An open parking lot intelligent management system based on self-sensing asphalt concrete pavement

Abstract

The application discloses an open parking lot intelligent management system based on self-sensing asphalt concrete pavement, and belongs to the field of intelligent pavement material research and development and open parking lot management. The application adds stainless steel micro wires with excellent electric conductivity, micron-level diameter, high aspect ratio and high flexibility or uses the stainless steel micro wires and nano fillers in combination to endow the asphalt concrete with electric conductivity and sensing performance on the basis of guaranteeing excellent mechanical and deformation performance of the asphalt concrete. The self-sensing asphalt concrete full-size pavement upper layer, wearing layer, cover layer, strip-shaped upper layer and rapid repair layer are prepared by using conventional mixing and compaction processes, and then the dynamic monitoring of vehicle parameters is realized without external sensors, and the monitoring parameters, parking lock and mobile phone payment APP are combined into a software and hardware integrated control system through a controller, so that the intelligent monitoring and management of the open parking lot are realized.

Description

TECHNICAL FIELD

[0001] The present application relates to an open parking lot intelligent management system based on self-sensing asphalt concrete pavement, belonging to the field of intelligent pavement materials and the field of urban open parking lot management. BACKGROUND

[0002] With the development of economy and the improvement of people's living standards, the number of family cars in China is increasing. This brings a great burden to the operation and management of urban traffic, especially the parking problem of vehicles is becoming increasingly serious. The relevant management departments of each city are implementing various measures to solve the problem of urban parking difficulty, which includes gradually opening the parking lots of public utility management units and fully utilizing or transforming the narrow space of existing urban pavement to set up open parking lots. Existing practical experiments have proved that the setting of urban pavement open parking lots has significantly eased the problem of urban parking difficulty, but the management of open parking lots currently relies on on-site staff to complete, on the one hand, manual charging has the problems of long charging time and heavy workload, on the other hand, charging by the time leads to the occurrence of unfair events, thereby reducing the turnover rate of short-term parking spaces; it can also rely on external cameras, infrared, ground magnetic coils and ultrasonic sensors to realize the management of open parking lots, but the installation of these sensors is difficult, the installation cost is high, the data needs to be frequently updated, and the road structure is damaged; in addition, when the above sensors are used in open parking lots, they can usually only detect whether a vehicle is parked or not, and manual or camera cooperation is required to complete the management of open parking lots, which greatly increases the cost and easily causes poor management problems, high cost and maintenance cost, the need for additional support structure greatly limits the real-time and accuracy of traffic signal collection. Under the premise of not affecting the use function of the pavement, setting up special sensors for open parking spaces and establishing a related information collection system is expected to solve the management difficulty problem of open parking lots.

[0003] The addition of conductive fillers can endow traditional pavement structure material, asphalt concrete, with electrical conductivity and sensing performance on the basis of ensuring excellent mechanical and deformation performance, and thus realize dynamic monitoring of vehicle parameters without external sensors. The integration of the monitored parameters, parking lock and mobile phone payment APP into a software integrated control system is an effective measure to solve the problems encountered in existing open parking lots. In addition, the self-sensing asphalt concrete pavement can be completed using conventional mixing and compaction processes, and can be paved only at the site of the proposed open parking lot, or a thin layer of self-sensing asphalt concrete can be paved on the existing asphalt concrete pavement, or it can be used as a rapid repair asphalt surface treatment and asphalt fine sand overlay. However, in existing studies, it is found that carbon-based nanofillers are difficult to disperse uniformly in asphalt concrete, thereby failing to form an effective conductive and sensing network; existing carbon fiber conductive materials are prone to brittle fracture during the large deformation of asphalt concrete pavement, thereby failing to ensure long-term stable sensing performance; and existing steel fiber conductive fillers are easily pushed away by coarse aggregates in asphalt concrete due to their large diameter and stiffness, thereby resulting in poor improvement effect on the electrical conductivity and sensing performance of asphalt concrete at low dosage, and high-dosage steel fibers will affect the compactness and durability of asphalt concrete. SUMMARY

[0004] To solve the above problems, the purpose of the present application is to provide an open parking lot intelligent management system based on a self-sensing asphalt concrete pavement with excellent performance such as high sensitivity, stable sensing performance, easy installation, easy maintenance, good compatibility, and less influence from external conditions.

[0005] Technical solution:

[0006] A self-sensing asphalt concrete material, comprising asphalt concrete and conductive fillers.

[0007] The conductive fillers are stainless steel microfilaments or a mixture of stainless steel microfilaments and nanofillers.

[0008] A self-sensing asphalt concrete pavement panel made of the self-sensing asphalt concrete material.

[0009] The preparation method of the pavement panel: all raw materials (stainless steel microfilaments, asphalt, mineral powder, aggregate) are preheated at a temperature of 140-160°C for 1.5-2 hours, then the stainless steel microfilaments or the mixture of stainless steel microfilaments and nanofillers are mixed and stirred with asphalt and mineral powder at 140-160°C for 60-120 s, the aggregate is added and stirred at 140-160°C for 120-240 s, and the panel is formed at 130-150°C with 90-120 compaction times; during the panel forming process, stainless steel mesh positive and negative electrodes are embedded.

[0010] The application discloses an open parking lot intelligent management system based on self-sensing asphalt concrete pavement, and belongs to the field of intelligent parking lot management.

[0011] The application discloses an open parking lot intelligent management system based on self-sensing asphalt concrete pavement, and belongs to the field of intelligent parking lot management.

[0012] Further, in the above design scheme, the asphalt concrete matrix used can be fine-grained asphalt concrete for the upper layer, asphalt mastic mixture, anti-skid wearing layer asphalt concrete, ultra-thin wearing layer asphalt concrete or asphalt concrete for rapid repair or asphalt concrete for asphalt cover layer

[0013] Further, in the above design scheme, high-aspect-ratio, high-conductivity and high-erosion-resistance stainless steel micro wires or composite high-aspect-ratio, high-conductivity and high-erosion-resistance stainless steel micro wires and nano fillers are used as conductive fillers for preparing the self-sensing asphalt concrete pavement, the diameter of the stainless steel micro wires is 6-30 μm, the length is 6-15 mm, the volume content is 0.5-2.0 vol% of the asphalt concrete, and the nano fillers can be carbon nanotubes, nickel-plated carbon nanotubes, nano carbon black and graphene, etc.

[0014] The volume content of the nano fillers is 0.01-0.1 vol% of the asphalt volume.

[0015] Further, in the above design scheme, all raw materials are preheated at a temperature of 140-160 ℃, the preheating time is 1.5-2 hours, then the stainless steel micro wires or the mixture of the stainless steel micro wires and the nano fillers are mixed and stirred with the asphalt and the mineral powder at 140-160 ℃ for 60-120 s, the aggregate is added and stirred at 140-160 ℃ for 120-240 s, and the pavement is formed at 130-150 ℃, the compaction frequency is 90-120 times; the stainless steel mesh positive and negative electrodes are embedded in the pavement during pavement forming. If the composite stainless steel micro wires and the nano fillers are used as the conductive fillers, the nano fillers are first uniformly compounded with the stainless steel micro wires, and then the above stirring process is performed.

[0016] Further, in the above design scheme, the embedded stainless steel mesh positive and negative electrodes are placed at 1 / 5 and 3 / 5 of the thickness of the self-sensing concrete upper layer as signal collection electrodes of the self-sensing asphalt concrete pavement, the single-hole side length of the stainless steel mesh electrode is 2-5 mm, and according to the pavement panel monitoring area, several spaces with a side length of 40-100 mm are left at intervals of 20-50 mm.

[0017] Further, in the above design scheme, the weight, model, parking time and other data of the parked vehicle are obtained according to the change of the self-sensing asphalt concrete resistivity.

[0018] Further, in the above design scheme, the vehicle parameter data signal such as weight, model, parking time and the like obtained by monitoring the self-sensing asphalt concrete is combined with the parking lock and the mobile phone payment APP to form a software and hardware integrated control system.

[0019] The above open parking lot intelligent management system based on the self-sensing asphalt concrete pavement can be applied to the management of the city open parking lot in the form of self-sensing asphalt concrete full-size pavement upper layer, wearing layer, cover layer, or strip-shaped upper layer and rapid repair layer.

[0020] The self-sensing asphalt concrete of the application improves the electrical conductivity of the asphalt concrete and endows it with sensing performance by incorporating a special fine steel micro-wire with a stainless steel substrate, high electrical conductivity, micron-level diameter, high aspect ratio and high softness, or by using a stainless steel micro-wire in combination with a nano filler. The self-sensing asphalt concrete is mainly based on the following three aspects: 1) due to the micron-level diameter, a low amount of stainless steel micro-wire can be widely distributed in the asphalt concrete to form a conductive path, and when used in combination with a nano filler, the amount of stainless steel micro-wire can be further reduced; 2) due to the high aspect ratio, the stainless steel micro-wire has high flexibility and is easily overlapped under the pushing of the aggregate without causing tire puncture; 3) due to the stainless steel substrate, the incorporation of the stainless steel micro-wire can ensure the long-term stability of the mechanical, durability and electrical properties of the asphalt concrete. At the same time, the sensing signal of the self-sensing asphalt concrete is combined with the parking lock and the mobile phone payment APP to form a software integrated control system for monitoring and charging the vehicles entering and leaving the open parking lot. In addition, the open parking lot intelligent management system based on the self-sensing asphalt concrete pavement can be applied to the city open parking lot intelligent management in the form of self-sensing asphalt concrete full-size pavement upper layer, wearing layer, cover layer, or strip-shaped upper layer and rapid repair layer.

[0021] Inventive beneficial effects: The present application improves the electrical conductivity of asphalt concrete and endows it with sensing performance by incorporating stainless steel material as the matrix, high electrical conductivity, micron-level diameter, high aspect ratio and high softness of ultra-fine steel microfilaments or composite use of stainless steel microfilaments and nanofiller as conductive filler, which overcomes the problems of high dosage, high cost and poor dispersibility of commonly used carbon-based conductive fillers, solves the problems of easy corrosion of commonly used steel fiber conductive fillers, poor modification effect at low dosage, influence on compaction and durability of asphalt concrete at high dosage, and adverse effects on tires due to high stiffness. Based on the open parking lot intelligent management system of self-sensing asphalt concrete, the self-sensing asphalt concrete can be directly used in the form of upper layer of self-sensing asphalt concrete for urban open parking lot area, or the self-sensing asphalt concrete can be poured in the form of surface layer in the urban road area intended for open parking lot, or the self-sensing asphalt concrete can be poured in the form of strip or rapid repair, the vehicle parameters and the driving-in, driving-out and parking time of the vehicle are sensed through the change of the resistance signal of the self-sensing asphalt concrete, and a software integrated control system is formed by the parking lock and the mobile phone payment APP, which is expected to solve the problem of difficult manual management of urban open parking lot, and solve the problems of high cost and maintenance cost of commonly used traffic detection sensors (including infrared photoelectric sensor, inductive coil sensor, microwave radar sensor and video image detector), weather influence, and the need for additional support structure, improve the efficiency of open parking lot management, and provide a new idea for the application of intelligent road materials in urban management. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is the deformation and resistivity change rate and its sensitivity diagram of self-sensing asphalt concrete pavement under two wheel loads. DETAILED DESCRIPTION

[0023] The following non-limiting examples can enable those skilled in the art to more fully understand the present application, but in no way limit the present application.

[0024] In the sensing performance test of self-sensing asphalt concrete slab in the laboratory, strain gauges are attached to both ends of the self-sensing asphalt concrete slab specimen, the strain of the specimen under applied wheel load and other external loads is measured, the resistance change of the self-sensing asphalt concrete slab specimen under load is measured by a direct current resistance meter, the sensitivity of the self-sensing asphalt concrete is determined by the resistance change rate corresponding to the unit strain change, and data support is provided for inferring the vehicle weight parameter according to the size of the resistivity change rate in actual application. The resistance signal is connected to the control gate of the ground lock, so that the ground lock is lowered when the resistance is reduced, and the ground lock is raised when the resistance is increased, the parking time is determined according to the interval time of the resistance change, and the vehicle weight, vehicle type and other parameters of the parking are determined according to the resistance change rate or the resistivity change rate.

[0025] Example 1

[0026] The embodiment is based on the self-sensing asphalt concrete pavement panel with high sensitivity, excellent mechanical properties, good long-term stability, easy to arrange, easy to maintain and the like to develop an open parking lot intelligent management system.

[0027] In the embodiment, fine-grained asphalt concrete (AC-13) is used as the base of the upper surface layer of the pavement; the diameter of the stainless steel micro-wire used is 20 μm, the length is 10 mm, the dosage is 1.0 vol% of the volume of the asphalt, and no nano filler is used; the stirring process is that the preheating temperature of all raw materials is 160 ℃, the preheating time is 1.8 hours, the stainless steel micro-wire is first mixed with the asphalt and the mineral powder at a high temperature of 150 ℃ for 90 s, then the aggregate is added and stirred at a high temperature of 150 ℃ for 180 s, the molding temperature is 140 ℃, and the compaction frequency is 100 times; the size of the reduced-scale newly-poured pavement panel is 300 mm×300 mm×50 mm, the stainless steel mesh electrode with a total area of 300 mm×300 mm is buried at 1 / 5 and 3 / 5 of the thickness of the panel, the square single-hole of the electrode mesh has a side length of 3 mm, and there are nine 60 mm×60 mm holes arranged in three rows and three columns according to an interval of 40 mm; after the self-sensing asphalt concrete panel is formed, a standard wheel load (0.7 MPa) is applied, the monitoring sensitivity data is obtained according to the change of the resistivity of the self-sensing asphalt concrete, and it is measured that the strain of the pavement under the wheel load in the embodiment is 302 με, the corresponding resistivity change rate is 76.7%, and the sensitivity obtained therefrom is 76.7% / 302×10 6 =2539, which is obviously higher than the sensitivity 2 of the commercially available strain gauge, as shown in Figure 1 .

[0028] The stainless steel mesh electrode, the parking lock, the mobile phone and the controller are connected to form a software integrated control system, and the vehicle parameters and the driving-in, driving-out and parking time of the vehicle can be viewed in real time through the APP of the mobile phone.

[0029] Embodiment 2

[0030] The fine-grained asphalt concrete (AC-13) is used as the base body of the pavement surface layer; the diameter of the stainless steel micro-wire used is 30 μm, the length is 15 mm, and the mixing amount is 0.5 vol% of the volume mixing amount of the asphalt; the length of the carbon nanotube used is 2 μm, the outer diameter is 10 nm, and the mixing amount is 0.05 vol% of the volume mixing amount of the asphalt; the stirring process is that the preheating temperature of all raw materials is 150 ℃, the preheating time is 1.5 hours, the stainless steel micro-wire and the carbon nanotube are mixed first, the mixed material is mixed with the asphalt and the mineral powder at a high temperature of 140 ℃ for 120 s, the aggregate is added at a high temperature of 150 ℃ for 240 s, the molding temperature is 150 ℃, and the compaction times are 90 times; the size of the molded reduced-scale newly-poured pavement slab is 300 mm×300 mm×50 mm, the total area of the stainless steel mesh electrode is 300 mm×300 mm, the square single-hole side length of the electrode mesh is 3 mm, and there are nine 40 mm×40 mm holes arranged in three rows and three columns according to an interval of 30 mm; and the slab is molded.

[0031] Example 3

[0032] The fine-grained asphalt concrete (AC-13) is used as the base body of the pavement surface layer; the diameter of the stainless steel micro-wire used is 6 μm, the length is 10 mm, and the mixing amount is 2.0 vol% of the volume mixing amount of the asphalt; the stirring process is that the preheating temperature of all raw materials is 140 ℃, the preheating time is 2.0 hours, the stainless steel micro-wire is mixed with the asphalt and the mineral powder at a high temperature of 160 ℃ for 60 s, the aggregate is added at a high temperature of 150 ℃ for 200 s, the molding temperature is 140 ℃, and the compaction times are 120 times; the size of the molded reduced-scale newly-poured pavement slab is 300 mm×300 mm×50 mm, the total area of the stainless steel mesh electrode is 300 mm×300 mm, the square single-hole side length of the electrode mesh is 3 mm, and there are nine 80 mm×80 mm holes arranged in three rows and three columns according to an interval of 20 mm; and the slab is molded.

[0033] Example 4

[0034] The fine-grained asphalt concrete (AC-13) is used as the base of the upper layer of the road surface; the diameter of the stainless steel micro-wire is 15 μm, the length is 6 mm, the mixing amount is 2.0 vol% of the volume mixing amount of the asphalt, the preheating temperature of all raw materials is 155 ℃, the preheating time is 1.5 hours, the stainless steel micro-wire is mixed with the asphalt and the mineral powder at a high temperature of 155 ℃ for 100 s, then the aggregate is added at a high temperature of 160 ℃ for 120 s, the molding temperature is 130 ℃, and the compaction frequency is 100 times; the size of the reduced-scale newly-poured road surface panel is 300 mm×300 mm×50 mm, the total area of the stainless steel mesh electrode buried at 1 / 5 and 3 / 5 of the thickness of the panel is 300 mm×300 mm, the square single-hole side length of the electrode mesh is 3 mm, and there are nine 60 mm×60 mm holes arranged in three rows and three columns according to an interval of 40 mm.

[0035] Comparative Example 1

[0036] The "parking lock + handset mode" has the following specific operation: the parking lock of an empty parking space is in an upright state, when a vehicle approaches an empty parking space to prepare to park, the on-site manager remotely controls the parking lock to open to a flat state through the handset, the handset automatically generates the parking start time and the like, and the vehicle enters the empty parking space; after stable parking, the manager hands over the parking card to the vehicle owner, and at the same time remotely controls the parking lock to close to the upright state through the handset, and the vehicle owner leaves. When the vehicle exits, the vehicle owner first hands over the parking card to the on-site manager, the manager presents the parking time and the charging amount and the like by swiping the card through the handset, prints a ticket and hands it over to the vehicle owner, the vehicle owner pays the manager, the manager remotely controls the lifting road post to the ground through the handset, the vehicle exits, and the manager remotely controls the lifting road post to the rising state through the handset.

[0037] Comparative Example 2

[0038] The parking management equipment based on the linkage of geomagnetic and camera array mainly includes a geomagnetic sensor and a camera array, and the main principle is that the geomagnetic sensor is buried below the parking space and provides a trigger signal to a control unit, when a vehicle enters or exits the parking lot, the geomagnetic sensor senses that the own magnetic field is disturbed, and transmits the parking space change trigger signal to the control unit; after receiving the shooting command of the control unit, the camera array shoots the vehicle in the parking space, stores the image data in an image storage unit, and collects parking information.

[0039] Performance test

[0040] Table 1: Cost estimation of one use cycle of the product of the example and the comparative example

[0041] Example Stainless steel micro-fiber content Nano-filler content Sensitivity under rutting load Material cost (yuan / set) Installation cost (yuan / set) Maintenance cost (yuan / set) Replacement cost in life cycle (yuan / set) Labor management cost (yuan / set) Total (yuan / set) Example 1 1.0 vol% 0 2539 1600 200 0 0 0 1800 Comparative Example 1 - - - 200 200 200 600 1000 2200 Comparative Example 2 - - - 1200 500 200 500 0 2400

[0042] Note: The cost of each set of materials in the table refers to the pouring area of 1 m 3 of self-aware asphalt concrete slab and supporting signal acquisition, transmission and control system; the sensitivity of commercially available strain gauge is 2.

Claims

1. A self-sensing asphalt concrete pavement slab, characterized in that, The self-sensing asphalt concrete pavement is applied in the parking lot intelligent management system, and the vehicle weight, vehicle type, and parking time data of the parked vehicles are obtained based on the change in the resistivity of the self-sensing asphalt concrete pavement. The self-sensing asphalt concrete pavement is made of self-sensing asphalt concrete material; the self-sensing asphalt concrete material includes asphalt concrete and conductive filler. The conductive filler is stainless steel microwire or a mixture of stainless steel microwire and nanofiller; The stainless steel microwires have a diameter of 6-30 μm, a length of 6-15 mm, and a volumetric content of 0.5-2.0 vol of asphalt.

2. The self-sensing asphalt concrete pavement slab according to claim 1, characterized in that, The nanofiller is selected from at least one of carbon nanotubes, nickel-plated carbon nanotubes, nano carbon black, and graphene; The volumetric content of the nanofiller is 0.01-0.1 vol of the asphalt volume.

3. The self-sensing asphalt concrete pavement slab according to claim 2, characterized in that, The asphalt concrete may be fine-grained asphalt concrete, asphalt mastic aggregate mixture, anti-skid wear layer asphalt concrete, ultra-thin wear layer asphalt concrete, asphalt concrete for rapid repair, or asphalt concrete for asphalt overlay.

4. The self-sensing asphalt concrete pavement slab according to claim 1, characterized in that, The method for preparing the road panel is as follows: all raw materials are preheated at 140-160 ℃ for 1.5-2 hours. Then, stainless steel microwires or a mixture of stainless steel microwires and nanofillers are mixed with asphalt and mineral powder at 140-160 ℃ for 60-120 s. Aggregates are added and stirred at 140-160 ℃ for 120-240 s. The mixture is then molded at 130-150 ℃ and compacted 90-120 times. Stainless steel mesh electrodes are embedded during the road panel forming process.

5. A self-sensing asphalt concrete pavement slab according to claim 4, characterized in that, Stainless steel mesh electrodes are installed at 1 / 5 and 3 / 5 of the thickness of the road surface slab. The stainless steel mesh electrode has a single hole side length of 2-5 mm, and n spaces with a side length of 40-100 mm are left at intervals of 20-40 mm according to the monitoring area of ​​the road panel. Where n is an integer greater than 1.

6. An intelligent management system for an open parking lot based on self-sensing asphalt concrete pavement, characterized in that, The system includes a parking lock, a mobile phone, a controller, and a self-sensing asphalt concrete pavement panel as described in any one of claims 1-5. The controller integrates a power supply module, a drive module, a wireless communication network module, an ultrasonic ranging module, and a resistance testing module. The controller is connected to the microprocessor control potential in the parking lock via a wireless communication module. A wireless radio frequency identification receiver is embedded in the parking lock. The controller is electrically connected to a stainless steel mesh electrode and wirelessly connected to a mobile phone.

7. The management system according to claim 6, characterized in that, The self-sensing asphalt concrete pavement can be a full-size surface layer, a wear layer, a topcoat, or a strip-shaped surface layer and a quick-repair layer.

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