A method and system for detecting damage to concrete pavement

Abstract

This application relates to the field of concrete testing technology, specifically to a method and system for detecting damage to concrete pavements. The method includes: acquiring ultrasonic signals from each ultrasonic test of the concrete pavement; defining the time interval between each ultrasonic test and the previous ultrasonic test as the interval before each ultrasonic test; acquiring the temperature and humidity at each moment within the interval; and the test temperature for each ultrasonic test; calculating the signal anomaly degree of each ultrasonic test; calculating the relative temperature-humidity ratio, relative temperature difference, and cumulative anomaly; calculating the environmental correlation and cumulative damage degree of each ultrasonic test; obtaining the evaluation coefficient for each ultrasonic test; and evaluating the damage to the concrete pavement. This application can eliminate interference caused by the uneven mixing of the concrete itself within the concrete pavement, improving the accuracy of detecting freeze-thaw cycle damage within the concrete pavement, and enabling sensitive detection of early, minute freeze-thaw damage within the concrete pavement.

Description

Technical Field

[0001] This application relates to the field of concrete testing technology, specifically to a method and system for detecting damage to concrete pavements. Background Technology

[0002] Concrete pavements gradually degrade in structural performance due to long-term exposure to complex environments and dynamic loads. Among these, freeze-thaw cycles are one of the main threats to concrete structures in cold regions. The mechanism of freeze-thaw damage lies in the fact that when water in the pores of concrete freezes and expands at low temperatures, it generates internal stress, leading to the initiation and propagation of microcracks. When the temperature rises, the ice melts, and the cracks cannot be completely closed. After multiple cycles, the damage accumulates, eventually leading to serious consequences such as decreased concrete strength and surface spalling.

[0003] Because concrete is a mixture of various materials, there is an uneven mixing phenomenon. When ultrasonic testing concrete pavement, this uneven mixing will also complicate the ultrasonic wave propagation path, making it easy to mask the weak signal changes caused by early freeze-thaw damage, such as microcracks. This will interfere with the detection of early freeze-thaw cycle damage, affect the accuracy of detecting freeze-thaw cycle damage inside the concrete pavement, and thus fail to detect early freeze-thaw cycle damage inside the concrete pavement in a timely manner. Summary of the Invention

[0004] To address the aforementioned technical problems, a method and system for detecting damage to concrete pavements are provided to resolve existing issues.

[0005] The solution to the technical problem of this application is to provide a method and system for detecting damage to concrete pavements, including the following steps:

[0006] In a first aspect, embodiments of this application provide a method for detecting damage to concrete pavements, the method comprising the following steps:

[0007] The ultrasonic signals of the concrete pavement during each ultrasonic test are obtained; the time period between the time before each ultrasonic test and the time after the previous ultrasonic test is recorded as the interval period before each ultrasonic test; the temperature and humidity at each moment within the interval period are obtained; and the average temperature within the corresponding time period of the ultrasonic signal of each ultrasonic test is recorded as the test temperature.

[0008] Curve fitting is performed on all signal amplitudes in the ultrasonic signal. The overlap of the integral area of ​​the fitted curve between each ultrasonic test and the previous ultrasonic test is analyzed, and the signal anomaly degree of each ultrasonic test is calculated.

[0009] The relative temperature-humidity ratio is calculated based on the average level of all humidity levels and the average level of all temperature troughs within the specified interval; the relative temperature difference is calculated based on the difference in detection temperature between two adjacent ultrasonic tests; and the cumulative abnormality of each ultrasonic test is obtained based on the signal abnormality of each ultrasonic test and all previous ultrasonic tests.

[0010] The environmental correlation of each ultrasound test is calculated by comparing the relative temperature-humidity ratio and relative temperature difference of each ultrasound test and all previous ultrasound tests with the cumulative abnormality.

[0011] The dispersion and trend of the cumulative anomalies in each ultrasonic test and all previous ultrasonic tests are analyzed. Combined with environmental correlation, the cumulative damage degree of each ultrasonic test is determined. Combined with the order of each ultrasonic test, the evaluation coefficient of each ultrasonic test is obtained to evaluate the damage to the concrete pavement.

[0012] Preferably, the calculation of the signal abnormality for each ultrasound detection includes:

[0013] Calculate the area under the integral of the fitted curve corresponding to the ultrasonic signal for each ultrasonic test;

[0014] Calculate the area of ​​the overlapping region under the fitted curve between each ultrasound examination and the previous ultrasound examination, and record it as the overlapping area.

[0015] Calculate the sum of the integrated areas of each ultrasound detection and the previous ultrasound detection, and use the difference between the sum and a preset multiple of the overlapping area as the signal anomaly degree of each ultrasound detection.

[0016] Preferably, the calculation of the relative temperature-humidity ratio includes:

[0017] Calculate the average humidity at all times within the specified interval before each ultrasound examination, and record it as the average humidity.

[0018] Obtain the temperature troughs at all times within the specified interval, and record the average value of all troughs as the average low temperature.

[0019] The ratio between the average humidity and the average low temperature is used as the relative temperature-humidity ratio for each ultrasonic test.

[0020] Preferably, the relative temperature difference is the difference between the detection temperature of each ultrasonic test and the previous ultrasonic test.

[0021] Preferably, the cumulative abnormality is the sum of the signal abnormality of each ultrasound detection and all previous ultrasound detections.

[0022] Preferably, the calculation of the environmental relevance of each ultrasound examination includes:

[0023] The correlation between the relative temperature difference of each ultrasound examination and all previous ultrasound examinations and the cumulative abnormality is calculated and denoted as the first correlation degree.

[0024] The correlation between the relative temperature and humidity ratio of each ultrasound examination and all previous ultrasound examinations and the cumulative abnormality is calculated and denoted as the second correlation degree.

[0025] The environmental relevance is the product of the first relevance and the second relevance.

[0026] Preferably, determining the cumulative damage for each ultrasound examination includes:

[0027] Calculate the dispersion of the cumulative abnormality for each ultrasound examination and all previous ultrasound examinations;

[0028] The cumulative abnormality of each ultrasound examination and all previous ultrasound examinations is used to form an abnormality sequence. The first-order difference sequence of the abnormality sequence is calculated, and the proportion of negative elements in the first-order difference sequence is counted.

[0029] Calculate the product of the degree of dispersion and the degree of environmental correlation; use the ratio of the product to the percentage as the cumulative damage degree for each ultrasound examination.

[0030] Preferably, obtaining the evaluation coefficient for each ultrasound examination includes: counting the number of each ultrasound examination and all previous ultrasound examinations; and using the ratio of the cumulative damage to the number of examinations as the evaluation coefficient for each ultrasound examination.

[0031] Preferably, the assessment of damage to the concrete pavement includes: obtaining a segmentation threshold for the assessment coefficient of each ultrasonic test and all previous ultrasonic tests; if the assessment coefficient of multiple consecutive ultrasonic tests is greater than the segmentation threshold, then freeze-thaw cycle damage exists inside the concrete pavement; otherwise, freeze-thaw cycle damage does not exist inside the concrete pavement.

[0032] Secondly, embodiments of this application also provide a concrete pavement damage detection system, including a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor executes the computer program to implement the steps of any of the above-described concrete pavement damage detection methods.

[0033] This application has at least the following beneficial effects:

[0034] This application calculates the signal anomaly degree for each ultrasonic test by curve fitting of all signal amplitudes and analyzing the non-overlapping integral areas under the fitted curves between two adjacent ultrasonic tests. The beneficial effect is that it considers the signal fluctuation differences between two ultrasonic tests, reflecting significant changes in the internal structural damage of the concrete pavement, capturing waveform distortion caused by microcracks resulting from early freeze-thaw damage, and thus eliminating the influence of the uneven mixing and impurities of the concrete itself on the ultrasonic signal. Furthermore, it calculates the relative temperature-humidity ratio and relative temperature difference, which is beneficial because it considers the coupled changes in temperature and humidity, as well as the differences in temperature difference, reflecting the fluctuations in environmental factors. Secondly, it calculates the cumulative anomaly amount for each ultrasonic test, which is beneficial because it considers the cumulative internal damage of the concrete pavement before each ultrasonic test, amplifying minute but significant anomalies. The study focuses on the characteristics of continuous freeze-thaw damage. It calculates the environmental correlation of each ultrasonic test, which is beneficial because it considers the impact of environmental changes on ultrasonic signals, reflecting the correlation between environmental factors and internal damage changes in concrete pavements, thus enhancing the sensitivity of identifying freeze-thaw cycle damage characteristics in concrete pavements. It also determines the cumulative damage degree of each ultrasonic test, which is beneficial because it considers the progressive damage accumulation process caused by freeze-thaw cycles in concrete, reflecting the possibility of freeze-thaw cycle damage in concrete pavements. Furthermore, it combines the order of each ultrasonic test to obtain the evaluation coefficient for each test, assessing the damage to the concrete pavement. This is beneficial because it eliminates interference caused by the uneven mixing of the concrete itself, improving the accuracy of detecting freeze-thaw cycle damage within the concrete pavement, and enabling sensitive capture of early, minute freeze-thaw damage within the concrete pavement. Attached Figure Description

[0035] The following description, in conjunction with the accompanying drawings, provides a more detailed explanation of a concrete pavement damage detection method of this application.

[0036] Figure 1 A flowchart illustrating the steps of a concrete pavement damage detection method provided in this application embodiment;

[0037] Figure 2 A schematic diagram of an ultrasonic signal provided in an embodiment of this application;

[0038] Figure 3 This is a schematic diagram of temperature changes within a time interval provided in the embodiments of this application;

[0039] Figure 4 This is a schematic diagram of humidity changes over time intervals provided in an embodiment of this application;

[0040] Figure 5 A flowchart illustrating the steps of the method for obtaining the environmental correlation of each ultrasound examination provided in this application embodiment;

[0041] Figure 6 A flowchart illustrating the steps of the method for obtaining the evaluation coefficient for each ultrasound examination provided in this application embodiment;

[0042] Figure 7 This is a schematic diagram illustrating the changes in the evaluation coefficients for all ultrasound examinations provided in the embodiments of this application. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description of a concrete pavement damage detection method and system proposed in this application, in conjunction with the accompanying drawings and implementation examples, is provided. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0045] Please see Figure 1 The diagram illustrates a flowchart of a concrete pavement damage detection method according to an embodiment of this application, which includes the following steps:

[0046] Step 1: Obtain the ultrasonic signals of the concrete pavement during each ultrasonic test; record the time period between each ultrasonic test and the previous ultrasonic test as the interval period before each ultrasonic test, and obtain the temperature and humidity at each moment within the interval period; and record the average temperature within the corresponding duration of the ultrasonic signals of each ultrasonic test as the test temperature.

[0047] Concrete used for highway pavements generally requires high strength, durability, corrosion resistance, flexural strength, and abrasion resistance. In addition, it must possess good stability and be unaffected by climatic conditions. However, concrete pavements in permafrost environments are often subjected to severe freeze-thaw cycle damage due to climatic influences. Freeze-thaw cycles are a natural phenomenon caused by changes in external temperature. Above zero degrees Celsius, frost on the surface of the structure melts into water droplets that penetrate into the structure. When the external temperature drops, the water inside the structure undergoes a liquid-to-solid transformation, causing volume changes and leading to frost heave damage. Ultimately, this results in internal cracks and damage, affecting the mechanical properties of the structure. Therefore, the damage to concrete pavements caused by freeze-thaw cycles is a dynamic and cumulative process.

[0048] Therefore, an ultrasonic sensor is placed on one side of the concrete pavement. The ultrasonic sensor emits ultrasonic waves into the concrete pavement through a signal transmitter and receives the reflected ultrasonic waves. The ultrasonic signals are collected, and the concrete pavement is subjected to multiple ultrasonic tests to obtain the ultrasonic signals at each test.

[0049] In this embodiment, the excitation frequency of the signal transmitter is set to 50kHz and the excitation voltage is set to 5V to emit ultrasonic waves. The duration of each ultrasonic test is set to 10s. Since the diurnal temperature range is large in the climate where the experiment was conducted, the concrete pavement is tested once a day. As for other implementation methods, the implementer can set the parameters according to the actual situation.

[0050] Furthermore, by using temperature and humidity sensors at highway monitoring points, the data collected... After the first ultrasound examination until the [number]th Temperature and humidity at different times between ultrasound examinations, and the first After the first ultrasound examination until the [number]th The time interval between each ultrasound examination is denoted as the interval period, and the number of ultrasound examinations is obtained. Temperature and humidity at each time point within the specified interval before the ultrasound examination.

[0051] In this embodiment, the temperature and humidity sensor collects data at a time interval of 1 minute. In other implementation methods, the implementer can set the time interval according to the actual situation.

[0052] The temperature sensor is used to obtain the temperature at each moment within the corresponding time period of the ultrasonic signal for each ultrasonic test. The average temperature at all moments within the corresponding time period is recorded as the test temperature, that is, the average temperature at all moments within 10 seconds when performing ultrasonic testing.

[0053] All collected data are normalized. In this embodiment, the maximum and minimum value method is used for normalization. The maximum and minimum value method is a well-known technique and will not be described in detail here. As other implementation methods, implementers can use other methods of existing technology, such as the Z-score method. This embodiment does not impose any special restrictions on this.

[0054] A schematic diagram of the ultrasonic signal provided in the embodiments of this application is shown below. Figure 2 As shown; a schematic diagram of temperature changes within the time interval is shown below. Figure 3 As shown in the diagram, the humidity changes over the time intervals are illustrated below. Figure 4 As shown; in this embodiment, 15 ultrasound examinations are taken as an example. Therefore, there is an interval between two adjacent ultrasound examinations. Thus, there are a total of 14 intervals between the 15 ultrasound examinations.

[0055] Thus, the ultrasonic signal and detection temperature during each ultrasonic test are obtained, as well as the temperature and humidity at each time interval before each ultrasonic test.

[0056] Step 2: Perform curve fitting on all signal amplitudes in the ultrasonic signal, analyze the overlap of the integral area of ​​the fitted curve between each ultrasonic test and the previous ultrasonic test, and calculate the signal anomaly degree of each ultrasonic test.

[0057] When concrete suffers freeze-thaw cycle damage, it undergoes repeated freeze-thaw cycles, resulting in numerous internal cracks and even serious defects such as surface cracking, peeling, and powdering. Therefore, it is essential to detect freeze-thaw cycle damage within the concrete pavement structure to ensure the stability and service life of the concrete pavement.

[0058] The fluctuation of ultrasonic signals can reflect the damage characteristics inside concrete pavement. However, the non-uniformity of concrete mixing and the presence of impurities inside the concrete can also affect the fluctuation of ultrasonic signals, thus interfering with the detection of damage inside concrete pavement.

[0059] Secondly, after concrete solidifies, the material distribution within its internal structure has a certain stability. This results in relatively fixed reflection and refraction phenomena during ultrasonic testing, leading to a relatively stable peak distribution between different ultrasonic tests. However, internal damage to concrete is unstable and deepens over time, resulting in differences in ultrasonic signals between different tests. Furthermore, damage can cause energy loss in ultrasonic signals. For example, moisture or other impurities present at the damaged area can absorb ultrasonic energy, causing the ultrasonic signal to gradually attenuate during propagation.

[0060] Based on the above analysis, the signal anomaly degree is calculated by measuring the difference in ultrasound signals between two consecutive ultrasound examinations, in order to assess the abnormal fluctuations in the ultrasound signals. Specifically:

[0061] Curve fitting is performed on all signal amplitudes in the ultrasonic signals of each ultrasonic test to obtain the fitted curve, and the area of ​​the integral of the fitted curve is calculated.

[0062] In this embodiment, a polynomial fitting algorithm is used for curve fitting. The polynomial fitting algorithm is a well-known technique and will not be described in detail here.

[0063] Calculate the area of ​​the overlapping region under the fitted curve between each ultrasound examination and the previous ultrasound examination, and record it as the overlapping area.

[0064] In this embodiment, the Monte Carlo method is used to calculate the area of ​​the overlapping region. The Monte Carlo method is a well-known technique and will not be described in detail here.

[0065] Calculate the sum of the integral areas of each ultrasound detection and the previous ultrasound detection, and use the difference between the sum and a preset multiple of the overlapping area as the signal anomaly degree of each ultrasound detection.

[0066] In this embodiment, since the overlapping area is added twice when calculating the sum, the overlapping area needs to be subtracted when calculating the non-overlapping integral area. Therefore, the preset multiplier is 2. The formula for calculating the signal abnormality of each ultrasound detection is as follows:

[0067]

[0068] in, Let k be the signal anomaly degree of the k-th ultrasound detection. Let be the integrated area of ​​the k-th ultrasound test. The integral area is the area of ​​the (k-1)th ultrasound examination. The area of ​​the overlapping region under the fitted curve between the (k-1)th and kth ultrasound detections is called the overlap area.

[0069] It should be noted that, since internal damage causes the energy of ultrasonic signals to attenuate and be lost, the larger the area of ​​the non-overlapping part under the fitting curve of the ultrasonic signals from two adjacent ultrasonic tests, the greater the signal anomaly, indicating that the damage changes in the internal structure of the concrete pavement are more significant.

[0070] Thus, the signal abnormality level of each ultrasound examination is obtained.

[0071] Step 3: Calculate the relative temperature-humidity ratio based on the average level of all humidity levels and the average level of all temperature troughs within the specified interval; calculate the relative temperature difference based on the temperature difference between two adjacent ultrasonic tests; obtain the cumulative abnormality of each ultrasonic test based on the signal abnormality of each ultrasonic test and all previous ultrasonic tests; calculate the environmental correlation of each ultrasonic test by comparing the relative temperature-humidity ratio and relative temperature difference of each ultrasonic test and all previous ultrasonic tests with the cumulative abnormality.

[0072] Furthermore, due to the temporal variation of freeze-thaw cycles, the reason why freeze-thaw cycle damage leads to internal cracking of concrete pavements is that when the ambient temperature is low and the humidity is high, there is more moisture inside the concrete pavement. When this moisture freezes, the volume of the frozen water expands, generating expansion stress. When this expansion stress exceeds the bearing capacity of the concrete material, the concrete cracks. Conversely, when the ambient temperature rises, the frozen water inside the concrete gradually thaws, and the expansion stress in the internal cracks of the concrete pavement disappears. As time progresses and the number of freeze-thaw cycles increases, the internal damage of the concrete continues to accumulate and expand. Early micro-cracks gradually enlarge and increase in subsequent freeze-thaw cycles, leading to a gradual increase in the degree of abnormality in ultrasonic signals. This cumulative effect causes the abnormality of ultrasonic signals to show an increasing trend, reflecting the continuous deterioration of the internal damage of the concrete.

[0073] Based on the above analysis, by analyzing the cumulative signal anomaly and its changing trend with environmental factors, the environmental correlation is calculated. The flowchart of the method for obtaining the environmental correlation for each ultrasound examination provided in this application embodiment is as follows: Figure 5 As shown, it specifically includes:

[0074] The sum of the signal abnormalities of each ultrasound examination and all previous ultrasound examinations is taken as the cumulative abnormality of each ultrasound examination.

[0075] It should be noted that, for ease of understanding, we assume 5 ultrasound examinations are performed, and the signal abnormality of each ultrasound examination is as follows: , , , , The cumulative abnormality in the first ultrasound examination was The cumulative abnormality in the second ultrasound examination was The cumulative abnormality in the third ultrasound examination was The cumulative abnormality in the 4th ultrasound examination was The cumulative abnormality of the 5th ultrasound examination was .

[0076] Calculate the average humidity at all times within the specified interval before each ultrasound examination, and record it as the average humidity.

[0077] Obtain the temperature troughs at all times within the specified interval, and record the average value of all troughs as the average low temperature.

[0078] In this embodiment, the AMPD (Automatic multiscale-based peak detection) algorithm is used to obtain the troughs. The AMPD algorithm is a well-known technology and will not be described in detail here. As other implementation methods, implementers may use other methods of existing technology, such as peak-trough second-order difference identification algorithms, etc. This embodiment does not impose any special restrictions on this.

[0079] The ratio between the average humidity and the average low temperature is used as the relative temperature-humidity ratio for each ultrasonic test.

[0080] The difference in detection temperature between each ultrasonic test and the previous ultrasonic test is denoted as the relative temperature difference of each ultrasonic test.

[0081] In this embodiment, the difference in detection temperature between each ultrasonic test and the previous ultrasonic test is denoted as the relative temperature difference of each ultrasonic test.

[0082] The correlation between the relative temperature difference of each ultrasound examination and all previous ultrasound examinations and the cumulative abnormality is calculated and denoted as the first correlation degree.

[0083] The correlation between the relative temperature and humidity ratio of each ultrasound examination and all previous ultrasound examinations and the cumulative abnormality is calculated and denoted as the second correlation degree.

[0084] Calculate the product of the first correlation and the second correlation as the environmental correlation for each ultrasound examination;

[0085] In this embodiment, the correlation is measured by calculating the Pearson correlation coefficient between the relative temperature difference and the cumulative anomaly of each ultrasonic test and all previous ultrasonic tests, and the Pearson correlation coefficient between the relative temperature-humidity ratio and the cumulative anomaly of each ultrasonic test and all previous ultrasonic tests. The absolute values ​​of the two Pearson correlation coefficients are used as the first correlation and the second correlation, respectively. The calculation of the Pearson correlation coefficient is a well-known technique and will not be described in detail here. As other implementation methods, implementers can use other methods of the prior art, such as Spearman correlation coefficient, cosine similarity, etc. This embodiment does not impose any special restrictions on this.

[0086] It should be noted that when freeze-thaw cycle damage occurs in concrete pavement, the different states of frozen water during the heating and cooling phases affect the propagation speed of sound waves within the concrete. This leads to a significant change in the degree of ultrasonic signal anomaly with temperature variations, resulting in a higher first correlation. Secondly, when humidity is high and temperature is low, the expansion stress within the concrete is greater, leading to a greater degree of abnormal change in the ultrasonic signal, resulting in a higher second correlation. Therefore, a higher first correlation indicates that temperature changes have a significant impact on the abnormality of ultrasonic signals within the concrete pavement, meaning that temperature fluctuations may be a major cause of changes in internal damage, making freeze-thaw cycle damage more likely. A higher second correlation indicates that the abnormal changes in ultrasonic signals within the concrete pavement are closely related to environmental factors, and environmental changes are more likely to trigger or exacerbate existing damage. For example, when humidity is high and temperature is low, more water inside the pavement will freeze, increasing the expansion stress within the concrete pavement and making it more prone to damage. A higher environmental correlation indicates a higher correlation between the fluctuation of ultrasonic signals within the concrete pavement and environmental changes, reflecting a greater likelihood of freeze-thaw cycle damage within the concrete pavement.

[0087] Thus, the environmental correlation of each ultrasound examination is obtained.

[0088] Step 4: Analyze the dispersion and trend of the cumulative abnormality of each ultrasonic test and all previous ultrasonic tests, combine the environmental correlation to determine the cumulative damage degree of each ultrasonic test, and combine the order of each ultrasonic test to obtain the evaluation coefficient of each ultrasonic test to evaluate the damage to the concrete pavement.

[0089] Furthermore, the flowchart of the method for obtaining the evaluation coefficient for each ultrasound examination provided in this application embodiment is as follows: Figure 6 As shown.

[0090] First, based on the aforementioned environmental relevance and the changing trend and fluctuations of the cumulative abnormality, the cumulative damage degree for each ultrasound examination is calculated, specifically as follows:

[0091] Calculate the dispersion of the cumulative abnormality for each ultrasound examination and all previous ultrasound examinations;

[0092] In this embodiment, the degree of dispersion is measured by calculating the variance of the cumulative anomaly of each ultrasound detection and all previous ultrasound detections. As an alternative implementation, the implementer may use other methods of the prior art, such as standard deviation, etc., and this embodiment does not impose any special restrictions on this.

[0093] It should be noted that the greater the degree of dispersion, the more unstable the changes in internal damage of the concrete are, and the more likely it is to continuously deteriorate.

[0094] The cumulative abnormality from each ultrasound examination and all previous ultrasound examinations is used to form an abnormality sequence; the first-order difference sequence of the abnormality sequence is calculated, and the proportion of negative elements in the first-order difference sequence is counted.

[0095] It should be noted that the calculation process of the first-order difference sequence is a well-known technique and will not be described in detail here.

[0096] Calculate the product of the degree of dispersion and the degree of environmental correlation, and use the ratio of the product to the proportion as the cumulative damage degree for each ultrasound examination;

[0097] It should be noted that, in order to avoid the denominator being 0 when calculating the ratio, a preset value greater than 0 is added to the denominator. In this embodiment, the preset value greater than 0 is 1. In other implementation methods, the implementer can set it according to the actual situation.

[0098] It should be noted that when concrete pavement suffers freeze-thaw cycle damage, the damage within the concrete increases with time and accumulation, leading to greater abnormal changes in the ultrasonic signals. Specifically, the abnormal sequence exhibits an increasing trend; the smaller the percentage of abnormal signals, the greater the dispersion, and consequently, the greater the cumulative damage. Therefore, a higher cumulative damage indicates a greater likelihood of freeze-thaw cycle damage to the concrete pavement.

[0099] Furthermore, based on the cumulative damage level and the number of each ultrasound examination and all previous ultrasound examinations, an evaluation coefficient is calculated, specifically as follows:

[0100] The number of each ultrasound examination and all previous ultrasound examinations was recorded.

[0101] The ratio of the cumulative damage to the number of times is used as the evaluation coefficient for each ultrasound examination.

[0102] It should be noted that since the effects of freeze-thaw damage on concrete accumulate over time, the degree of signal abnormality in concrete pavement under a single ultrasonic test is assessed by calculating the evaluation coefficient, in order to reflect the possibility of freeze-thaw cycle damage in concrete pavement.

[0103] Furthermore, based on the aforementioned evaluation coefficients, the damage inside the concrete pavement is assessed, specifically as follows:

[0104] Obtain the segmentation threshold for the evaluation coefficients of each ultrasound examination and all previous ultrasound examinations.

[0105] In this embodiment, the Otsu threshold segmentation algorithm is used to obtain the segmentation threshold. The Otsu threshold segmentation algorithm is a well-known technology and will not be described in detail here. As other implementation methods, implementers can use other methods of the prior art, such as cross-validation, etc. This embodiment does not impose any special restrictions on this.

[0106] If the evaluation coefficient of multiple consecutive ultrasonic tests is greater than the segmentation threshold, then there is freeze-thaw cycle damage inside the concrete pavement; otherwise, there is no freeze-thaw cycle damage inside the concrete pavement.

[0107] In this embodiment, if the evaluation coefficient of five consecutive ultrasonic tests is greater than the segmentation threshold, then freeze-thaw cycle damage exists inside the concrete pavement. As for other implementation methods, the implementer can set the appropriate value according to the actual situation.

[0108] The schematic diagram illustrating the changes in the evaluation coefficients for all ultrasound examinations provided in this application embodiment is as follows: Figure 7 As shown, by Figure 7 It can be seen that starting from the 9th ultrasonic test, the evaluation coefficient was continuously greater than the segmentation threshold of 0.395, indicating that there was freeze-thaw cycle damage inside the concrete pavement.

[0109] It should be noted that the evaluation coefficient can reflect the temporal changes of anomalies inside the concrete pavement and their correlation with environmental factors. At the same time, as the freeze-thaw cycle becomes more severe, the correlation between the abnormal changes of ultrasonic signals inside the concrete pavement and environmental factors will become stronger, thus increasing the evaluation coefficient. This means that freeze-thaw cycle damage is more likely to occur inside the concrete pavement.

[0110] Based on the same inventive concept as the above method, this application embodiment also provides a concrete pavement damage detection system, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of any one of the concrete pavement damage detection methods described above.

[0111] It should be understood that, although Figure 1 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order in which these steps are executed, and they can be performed in other orders. Figure 1 At least some of the steps in the process may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least some of the sub-steps or stages of other steps.

[0112] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0113] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application. Therefore, any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application, without departing from the content of the technical solution of this application, shall fall within the protection scope of the technical solution of this application.

Claims

1. A method for detecting damage to concrete pavement, characterized in that, The method includes the following steps: The ultrasonic signals of the concrete pavement during each ultrasonic test are obtained; the time period between the time before each ultrasonic test and the time after the previous ultrasonic test is recorded as the interval period before each ultrasonic test; the temperature and humidity at each moment within the interval period are obtained; and the average temperature within the corresponding time period of the ultrasonic signal of each ultrasonic test is recorded as the test temperature. Curve fitting is performed on all signal amplitudes in the ultrasonic signal. The overlap of the integral area of ​​the fitted curve between each ultrasonic test and the previous ultrasonic test is analyzed, and the signal anomaly degree of each ultrasonic test is calculated. The relative temperature-humidity ratio is calculated based on the average level of all humidity levels and the average level of all temperature troughs within the specified interval; the relative temperature difference is calculated based on the difference in detection temperature between two adjacent ultrasonic tests; and the cumulative abnormality of each ultrasonic test is obtained based on the signal abnormality of each ultrasonic test and all previous ultrasonic tests. The environmental correlation of each ultrasound test is calculated by comparing the relative temperature-humidity ratio and relative temperature difference of each ultrasound test and all previous ultrasound tests with the cumulative abnormality. The dispersion and trend of the cumulative anomalies of each ultrasonic test and all previous ultrasonic tests are analyzed. Combined with environmental correlation, the cumulative damage of each ultrasonic test is determined. Combined with the order of each ultrasonic test, the evaluation coefficient of each ultrasonic test is obtained to evaluate the damage to the concrete pavement. The calculation of the signal abnormality for each ultrasound detection includes: Calculate the area under the integral of the fitted curve corresponding to the ultrasonic signal for each ultrasonic test; Calculate the area of ​​the overlapping region under the fitted curve between each ultrasound examination and the previous ultrasound examination, and record it as the overlapping area. Calculate the sum of the integrated areas of each ultrasound detection and the previous ultrasound detection, and use the difference between the sum and a preset multiple of the overlapping area as the signal anomaly degree of each ultrasound detection.

2. The method for detecting damage to concrete pavement as described in claim 1, characterized in that, The calculation of the relative temperature-humidity ratio includes: Calculate the average humidity at all times within the specified interval before each ultrasound examination, and record it as the average humidity. Obtain the temperature troughs at all times within the specified interval, and record the average value of all troughs as the average low temperature. The ratio between the average humidity and the average low temperature is used as the relative temperature-humidity ratio for each ultrasonic test.

3. The method for detecting damage to concrete pavement as described in claim 1, characterized in that, The relative temperature difference is the difference between the detection temperature of each ultrasonic test and the previous ultrasonic test.

4. The method for detecting damage to concrete pavement as described in claim 1, characterized in that, The cumulative anomaly is the sum of the signal anomalies of each ultrasound examination and all previous ultrasound examinations.

5. The method for detecting damage to concrete pavement as described in claim 1, characterized in that, The calculation of the environmental relevance of each ultrasound examination includes: The correlation between the relative temperature difference of each ultrasound examination and all previous ultrasound examinations and the cumulative abnormality is calculated and denoted as the first correlation degree. The correlation between the relative temperature and humidity ratio of each ultrasound examination and all previous ultrasound examinations and the cumulative abnormality is calculated and denoted as the second correlation degree. The environmental relevance is the product of the first relevance and the second relevance.

6. The method for detecting damage to concrete pavement as described in claim 1, characterized in that, Determining the cumulative damage degree for each ultrasound examination includes: Calculate the dispersion of the cumulative abnormality for each ultrasound examination and all previous ultrasound examinations; The cumulative abnormality of each ultrasound examination and all previous ultrasound examinations is used to form an abnormality sequence. The first-order difference sequence of the abnormality sequence is calculated, and the proportion of negative elements in the first-order difference sequence is counted. Calculate the product of the degree of dispersion and the degree of environmental correlation; use the ratio of the product to the percentage as the cumulative damage degree for each ultrasound examination.

7. The method for detecting damage to concrete pavement as described in claim 1, characterized in that, The process of obtaining the evaluation coefficient for each ultrasound examination includes: counting the number of each ultrasound examination and all previous ultrasound examinations; and using the ratio of the cumulative damage to the number of examinations as the evaluation coefficient for each ultrasound examination.

8. The method for detecting damage to concrete pavement as described in claim 1, characterized in that, The assessment of damage to the concrete pavement includes: obtaining a segmentation threshold for the assessment coefficient of each ultrasonic test and all previous ultrasonic tests; if the assessment coefficient of multiple consecutive ultrasonic tests is greater than the segmentation threshold, then freeze-thaw cycle damage exists inside the concrete pavement, otherwise, freeze-thaw cycle damage does not exist inside the concrete pavement.

9. A concrete pavement damage detection system, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the concrete pavement damage detection method as described in any one of claims 1-8.

Images