section 10 can be installed with an electrical device for power generation or the like inside, and can protect the electrical device from rainwater, impact, or the like.

In the pavement structure 1, the base end portion 71 of the heat conducting member 70, which serves as a heat conduction path, is connected to an electrode provided in the tertiary battery portion 30, and the tip portion 72 is arranged on the road surface layer 3, thereby forming a tertiary battery. The change in temperature received by the electrodes of the section 30 can be increased, and the amount of power generation can be increased.
In the pavement structure 1, the base ends 71 of the heat conducting members 70, which serve as heat conduction paths, are connected to the two types of electrodes of the thermoelectric conversion cell unit 20, respectively, and the tip ends 72 corresponding to the respective base ends 71 are arranged at different depths in the road surface layer 3, the temperature difference received by the electrodes of the thermoelectric conversion cell unit 20 can be increased, and the amount of power generation can be increased.

The road surface layer 3 of the pavement structure 1 has the photoelectric conversion unit 60 that generates electricity by light, so that a wide area such as a road can be effectively utilized.
Since the road surface layer 3 is made of plate-shaped reinforced plastic, the pavement structure 1 can be manufactured, for example, in a factory or the like, and the photoelectric conversion unit 60 can be provided in the road surface layer 3 in advance. In addition, by arranging plate-shaped reinforced plastics, the road surface layer 3 can be formed, and the efficiency of work at the construction site can be improved while ensuring the strength of the road surface layer 3 .
In the pavement structure 1, since the device unit 10 has the power storage unit 40, the power storage unit 40 is charged during a time period when the power generation amount of the thermoelectric conversion cell unit 20, the tertiary battery unit 30, and the photoelectric conversion unit 60 is large, and the power generation amount Electric power can be supplied by discharging the power storage unit 40 during a period when the energy is small, and electric power can be supplied as stable natural energy for 24 hours.

The control unit 50 of the device unit 10 controls charging and discharging of the power storage unit 40 , so that the pavement structure 1 can suppress overcharging and stably supply electric power. In addition, since the control unit 50 adjusts and supplies power, it is possible to supply power in accordance with roadside equipment such as lighting, signals, and surveillance cameras, and equipment such as electronic equipment, heavy electric machinery, and temperature sensors. , the power harvested from the environment can be used for general purposes.
In the pavement structure 1, the upper surface of the road surface layer 3 is coated with aggregates and a binder that holds the aggregates, thereby suppressing the slipping of pedestrians and vehicles. Even if there is, pedestrian safety and smooth use can be achieved.

(Modification)
Next, a modification 21S of the thermoelectric conversion cell will be described. As an example is shown in FIG. 3B, the modification 21S is different from the thermoelectric conversion cell 21 in that protrusions 28A are formed on the outer surfaces of the electrodes 22A and the tips of the protrusions 28A protrude from the housing 26. Other configurations are common to the thermoelectric conversion cell 21 . A protrusion 28B is formed on the outer surface of the electrode 22B in the same manner as the protrusion 28A, and the tip of the protrusion 28B protrudes from the housing 26. As shown in FIG.
The material of the protrusions 28A and 28B may be metal, or resin or the like in which a substance having high thermal conductivity processed into powder or fiber is dispersed.
Modification 21S can improve thermal contact with the surroundings by means of protrusions 28A and 28B of electrodes 22A and 22B, increase the temperature difference between electrodes 22A and 22B, and increase the amount of power generation.

The device section 10 may have either one of the thermoelectric conversion cell section 20 and the tertiary battery section 30, or both. A plurality of device units 10 may be provided, and the combination of electrical devices may be different for each of the plurality of device units 10 . The thermoelectric conversion cell units 20 , the tertiary battery units 30 , and the power storage units 40 of the device unit 10 provided in plurality can be controlled by one control unit 50 or in cooperation with a plurality of control units 50 .
The control unit 50 may include, for example, a power input terminal that allows the power storage unit 40 to be charged from the outside.
The control unit 50 may have a signal input terminal for inputting a control signal, temperature information, etc. from the outside, for example. For example, a signal output terminal capable of monitoring the amount of power generated by the thermoelectric conversion cell unit 20, the tertiary battery unit 30, and the photoelectric conversion unit 60 may be provided. For example, the power generation amount may be simulated from the temperature information input from the temperature sensor provided in the pavement structure 1, and if the simulation result is significantly different from the received power generation amount, an alarm signal may be issued from the signal output terminal. good.

The thermoelectric conversion cells 21 and 21S may be installed such that the electrodes 22A and 22B are separated in the depth direction of the pavement structure 1 . Thereby, the temperature difference in the depth direction of the pavement structure 1 can be efficiently transmitted to the electrodes of the thermoelectric conversion cells 21 and 21S. Furthermore, it is also preferable to arrange materials with high thermal conductivity above and below the thermoelectric conversion cells 21 and 21S. Thereby, the temperature difference can be concentrated at the positions of the thermoelectric conversion cells 21 and 21S.
The thermoelectric conversion cell unit 20 may be installed by providing a region where the temperature difference manifesting plate 65 is not arranged on the road surface layer 3 . Since the thermoelectric conversion cells 21 and 21S are devices with low thermal conductivity, the temperature difference occurring at the position of the road surface layer 3 can be utilized. Further, the strength of the housing 26 can be increased as necessary, and even when installed on the road surface layer 3, sufficient durability against traffic loads and the like can be achieved.
The device section 10 may have various columnar or spherical shapes as long as it has a space inside for installing the electrical device.
The device section 10 can have a strength that can withstand the traffic load of people, vehicles, and the like that pass on the pavement structure 1 . The strength of the box-shaped device portion 10 may be increased to support the road surface layer 3 together with the laminated portion 80 . As a result, the pavement structure 1 can increase the degree of freedom in the installation location of the device unit 10. For example, even when there is no space in the roadbed layer 2, such as when a buried pipe is installed side by side in the roadbed layer 2, Even so, it is possible to easily secure a space for installing the device section 10 .

1 pavement structure 2 roadbed layer 3 road surface layer 4 base layer 10 device section 20 thermoelectric conversion cell section 21 thermoelectric conversion cell 22 electrode 231 membrane 232 membrane 25 electrolyte solution 26 housing 30 tertiary battery section 31 tertiary battery cell 32 electrode 35 electrolyte solution 40 power storage unit 50 control unit 60 photoelectric conversion unit 65 temperature difference expression plate 70 heat conduction member 71 base end (heat conduction member)
72 tip (heat conducting member)
80 laminated part 100 ground 200 ground

Claims (8)

A pavement structure in which a roadbed layer and a road surface layer supported by the roadbed layer are installed,
The roadbed layer is
a laminate portion formed by stacking unit structures having voids;
a box-shaped device section,
The apparatus section is a pavement structure having at least one of a tertiary battery section that generates power according to a temperature change of the electrodes and a thermoelectric conversion cell section that generates power according to a temperature difference between the electrodes. The device section has the tertiary battery section,
A plurality of heat-conducting members having one distal end and one proximal end and serving as heat conduction paths between the distal end and the proximal end,
connecting the base end portion of the thermally conductive member to the electrode provided in the tertiary battery portion;
2. The pavement structure according to claim 1, wherein the tip portion corresponding to the base end portion connected to the electrode of the tertiary battery portion is arranged on the road surface layer. The device section has the thermoelectric conversion cell section,
A plurality of heat-conducting members having one distal end and one proximal end and serving as heat conduction paths between the distal end and the proximal end,
connecting the base end portion of the thermally conductive member to the electrode provided in the thermoelectric conversion cell portion;
3. The tip portions corresponding to the respective base end portions connected to different electrodes of one of the thermoelectric conversion cell units are arranged at different depths in the road layer according to claim 1 or claim 2. paving structures. The pavement structure according to any one of claims 1 to 3, wherein the road surface layer has a photoelectric conversion unit that generates power by light. 5. The pavement structure according to claim 4, wherein the road surface layer is a plate-like reinforced plastic. The pavement structure according to any one of claims 1 to 5, wherein the device section has an electricity storage section that stores generated electricity. 7. The pavement structure according to claim 6, wherein the device section controls charging and discharging of the power storage section and has a control section that adjusts and supplies electric power. 8. The pavement structure according to any one of claims 1 to 7, wherein the upper surface of the road surface layer is coated with aggregate and a binder that holds the aggregate.

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