Method for evaluating interlayer bonding state of asphalt pavement and related equipment

Abstract

The invention discloses a method and related equipment for evaluating the interlayer bonding state of an asphalt pavement, and belongs to the technical field of road engineering detection.The method comprises the steps that road information is obtained in a lossless mode through a bottom probing radar, then evaluation indexes of the interlayer bonding state of the road are obtained through radar data, and under the condition that interlayer bonding is poor and the thickness is small, the evaluation indexes of the interlayer bonding state of the road are obtained; according to the influence of interference coherence of electromagnetic waves on evaluation indexes, an auxiliary evaluation index is proposed to comprehensively evaluate the interlayer bonding state, and the accuracy of evaluating the interlayer bonding state of the asphalt pavement is improved through the combination of the two indexes.

Description

Technical Field

[0001] The invention belongs to the technical field of road engineering detection, and specifically relates to a method for evaluating the interlayer bonding state of an asphalt pavement and related equipment. Background Art

[0002] The interlayer bonding state of the pavement directly affects the integrity and performance of the pavement structure. When the interlayer bonding state is poor, the various structural layers of the pavement cannot work together, resulting in uneven stress distribution and a significant decrease in the pavement's bearing capacity. This condition will accelerate the development of fatigue damage, causing cracks, rutting and other diseases, which will not only reduce driving comfort and safety, but also shorten the service life of the pavement and increase maintenance and repair costs. At the same time, poor interlayer bonding will also cause water penetration, accelerating structural damage under the action of freeze-thaw cycles.

[0003] At present, the evaluation of interlayer bonding state of roads mainly relies on traditional testing methods such as core drilling method, peeling test method, pull-out test and shear test, which are evaluated by obtaining interlayer mechanical parameters (interlayer shear strength, interlayer tensile strength, etc.). These traditional methods have obvious limitations: damage to the road surface; low detection efficiency and limited range; results are easily affected by the environment; and it is impossible to obtain continuous interlayer state information. Summary of the invention

[0004] The present invention provides a method for evaluating the interlayer bonding state of asphalt pavement and related equipment, which solves the problems that traditional detection methods cause damage to the pavement, have low detection efficiency, limited range, are easily affected by the environment, and cannot obtain continuous interlayer state information.

[0005] To achieve the above object, the present invention provides the following technical solutions: A method for evaluating the bonding state between asphalt pavement layers, comprising: Radar data to collect road information on asphalt pavement; Preprocess the collected radar data; Based on the preprocessed radar data, the evaluation index of the bonding state between road layers is obtained; Obtain the relationship between the two-way travel time of the upper and lower interfaces between the layers of the asphalt pavement and one cycle of the detected electromagnetic wave; The interlayer bonding state of asphalt pavement is evaluated by combining the evaluation index of interlayer bonding state of road and the relationship between the two-way travel time of the upper and lower interfaces between the layers of asphalt pavement and one cycle of the detected electromagnetic wave. Among them, iron sheets are placed at the starting point of the asphalt pavement collection road.

[0006] Preferably, when collecting radar data of asphalt pavement road information, it is necessary to ensure that the road surface is dry, and then perform ground penetrating radar detection on the asphalt pavement section to be detected to collect road information.

[0007] Preferably, the step of preprocessing the collected radar data is specifically as follows: The collected radar data are sequentially subjected to interference suppression, inverse short-time Fourier transform, background filtering, data gain and time zero correction steps.

[0008] Preferably, based on the preprocessed radar data, the evaluation index for obtaining the interlayer bonding state of the road is specifically: Based on the total reflection peak at the starting iron sheet position in the data, the first peak value of the electromagnetic wave entering the road surface and the peak value of the reflection at the interlayer interface at each detection point on the road are detected, and then combined with the A-scan waveform characteristics of each detection point, the evaluation index of the interlayer bonding state of the road is obtained.

[0009] Preferably, the calculation formula of the evaluation index is:

[0010] in is the peak value of the total reflection wave at the starting iron sheet position, For each detection point, the first peak value of the wave entering the road surface, For each detection point, the peak value between layers is is the distance between the target interface and the ground, is the depth correction function.

[0011] Preferably, the method for obtaining the depth correction function is: An iron sheet is added underneath the Marshall specimens at different heights and buried in the soil. The echo data of the iron sheet at different heights are collected by radar scanning, and the depth correction function is fitted.

[0012] Preferably, the interlayer bonding state of the asphalt pavement is evaluated by combining the evaluation index of the interlayer bonding state of the road and the relationship between the two-way travel time of the upper and lower interfaces between the layers of the asphalt pavement road and one cycle of the detected electromagnetic wave. Specifically: when , evaluation index When ≤a, the interlayer bonding is good, the evaluation index When a, the interlayer bonding is normal; when , defined as poor interlayer bonding; when , and there are two peaks at this position, which is defined as severe poor interlayer bonding. in, is an evaluation index of the bonding state between road layers. To detect the time of one cycle of electromagnetic wave, is the two-way travel time of the upper and lower interfaces between layers, and a is In 0- The boundary value between good and general interlayer bonding conditions.

[0013] A system for evaluating the bonding state between asphalt pavement layers. Acquisition module: used to collect radar data of asphalt road information; Preprocessing module: used to preprocess the collected radar data; The first acquisition module is used to obtain the evaluation index of the bonding state between road layers based on the preprocessed radar data; The second acquisition module is used to obtain the relationship between the two-way travel time of the upper and lower interfaces between the layers of the asphalt pavement and one cycle of the detection electromagnetic wave; Evaluation module: used to evaluate the interlayer bonding state of asphalt pavement by combining the evaluation index of interlayer bonding state of road and the relationship between the two-way travel time of the upper and lower interfaces between the layers of the asphalt pavement and one cycle of the detected electromagnetic wave; Among them, iron sheets are placed at the starting point of the asphalt pavement collection road.

[0014] A computer device comprises a memory, a processor and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of a method for evaluating the bonding state between asphalt pavement layers are implemented.

[0015] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of a method for evaluating the bonding state between asphalt pavement layers.

[0016] Compared with the prior art, the present invention has the following beneficial effects: the present invention provides a method for evaluating the interlayer bonding state of asphalt pavement, firstly, road information is non-destructively acquired through bottom-penetrating radar, and then evaluation indicators of the interlayer bonding state of the road are acquired through radar data, and then, considering the influence of the interference coherence of electromagnetic waves on the evaluation indicators when the thickness of the interlayer defect is very small, an auxiliary evaluation indicator is proposed to conduct a comprehensive evaluation of the interlayer bonding state, and the accuracy of the evaluation of the interlayer bonding state of the asphalt pavement is improved by the combination of the two indicators.

[0017] Furthermore, the evaluation index is based on the principle of reflection coefficient and the propagation process of electromagnetic waves in the asphalt surface layer, and comprehensively considers the influence of different electromagnetic wave emission intensities and different asphalt surface material properties, making the evaluation index more universal. Compared with the existing technology, this evaluation index can more accurately reflect the size of the interlayer interface reflection coefficient, and thus can more accurately reflect the difference in dielectric constants between the upper and lower layers at the interlayer interface.

[0018] A depth correction function is proposed to effectively solve the problem of the target interface bringing different depths to the index. Through the correction of this function, the evaluation results are comparable under different depth conditions, which improves the scope of application of the evaluation method. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A flow chart of a method for evaluating the interlayer bonding state of an asphalt pavement according to the present invention; Figure 2 The present invention is a system block diagram for evaluating the interlayer bonding state of asphalt pavement. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0023] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0024] like Figure 1 As shown, the present invention provides a method for evaluating the bonding state between asphalt pavement layers, comprising: S101 collects radar data of asphalt road information; S102 pre-processes the collected radar data; S103 obtains an evaluation index of the bonding state between road layers based on the preprocessed radar data; S104 obtains the relationship between the two-way travel time of the upper and lower interfaces between the layers of the asphalt pavement road and one cycle of the detection electromagnetic wave; S105 evaluates the interlayer bonding state of the asphalt pavement by combining the evaluation index of the interlayer bonding state of the road and the relationship between the two-way travel time of the upper and lower interfaces between the layers of the asphalt pavement road and one cycle of the detection electromagnetic wave; Among them, iron sheets are placed at the starting point of the asphalt pavement collection road.

[0025] The detailed steps are: Step 1: Field data collection Before collecting data, ensure that the test section is dry and there has been no rain in the test area in recent days.

[0026] At the starting point of the detection section, an iron sheet needs to be placed to mark the starting point in order to obtain the antenna total reflection wave from the iron sheet. Then, a ground penetrating radar test is carried out on the asphalt road section to be tested to collect road information.

[0027] Step 2: Data Preprocessing In the radar data processing software, the collected raw data are subjected to interference suppression, inverse short-time Fourier transform, background filtering, data gain, and time zero correction steps in sequence to eliminate clutter and ensure the standardization and effectiveness of the data.

[0028] Step 3: Calculation of evaluation indicators The processed radar data is exported in the radar data processing software, and the total reflection peak at the starting point iron sheet position in the data is recorded as A0, the first peak value of the electromagnetic wave entering the road surface at each detection point on the detection road is recorded as A1 of the point, and the peak value of the reflection at the interlayer interface is recorded as A2 of the point. Based on these echo data, the evaluation index r of the point is calculated, and (Time difference between the upper and lower interfaces between layers). At the same time, combined with the A-scan waveform characteristics of each detection point, a comprehensive evaluation of the interlayer bonding state of the road surface is carried out.

[0029] Core evaluation indicators The calculation formula is as follows:

[0030] in is the peak value of the total reflection wave at the starting iron sheet position, For each detection point, the first peak value of the wave entering the road surface, For each detection point, the peak value between layers is is the distance between the target interface and the ground, is the depth correction function.

[0031] The theoretical derivation process of this evaluation index is as follows: In the actual detection process, in order to ensure the safe distance between the equipment during the detection process, the antenna is generally at a certain height above the ground. Assume that the antenna height above the ground is , the interlayer position to be detected is on the road surface Because the dielectric constant of asphalt mixture does not fluctuate much in dry conditions, the asphalt surface layer is assumed to be a uniform medium, and the attenuation constant in the asphalt mixture is assumed to be , the attenuation constant in air is Consider the electromagnetic wave Through the law of energy conservation, we can get the incident wave energy of electromagnetic waves entering the road surface from the attenuation in the high air layer:

[0032] Then after The attenuation in the asphalt mixture of thickness reaches the target interface, and the energy of the electromagnetic wave is:

[0033] Assume that the reflection coefficient of the target interface is , after being reflected by the target interface, the electromagnetic wave energy at this time is:

[0034] Then the electromagnetic wave passes through The attenuation inside the asphalt mixture reaches the ground and then transmits out of the ground. Assuming that the transmission coefficient of the asphalt mixture to the air is , the energy of the electromagnetic wave transmitted through the ground at this time is:

[0035] Last passed The attenuation in the air becomes the attenuation in the radar receiver. , that is:

[0036] Here we can obtain the reflection coefficient at the interlayer position based on the echo data we collected:

[0037] Considering that actual radar data will perform gain processing on radar echo data during the processing stage, it is assumed that its gain function is ,in is the propagation time of the electromagnetic wave from entering the road surface, then the actual reflection coefficient is:

[0038] Since we assume the asphalt surface to be a homogeneous medium, the gain function can be converted to , For depth, is the speed of electromagnetic waves in asphalt mixture, so the reflection coefficient here is:

[0039] Since the dielectric constant of asphalt mixture is relatively stable under dry conditions, the refractive index here is and can also be approximated as a constant, so the second half of the above formula can be approximated as a constant. The relevant function can be simplified to Therefore, this indicator directly reflects the magnitude of the interlayer bad interface reflection coefficient, that is, the dielectric constant difference of the target interface. The larger the value, the greater the difference between the dielectric constant between the interlayer and the asphalt layer, indicating that the interlayer bonding state at this interlayer position is worse.

[0040]

[0041] Evaluation index correction function It is used to eliminate the influence of depth on the evaluation results and ensure that the evaluation index can be applied to any depth. The value is not only affected by the reflection coefficient of the target interface, but also by the dual effects of electromagnetic wave attenuation and data processing gain due to the change of interface depth, which leads to changes in the measured value. This function needs to be obtained through indoor or field tests. The specific method is to add a piece of iron under the Marshall specimens of different heights and bury them in the soil, use radar scanning to collect the echo data of the iron sheet at different heights, and fit the function .

[0042] Step 4: Evaluation Metrics and waveform characteristics Since the actual thickness of interlayer bonding defects is usually relatively small, we found that when the spacing between interlayer defects is very small, electromagnetic waves will interfere with each other when propagating between layers. The indicator is not only related to the difference in dielectric constant between layers, but also affected by the poor thickness between layers. So another evaluation indicator is proposed here , which is the two-way travel time of the upper and lower interfaces between layers, and also corresponds to the distance between the two negative peaks in the waveform to ensure the accuracy of the evaluation method. The value is one cycle of the radar detection center frequency, and the calculation formula is as follows:

[0043] in To detect the time of one cycle of electromagnetic wave, To detect the center frequency of electromagnetic waves.

[0044] (1) When

[0045] As the thickness of the thin layer increases, the path difference increases, and the superimposed reflected waves gradually produce a certain phase difference, but Before reaching half a period, coherent interference still dominates, echo data increases, and evaluation indicators Increase, and The interlayer thickness has not yet reached the critical overlap frequency, so this interval The wave will not increase with the increase of thickness, but will remain stable at At this time, the interlayer waveform has an obvious peak, and as the interlayer defect thickness increases, the peak value also increases, but the distance between the two negative peaks corresponding to the upper and lower interfaces is It will not change.

[0046] (2) When

[0047] As the thickness of the air layer continues to increase ( When the path difference is greater than half a period but less than one period, the phase difference between the reflected waves increases further; as the thickness increases, the path difference gradually approaches one wavelength, and at this time the reflected wave phase gradually tends to be superimposed again. However, due to the periodic change of the phase, some reflected signals will interfere destructively. At this stage, the evaluation index On the contrary, it decreases with the increase of thickness, and the minimum value is when the upper and lower layers are separated. This is because phase interference causes the energy of some reflected signals to cancel out. The sum will increase with the increase of thickness. At this time, the interlayer waveform feature still has an obvious peak, and as the interlayer defect thickness increases, the value of the peak decreases, and the distance between the two negative peaks increases.

[0048] (3) When

[0049] Evaluation indicators There will be a slight upward trend at the beginning, and finally stabilize as the thickness increases. At this time, you can see that the obvious single peak will gradually turn into a double peak until the upper interface is completely separated.

[0050] Step 5: Evaluation system There are various complex situations of interlayer defects, but the good interlayer situation is relatively simple, that is, there are no impurities between the layers, or there are only related substances for interlayer bonding between the layers. The relevant indicators are and Less than a. The value of a is related to the detection equipment and data processing method. The method of obtaining the value a of your own equipment can be obtained through indoor tests and field verification. A certain number of core samples with good and bad interlayers can be measured through indoor tests to determine the value a, or through actual detection section data, a certain number of points located at the boundary between good and bad interlayers are selected according to waveform characteristics to take cores for verification and determine the value a.

[0051] Combining the previous two evaluation indicators, the following evaluation system is proposed: The collected data are The size of the data is divided into three categories according to the following intervals.

[0052] when

[0053] Evaluation indicators When ≤a, the interlayer bonding is good, the evaluation index When >a, the interlayer bonding is normal.

[0054] when

[0055] Poor interlayer adhesion when , and there are two peaks at this position: Directly defined as severe poor interlayer adhesion like Figure 2 As shown, the present invention provides a system for evaluating the bonding state between asphalt pavement layers, comprising: Acquisition module: used to collect radar data of asphalt road information; Preprocessing module: used to preprocess the collected radar data; The first acquisition module is used to obtain the evaluation index of the bonding state between road layers based on the preprocessed radar data; The second acquisition module is used to obtain the relationship between the two-way travel time of the upper and lower interfaces between the layers of the asphalt pavement and one cycle of the detection electromagnetic wave; Evaluation module: It is used to evaluate the interlayer bonding state of asphalt pavement by combining the evaluation index of the interlayer bonding state of the road and the relationship between the two-way travel time of the upper and lower interfaces between the layers of the asphalt pavement and one cycle of the detected electromagnetic wave. Among them, iron sheets are placed at the starting point of the asphalt pavement collection road.

[0056] A terminal device is provided in one embodiment of the present invention. The terminal device of this embodiment includes: a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps in the above-mentioned method embodiments are implemented. Alternatively, when the processor executes the computer program, the functions of the modules / units in the above-mentioned device embodiments are implemented.

[0057] The computer program may be divided into one or more modules / units, and the one or more modules / units are stored in the memory and executed by the processor to accomplish the present invention.

[0058] The terminal device may be a computing device such as a desktop computer, a notebook, a PDA, a cloud server, etc. The terminal device may include, but is not limited to, a processor and a memory.

[0059] The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0060] The memory may be used to store the computer program and / or module, and the processor implements various functions of the terminal device by running or executing the computer program and / or module stored in the memory and calling the data stored in the memory.

[0061] If the module / unit integrated in the terminal device is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, the steps of the above-mentioned various method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electric carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0062] Although the embodiments of the present invention are described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments and application fields, and the above-mentioned specific embodiments are only illustrative and instructive, rather than restrictive. Under the guidance of the specification, a person skilled in the art can also make many forms without departing from the scope of protection of the claims of the present invention, all of which belong to the scope of protection of the present invention.

Claims

1. A method for evaluating the interlayer bonding state of an asphalt pavement, characterized in that: include: Radar data to collect road information on asphalt pavement; Preprocess the collected radar data; Based on the preprocessed radar data, the evaluation index of the bonding state between road layers is obtained; Obtain the relationship between the two-way travel time of the upper and lower interfaces between the layers of the asphalt pavement and one cycle of the detected electromagnetic wave; The interlayer bonding state of asphalt pavement is evaluated by combining the evaluation index of interlayer bonding state of road and the relationship between the two-way travel time of the upper and lower interfaces between the layers of asphalt pavement and one cycle of the detected electromagnetic wave. Among them, iron sheets are placed at the starting point of the asphalt pavement collection road.

2. A method for evaluating the interlayer bonding state of an asphalt pavement according to claim 1, characterized in that: When collecting radar data of asphalt pavement information, make sure the road surface is dry, and then perform ground penetrating radar inspection on the asphalt pavement section to be inspected to collect road information.

3. The method for evaluating the interlayer bonding state of asphalt pavement according to claim 1, characterized in that: The specific steps for preprocessing the collected radar data are: The collected radar data are sequentially subjected to interference suppression, inverse short-time Fourier transform, background filtering, data gain and time zero correction steps.

4. The method for evaluating the interlayer bonding state of asphalt pavement according to claim 1, characterized in that: Based on the preprocessed radar data, the evaluation index of the interlayer bonding state of the road is obtained as follows: Based on the total reflection peak at the starting iron sheet position in the data, the first peak value of the electromagnetic wave entering the road surface and the peak value of the reflection at the interlayer interface at each detection point on the road are detected, and then combined with the A-scan waveform characteristics of each detection point, the evaluation index of the interlayer bonding state of the road is obtained.

5. A method for evaluating the interlayer bonding state of an asphalt pavement according to claim 4, characterized in that: The calculation formula of the evaluation index is: in is the peak value of the total reflection wave at the starting iron sheet position, For each detection point, the first peak value of the wave entering the road surface, For each detection point, the peak value between layers is is the distance between the target interface and the ground, is the depth correction function.

6. A method for evaluating the interlayer bonding state of asphalt pavement according to claim 5, characterized in that: The method to obtain the depth correction function is: An iron sheet is added underneath the Marshall specimens at different heights and buried in the soil. The echo data of the iron sheet at different heights are collected by radar scanning, and the depth correction function is fitted.

7. The method for evaluating the interlayer bonding state of asphalt pavement according to claim 1, characterized in that: The interlayer bonding state of the asphalt pavement is evaluated by combining the evaluation index of the interlayer bonding state of the road and the relationship between the two-way travel time of the upper and lower interfaces between the layers of the asphalt pavement and one cycle of the detected electromagnetic wave. Specifically: when , evaluation index When ≤a, the interlayer bonding is good, the evaluation index When a, the interlayer bonding is normal; when , defined as poor interlayer bonding; when , and there are two peaks at this position, which is defined as severe poor interlayer bonding. in, is an evaluation index of the bonding state between road layers. To detect the time of one cycle of electromagnetic wave, is the two-way travel time of the upper and lower interfaces between layers, and a is In 0- The boundary value between good and general interlayer bonding conditions.

8. A system for evaluating the bonding state between asphalt pavement layers, characterized in that: include: Acquisition module: used to collect radar data of asphalt road information; Preprocessing module: used to preprocess the collected radar data; The first acquisition module is used to obtain the evaluation index of the bonding state between road layers based on the preprocessed radar data; The second acquisition module is used to obtain the relationship between the two-way travel time of the upper and lower interfaces between the layers of the asphalt pavement and one cycle of the detection electromagnetic wave; Evaluation module: used to evaluate the interlayer bonding state of asphalt pavement by combining the evaluation index of interlayer bonding state of road and the relationship between the two-way travel time of the upper and lower interfaces between the layers of the asphalt pavement and one cycle of the detected electromagnetic wave; Among them, iron sheets are placed at the starting point of the asphalt pavement collection road.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method for evaluating the interlayer bonding state of an asphalt pavement as described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of a method for evaluating the interlayer bonding state of an asphalt pavement as described in any one of claims 1 to 7 are implemented.

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