Road concrete pavement layer self-adaptive crushing method based on microwave-assisted resonance

Abstract

The invention belongs to the technical field of road maintenance, and discloses a road concrete pavement layer self-adaptive crushing method based on microwave-assisted resonance, and the specific technical scheme is as follows: a microwave heating device is used for pretreating a cut and divided crushing area, and a concrete layer is weakened through a heating effect of microwave radiation to realize separation of a pavement layer; when it is judged that the temperature of the concrete in the heating area reaches the needed temperature through the thermal infrared imager, the inherent frequency of the concrete is calculated, a calculation result is fed back to the resonance crushing device, and the resonance crushing device enables the pavement layer to generate forced vibration to be crushed by generating excitation frequency; the novel method for crushing the concrete pavement layer based on microwave-resonance energy coupling has the characteristics of being accurate, controllable, efficient, applicable to multiple scenes and the like, and can be matched with an acoustic emission system to realize closed-loop control of concrete crushing, so that the working environment of the concrete pavement layer is greatly improved, and the service life of the concrete pavement layer is prolonged. And the maintenance frequency of the equipment is greatly reduced while the crushing efficiency is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of highway maintenance, and particularly relates to a cement concrete pavement layer efficient breaking method combining microwave pre-splitting and resonance breaking collaborative operation. BACKGROUND

[0002] Cement concrete pavement is widely used due to its high strength, long service life and less maintenance. Most airports in the world are cement concrete runways. After being used for a period of time, the pavement layer of cement concrete pavement (airport runway, etc.) will have diseases such as cracking, broken slab, slab dislocation and subsidence. When the diseases are serious, the cement concrete pavement needs to be reconstructed.

[0003] Traditional reconstruction often adopts hydraulic breaking, pick breaking or sawing, which has low efficiency and high labor intensity. The particle size of broken concrete cannot meet the on-site recycling requirement, resulting in resource waste and great influence on traffic. The resonance breaking technology uses resonance principle (by adjusting the vibration frequency of the hammer head to approach the natural frequency of the cement concrete panel) to excite resonance, so that the cement concrete panel can be broken more easily. This method has the advantages of uniform gravel particle size, no damage to the roadbed, effective reduction of reflection cracks, low cost and less influence on road traffic, and is the development trend of future cement pavement reconstruction.

[0004] The existing resonance breaker has a significantly reduced breaking effect and reduced efficiency or even cannot effectively break the pavement with extremely high strength (such as C60 or above), high reinforcement ratio, ductile material (such as asphalt concrete) and a large number of soft foundation or cavities. The resonance breaker cannot be used in the area with a too thin or too thick concrete slab, complex underground pipelines or structures (such as bridge and culvert connection), and cannot form effective resonance due to the too thin concrete slab and cannot penetrate the energy due to the too thick concrete slab. In addition, the key components such as the exciter bearing and high-strength alloy breaking head are worn out quickly due to long-time work under high frequency and high load, and the replacement frequency is high, which has a high maintenance cost. The high-frequency vibration energy of the resonance device during construction can be transmitted to the surrounding through the soil and structure, and the influence range is wider than that of the traditional device with the same breaking effect. The resonance device may cause potential harm or interference to the adjacent sensitive buildings, underground pipelines (especially old pipelines), precision instruments or structures to be protected (such as ancient buildings and bridges), which seriously affects the construction efficiency and the applicability of the resonance device. SUMMARY

[0005] To solve the technical problems existing in the prior art, the present application provides a new method for breaking a concrete pavement layer based on microwave-resonance energy coupling, which has the characteristics of precise control, high efficiency, multi-scene application, etc., can be matched with an acoustic emission system to realize closed-loop control of concrete breaking, greatly improves the working environment of the concrete pavement layer, and greatly reduces the maintenance frequency of the equipment while improving the breaking efficiency.

[0006] To achieve the above-mentioned object, the technical scheme adopted by the present application is: a road concrete pavement layer self-adaptive breaking method based on microwave-assisted resonance, a concrete breaking device comprising a microwave heating device, a resonance breaking device and a data acquisition device, the microwave heating device being composed of a microwave heating wall composed of a plurality of magnetrons and horn waveguide arrays and an angle adjusting mechanism, a directional microwave heating device being used to perform non-contact irradiation on the surface layer of the concrete, and a micro-crack network being generated in the internal part of the concrete pavement layer through selective heating; due to the difference in thermal expansion coefficients of the steel bars and the concrete, an interface peeling phenomenon occurs between the steel bar layer and the concrete layer after heating. The resonance breaking device is composed of a vibration exciter and a breaking hammer head, the resonance frequency is adjusted to the modal frequency of the concrete after weakening by the microwave, so that the vibration intensity is greatly reduced, the interface between the steel bars and the concrete is blocked, and the energy conduction is greatly reduced.

[0007] The data acquisition device is composed of a GNSS positioning instrument, an acoustic emission sensor and an infrared thermal imager, the GNSS is short for Global Navigation Satellite System, satellite signal transmission is used to transmit real-time position and time information, and the position information of the resonance vehicle in the real-time driving process is calculated, so that the breaking device and the breaking area are conveniently matched in synchronization; the acoustic emission sensor mainly detects the structural damage of the concrete, when the internal cracks of the concrete are formed and expanded, stress relaxation occurs, part of the stored energy is released in the form of stress waves, and acoustic emission is generated. By measuring and analyzing the acoustic emission signals emitted by the concrete during the stress process, the damage of the internal structure of the concrete can be inferred, so that the size of the damage can be identified, the breaking state of the concrete pavement layer can be fed back, the control parameters of the two devices can be conveniently dynamically adjusted by the system, and the whole process of the concrete damage can be monitored; the infrared thermal imager is based on the relationship between the thermal radiation characteristics of an object and the temperature, captures the infrared radiation of the surface of the concrete and converts it into a visual temperature image, monitors the surface temperature of the concrete after microwave heating and transmits the temperature signal to the system controller, converts and calculates the natural frequency of the concrete, and obtains the natural frequency of the vibration-attenuated concrete after heating.

[0008] The specific steps of the breaking method are: first, using a microwave heating device to pretreat the broken area divided by cutting, weakening the concrete layer through the heating effect of microwave radiation, significantly reducing its mechanical properties such as uniaxial compressive strength, tensile strength and point load strength. After microwave irradiation, a certain temperature gradient will be formed inside the concrete pavement layer, resulting in different volume strains and stress states of each part inside, achieving the "layering" of the pavement layer and different structural parts (soil foundation, top surface of main beam). In addition, the infrared thermal imager is used to judge whether the temperature of the heated area of the concrete reaches the required temperature, and then the natural frequency of the concrete is calculated and fed back to the resonance breaking device. The resonance breaking device generates an excitation frequency to cause forced vibration of the cement concrete surface layer, while the lower layer structure still maintains its inherent properties due to the consumption of microwave heat, and the excitation of the upper layer does not cause cracks in the lower layer.

[0009] The microwave unit and the resonance unit are integrated on the same mobile platform, with a distance of 1-3m, and the control of both is performed by the system controller. The sensors of the data acquisition layer collect and calculate relevant data and feed them back to the system controller for integrated processing and data output control of different unit instructions.

[0010] The detailed steps of the breaking method are:

[0011] Step one, use a milling machine to divide the pavement layer into 2m x 2m standard breaking units, and use the contour scanner carried by the mobile platform to travel along the road surface and construct a 3D point cloud model. Project a visible light grid on the boundary of each breaking unit as a positioning reference to identify each breaking area.

[0012] Step two, the mobile platform drives to the center of the target breaking unit, adjusts the microwave heating device to descend to a distance of 20cm from the pavement layer, and the two-angle cone horn waveguide in the microwave heating device is arranged in an antenna array. Through the phase control of the horn waveguide array, the energy is focused, and the heating area is strictly limited within the target breaking unit. Adjust the horn waveguide array to 0° and irradiate the concrete surface vertically.

[0013] Step three, select the power parameter of the microwave heating device according to the strength grade of the pre-broken concrete pavement layer; use 5-10kW / m 2 for C30-C40, and use 15-20kW / m 2 for C50 and above.

[0014] Step four, infrared thermal imager real-time scanning pavement layer concrete surface temperature field, PID controller adjusts the output of magnetron and controls the pavement surface layer to heat to 100-150 DEG C, when the temperature > 150 DEG C, reduce the microwave heating power, when the temperature < 100 DEG C, improve the microwave heating power, according to the real-time feedback of infrared temperature measurement, dynamically adjust the microwave power of microwave heating device, control the temperature gradient parameter to keep ± 10 DEG C / m 2 ; prevent the high burst phenomenon of surface layer concrete caused by continuous high temperature in the internal concrete pavement layer.

[0015] Step five, acoustic emission sensor identifies the crack development of pavement layer surface, heating time lasts for 30-90s, sets crack width and density conditions, and automatically terminates heating and retracts microwave heating device to the initial position after reaching the standard.

[0016] Step six, the inherent frequency of pavement layer concrete is calculated and the excitation frequency is output.

[0017] Step seven, the frequency range of data acquisition device is restricted to 15-25Hz in the system controller, the acoustic emission sensor is used to monitor the broken energy efficiency in real time, and the microwave-resonance parameter combination is dynamically adjusted.

[0018] Step eight, the excitation frequency of the resonance breaking device is set, the system controller controls the inherent frequency of concrete , drives the variable frequency operation of the excitation system to , so that the excitation frequency is close to the inherent frequency of the concrete pavement layer to realize local breaking; the hydraulic servo system controls the amplitude of the resonance hammer head according to the strength grading of concrete, when the vibration intensity > 40Mpa, the amplitude is adjusted to 7-8mm, when the intensity < 30Mpa, the amplitude is adjusted to 5-6mm; the constant-speed breaking is carried out in the breaking unit, the vehicle driving speed is set to be inversely proportional to the amplitude, and the total range is set to be 1-3m / min; the acoustic emission sensor is used to monitor the characteristic frequency signal in real time, to judge the breaking state and control the depth error; the acoustic emission pulse signal generated when the concrete pavement layer is broken and the microcrack expands is different from the characteristic signal fluctuation frequency when the broken energy penetrates the weakened layer and reaches the lower layer structure (steel or complete concrete), the excitation device is interrupted when reaching the lower layer structure, and the breaking hammer head is lifted off the road.

[0019] Step nine, after the first block of pre-breaking area is broken, the microwave heating device is pre-displaced after scanning and positioning the second block of breaking unit; the second unit microwave heating device is started in advance 15s before the first unit breaking is completed; after the heating process of the second unit is completed, the vehicle moves to the second unit at the speed of 2m / min.

[0020] Compared with the prior art, the present application has the following specific beneficial effects:

[0021] I. The present application utilizes the selective heating characteristics of microwaves, resulting in high-frequency oscillation of polar molecules in the concrete pavement material under the action of the microwave electromagnetic field, frictional heat generation, and "thermal-mechanical-chemical" multiple destruction effects inside the structure, resulting in a network of micro-cracks that greatly reduces its uniaxial compressive strength, greatly reducing the energy consumption of resonance breaking.

[0022] II. Microwave energy decays exponentially within the concrete pavement, forming a clear gradient temperature field, achieving precise surface depth weakening of the broken area, and forming micro-gaps between the steel-reinforced concrete interface, blocking the continuous downward transmission of vibration energy. By adjusting the resonance breaking energy, precise target positioning is achieved, and the layered precise breaking protects other structural layers, providing a solution for the maintenance and modification of concrete pavement structures in high-speed road sections, bridges, tunnels, airport runways, and industrial parks.

[0023] III. The reduction of resonance frequency and vibration amplitude can effectively prolong the service life of the exciter bearing and the breaking hammer head, extend the maintenance cycle of the equipment, and greatly reduce the vibration and noise pollution.

[0024] IV. By combining the application of acoustic emission sensors, the present application can capture crack propagation signals in real time and dynamically adjust microwave power and resonance frequency, thereby better adapting to the breaking efficiency of concrete pavement layers under different working conditions and achieving intelligent closed-loop control of the entire breaking process. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The control logic diagram of the present application.

[0026] Figure 2 The monitoring logic diagram of the acoustic emission sensor.

[0027] Figure 3 The schematic diagram of the microwave heating device.

[0028] Figure 4 The schematic diagram of the microwave heating device connection mechanism.

[0029] Figure 5 The schematic diagram of the resonance breaking device.

[0030] Figure 6 The schematic diagram of the microwave-assisted resonance road concrete pavement self-adaptive breaking device.

[0031] Figure 7 The working condition of the road concrete pavement self-adaptive breaking method Figure 1 (microwave heating stage).

[0032] Figure 8 The working condition of the road concrete pavement self-adaptive breaking methodFigure 2 (Resonance breaking stage).

[0033] In the figure, 1 is a microwave heating wall, 2 is a speaker waveguide array, 3 is a microwave leakage prevention device, 4 is a lifting cylinder, 5 is an upper fixed frame, 6 is a telescopic frame, 7 is a flip articulated frame, 8 is a counterweight box, 9 is a lifting cylinder, 10 is a transverse cylinder, 11 is a vibration reduction frame, 12 is a crushing hammer head, 13 is an excitation box, 14 is a shear rubber shock absorber, 15 is an acoustic emission sensor, 16 is a vibration device, 17 is an infrared thermal imager, 18 is a microwave heating device, 19 is a radiator, 20 is an engine, and 21 is a cab. DETAILED DESCRIPTION

[0034] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0035] like Figures 1-2 As shown, the adaptive crushing method of road concrete pavement based on microwave-assisted resonance includes a cab 21 installed on a frame, an engine 20, a radiator 19 and a microwave heating device 18 are arranged at the front end of the frame, and an infrared thermal imager 17, a vibration device 16 and an acoustic emission sensor 15 are arranged below the cab 21.

[0036] A vibration frame is provided in the vibration device 16, and a counterweight box 8 and a lifting cylinder 9 are installed at the upper end of the vibration frame. The cylinder rod of the lifting cylinder 9 is connected to the vibration damping frame 11. A transverse cylinder 10 is provided in the vibration damping frame 11, and the cylinder rod of the transverse cylinder 10 is connected to the excitation box 13. A crushing hammer head 12 is installed at the bottom of the excitation box 13, and a shear-type rubber shock absorber 14 is installed between the excitation box 13 and the vibration damping frame 11.

[0037] The crushing device for concrete includes a microwave heating device 18, a resonance crushing device and a data acquisition device, such as Figures 3-4 As shown, the microwave heating device 18 is composed of a microwave heating wall 1 composed of multiple magnetrons and a horn waveguide array 2, and an angle adjustment mechanism. A microwave leakage prevention device 3 is provided inside the microwave heating wall 1. The microwave leakage prevention device 3 is connected to the telescopic frame 6 through a lifting cylinder 4. The telescopic frame 6 is installed at the front end of the vehicle frame through an upper end fixing frame 5. The microwave leakage prevention device 3 is hinged to the bottom end of the telescopic frame 6 through a flip hinge frame 7. The directional microwave heating device 18 is used to perform non-contact irradiation on the concrete surface. Through selective heating, a micro-crack network is generated inside the concrete pavement layer. Due to the different thermal expansion coefficients of steel bars and concrete, the interface peeling phenomenon occurs between the steel bar layer and the concrete layer after heating. Figure 5As shown, the resonance breaking device is composed of a vibration exciter and a breaking hammer head 12, and the resonance frequency is adjusted to the modal frequency of the weakened concrete after microwave weakening, so as to realize a significant reduction in vibration intensity and the interface between the steel bar and the concrete to achieve interface blocking of energy conduction, thereby greatly reducing resonance energy consumption and vibration propagation.

[0038] The data acquisition device is composed of a GNSS positioning instrument, an acoustic emission sensor 15 and an infrared thermal imager. GNSS stands for Global Navigation Satellite System, which uses satellite signals to transmit real-time position and time information, and thereby calculates the position information of the resonance vehicle in the real-time driving process, facilitating the synchronous matching of the breaking device and the breaking area. The acoustic emission sensor 15 mainly detects the structural damage of the concrete. When the internal cracks of the concrete form and expand, stress relaxation occurs, and part of the stored energy is released in the form of stress waves, producing acoustic emission. By measuring and analyzing the acoustic emission signals emitted by the concrete during the stress process, the internal structure of the concrete can be inferred, and the size of the damage can be identified, so as to feedback the breaking state of the concrete pavement layer and facilitate the dynamic adjustment of the control parameters of the two devices by the system, and monitor the whole process of concrete damage. The infrared thermal imager is based on the relationship between the thermal radiation characteristics of an object and temperature. By capturing the infrared radiation of the concrete surface and converting it into a visual temperature image, the surface temperature of the concrete after microwave heating is monitored, and the temperature signal is transmitted to the system controller. The natural frequency of the concrete is calculated and converted, and the natural frequency of the heated and vibration-attenuated concrete is obtained.

[0039] The method is realized by the following steps: as shown in Figures 6-8 As shown, first, the microwave heating device 18 is used to pretreat the breaking area divided by cutting, and the heating effect of microwave radiation is used to weaken the concrete layer, significantly reducing its mechanical properties such as uniaxial compressive strength, tensile strength and point load strength. After microwave irradiation, a certain temperature gradient is formed in the internal concrete pavement layer, different volume strains are generated, the stress state of each part inside is different, and the pavement layer and different structural parts (soil foundation and top surface of main beam) are "layered". In addition, the infrared thermal imager is used to judge whether the temperature of the concrete in the heated area reaches the required temperature, and the natural frequency of the concrete is calculated and fed back to the resonance breaking device. The resonance breaking device generates a vibration excitation frequency to cause forced vibration of the cement concrete surface layer, and the lower layer structure still maintains its inherent properties due to the consumption effect of microwave heat, so that the vibration of the upper layer does not cause cracks in the lower layer.

[0040] The microwave unit and the resonance unit are integrated on the same mobile platform, and the distance is controlled within 1-3m. The control of both is performed by the system controller. After the sensors of the data acquisition layer collect and calculate the relevant data, they are fed back to the system controller for integrated processing, and the data output of different unit instructions is controlled.

[0041] The detailed steps of the breaking method are:

[0042] Step one, divide the pavement pavement layer into 2m x 2m standard breaking units with a milling machine, and a profile scanner carried by a mobile platform travels along the pavement and constructs a 3D point cloud model, projects a visible light grid on the boundary of each breaking unit as a positioning reference, and identifies each breaking area;

[0043] Step two, the mobile platform drives to the center of the target breaking unit, adjusts the microwave heating device 18 to descend to 20 cm away from the pavement layer 20, the two-angle horn waveguide arranged in the microwave heating device 18 adopts an antenna array arrangement, and the energy focusing is realized through the phase control of the horn waveguide array 2, which strictly limits the heating area within the target breaking unit, adjusts the horn waveguide array 2 to 0° and vertically irradiates the concrete surface;

[0044] Step three, select the power parameters of the microwave heating device 18 according to the strength grade of the pre-broken concrete pavement layer; 5-10kW / m 2 for C30-C40, and 15-20kW / m 2 for C50 and above;

[0045] Step four, the infrared thermal imager scans the pavement layer concrete surface temperature field in real time, the PID controller adjusts the magnetron output and controls the pavement layer surface layer to heat to 100-150℃, when the temperature > 150℃, reduce the microwave heating power, when the temperature < 100℃, increase the microwave heating power, dynamically adjust the microwave power of the microwave heating device 18 according to the real-time feedback of the infrared temperature measurement, control the temperature gradient parameter to keep ±10℃ / m 2 ; prevent the surface concrete from exploding due to continuous high temperature in the internal concrete pavement layer;

[0046] Step five, the acoustic emission sensor 15 identifies the development of the pavement layer surface crack, the heating time lasts for 30-90s, sets the crack width and density conditions, and automatically terminates the heating and shrinks the microwave heating device 18 to the initial position after reaching the standard;

[0047] Step six, calculate the inherent frequency of the pavement layer concrete and output the excitation frequency, the calculation process of the system controller is:

[0048] Step S61: establish a temperature field model, and the controller obtains the internal temperature of the concrete pavement layer through the heat conduction equation:

[0049] ;

[0050] ;

[0051] In the formula, is the depth from the surface, for the microwave penetration depth, for the microwave frequency, for the dielectric loss factor of the concrete;

[0052] Step S62: Calculate the equivalent elastic modulus of the weakened concrete, based on the empirical formula for elastic modulus decay:

[0053] ;

[0054] wherein, is the maximum temperature in the heated concrete pavement, is the initial elastic modulus of the concrete, is the elastic modulus of the decayed concrete;

[0055] Step S63: Solve the natural frequency, simplify the cut concrete panel into a four-side free thin plate model, and the calculation formula of the natural frequency is:

[0056] ;

[0057] wherein, is the bending stiffness, is the mass per unit area, , is the size of the broken unit panel.

[0058] Step seven, constrain the frequency range of the data acquisition device in the system controller to 15-25 Hz, use the acoustic emission sensor 15 to monitor the breaking energy efficiency in real time, and dynamically adjust the microwave-resonance parameter combination;

[0059] Step eight, set the excitation frequency of the resonance breaking device, and the system controller controls the natural frequency of the concrete , drives the variable frequency operation of the excitation system to , so that the excitation frequency is close to the natural frequency of the concrete pavement to achieve local breaking; the hydraulic servo system controls the amplitude of the resonance hammer head according to the concrete strength grading, when the vibration intensity is >40Mpa, the amplitude is adjusted to 7-8mm, when the intensity is <30Mpa, the amplitude is adjusted to 5-6mm; in the breaking unit, the constant-speed breaking is set, the vehicle driving speed is inversely proportional to the amplitude adjustment, and the total range is set to 1-3m / min; as shown in Figure 2 , the characteristic frequency signal is monitored in real time by the acoustic emission sensor 15, the breaking state is judged, and the depth error is controlled; the acoustic emission pulse signal generated when the concrete pavement is in the internal aggregate fracture and micro-crack expansion is different from the characteristic signal fluctuation frequency when the breaking energy penetrates the weakened layer and reaches the lower layer structure (steel bar or complete concrete), the excitation device is interrupted when reaching the lower layer structure, and the breaking hammer 12 is lifted to separate from the road surface.

[0060] Step nine, after the first block of pre-crushing area completes crushing, the microwave heating device 18 scans and positions the second block of crushing unit to complete the pre-shift; 15s before the first unit completes crushing, the second unit microwave heating device 18 starts in advance; after the heating process of the second unit is completed, the vehicle moves to the second unit at a speed of 2m / min, and the resonance device is started to crush the concrete pavement layer of the second unit, to complete the closed-loop control chain of “pre-scanning positioning → microwave dynamic heating → frequency real-time calculation → crushing-transferring in parallel”, and realize the efficient, accurate and self-adaptive crushing process.

[0061] 1. Set up microwave-resonance energy coordination mechanism. Adopt directional microwave heating wall 1 (magnetron + waveguide array), induce microcrack network in the surface layer (0-8cm) of the concrete pavement layer through phase control focusing energy, so that the compressive strength of the area to be crushed is greatly reduced as a whole. Use the thermal expansion difference between steel bars and concrete to generate shear stress at the interface to cause interface peeling and block the continuous transmission of vibration energy to the lower layer. On the basis of microwave heating, use the resonance device to crush the weakened concrete layer, so as to achieve smaller vibration energy and propagation radius, reduce noise pollution, prolong the service life of the vibrator bearing and other components, and reduce maintenance cost.

[0062] 2. Self-adaptive frequency control technology. In the early stage of crushing, based on the real-time temperature data of the infrared thermal imager, the inherent frequency of the weakened concrete pavement layer is dynamically calculated through the internal algorithm of the system controller combined with the elastic modulus attenuation formula. In the later stage of crushing, the characteristic frequency signal is monitored through the acoustic emission signal device to judge the crushing state and control the depth error.

[0063] 3. Directional and accurate controllable crushing and multi-scene adaptation. Due to the exponential decay of microwave energy in concrete, a clear gradient temperature field is formed, the surface layer is accurately weakened, the lower structure is protected, and cracking of the lower layer is avoided during resonance. Through the whole process of “cutting and blocking, microwave heating, frequency calculation, resonance crushing, and work position transfer”, the closed-loop control chain of “pre-scanning-dynamic heating-real-time calculation-parallel transfer” is realized, the parameters are dynamically adjusted, and the crushing efficiency under different working conditions is improved. Secondly, through layered accurate crushing, the adaptability of the resonance crushing technology to the maintenance and modification of concrete pavement structures in highway sections, bridges, tunnels, airport runways and industrial parks and other scenes can be improved.

[0064] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the scope of the present application.

Claims

1. The adaptive crushing method of road concrete pavement based on microwave assisted resonance is characterized by: The concrete crushing device includes a microwave heating device, a resonance crushing device, and a data acquisition device. The microwave heating device is composed of multiple magnetrons and a speaker waveguide array. The resonance crushing device is composed of an exciter and a crushing hammer. The data acquisition device is composed of a GNSS positioning device, an acoustic emission sensor, and an infrared thermal imager. The specific crushing method is: using a microwave heating device to pre-treat the cut and divided crushing area, weakening the concrete layer through the heating effect of microwave radiation, and achieving the separation of the pavement layer; When the infrared thermal imager determines that the concrete in the heating area has reached the required temperature, the natural frequency of the concrete is calculated and the calculation result is fed back to the resonance crushing device. The resonance crushing device generates an excitation frequency to cause the pavement layer to vibrate and be crushed.

2. The road concrete pavement adaptive crushing method based on microwave assisted resonance according to claim 1 is characterized in that: The detailed steps of the crushing method are: Step 1: Use a milling machine to divide the pavement into 2m x 2m standard fragmentation units. A contour scanner mounted on a mobile platform travels along the road surface and constructs a 3D point cloud model. A visible light grid is projected onto the boundary of each fragmentation unit as a positioning reference to identify each fragmentation area. Step 2: The mobile platform moves to the center of the target crushing unit, and the microwave heating device is adjusted to be lowered to 20 cm from the pavement layer. The two-fold pyramid horn waveguide in the microwave heating device adopts an antenna array arrangement. The phase control of the horn waveguide array is used to achieve energy focusing, limiting the heating area to the target crushing unit. The horn waveguide array is adjusted to 0° and irradiated perpendicularly to the concrete surface; Step 3: Select the power parameters of the microwave heating device according to the strength grade of the pre-crushed concrete pavement; Step 4: The infrared thermal imager scans the surface temperature field of the pavement concrete in real time. The PID controller adjusts the output of the magnetron and controls the surface temperature of the pavement to rise to 100-150°C. The microwave power of the microwave heating device is dynamically adjusted based on the real-time feedback of the infrared temperature measurement to control the temperature gradient parameter to maintain ±10°C / m 2 ; Step 5: The acoustic emission sensor identifies the development of cracks on the pavement surface. The heating time lasts for 30-90 seconds. The crack width and density conditions are set. When the conditions are met, the heating is automatically terminated and the microwave heating device is retracted to its initial position. Step 6: Calculate the natural frequency of the pavement concrete and output the excitation frequency; Step 7: In the system controller, the frequency range of the data acquisition device is restricted to 15-25 Hz, and the crushing energy efficiency is monitored in real time using an acoustic emission sensor, and the microwave-resonance parameter combination is dynamically adjusted; Step 8: Set the excitation frequency of the resonant crushing device and the system controller controls the natural frequency of the concrete , drive the vibration system to run at variable frequency The hydraulic servo system adjusts the amplitude of the resonant hammer head according to the concrete strength level. When the vibration intensity is greater than 40Mpa, the amplitude is adjusted to 7-8mm, and when the intensity is less than 30Mpa, the amplitude is adjusted to 5-6mm. The crushing unit is crushed at a constant speed, and the vehicle speed is set to be inversely proportional to the amplitude, with a total range of 1-3m / min. The acoustic emission sensor monitors the characteristic frequency signal in real time, determines the crushing state, and controls the depth error. Step 9: After the first pre-crushing area is crushed, the microwave heating device scans and locates the second crushing unit to complete pre-displacement; 15 seconds before the first unit is crushed, the microwave heating device of the second unit is started in advance; after the heating process of the second unit is completed, the vehicle moves to the second unit at a speed of 2m / min, and the resonance device is started to crush the concrete pavement layer of the second unit.

3. The method for adaptive crushing of road concrete pavement based on microwave-assisted resonance according to claim 2, characterized in that: In step six, the calculation process of the system controller is: Step 1: Establish a temperature field model. The controller obtains the internal temperature of the concrete pavement layer through the heat conduction equation: ； ； Where, is the depth from the surface, is the microwave penetration depth, is the microwave frequency, is the dielectric loss factor of concrete; Step 2: Calculate the equivalent elastic modulus of the weakened concrete based on the empirical formula for elastic modulus attenuation: ； Where, The maximum temperature in the concrete pavement after heating. is the initial elastic modulus of concrete, is the elastic modulus of concrete after attenuation; Step 3: Solve the natural frequency. Simplify the cut concrete panel into a four-sided free thin plate model. The calculation formula for its natural frequency is: ； in, is the bending stiffness, is the mass per unit area, 、 is the panel size of the crushing unit.

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