A device and method for nondestructive combined detection of permeability and compaction degree of asphalt pavement

Abstract

The present application relates to the technical field of pavement engineering detection, and in particular to a kind of asphalt pavement permeability and compaction degree nondestructive combined detection device and method, solve the technical problem of low detection precision of prior art.The device comprises: data acquisition unit, for obtaining the detection data of target detection point;Detection data includes the ultrasonic data of target detection point before water spraying, and the ground penetrating radar data, infrared thermal imaging data and ultrasonic data of target detection point after water spraying;Permeability analysis unit, for carrying out permeability inversion analysis based on the infrared thermal imaging data after water spraying and the longitudinal wave propagation data in ultrasonic data before and after water spraying, to obtain the permeability coefficient of target detection point;Compaction degree analysis unit, for carrying out compaction degree inversion based on the ground penetrating radar data after water spraying and the ultrasonic data after water spraying, combined with the permeability coefficient of target detection point, to obtain the compaction degree of target detection point.

Description

Technical Field

[0001] This invention relates to the field of road engineering testing technology, specifically to a non-destructive testing device and method for asphalt pavement permeability and compaction. Background Technology

[0002] Asphalt pavement is a widely used type of road surface in road engineering, and its construction quality and performance directly affect the traffic safety and service life of roads. Permeability and compaction are two core indicators for evaluating the quality of asphalt pavement. Permeability reflects the pavement's ability to resist water penetration, directly related to the pavement's water stability and durability; compaction reflects the density of the pavement material, affecting the pavement's load-bearing capacity and deformation resistance. Therefore, accurate testing of these two indicators is of great significance for the quality control of road engineering projects.

[0003] In current engineering testing practices, permeability coefficients are typically measured using permeability meters, and compaction is measured using core drilling or nuclear density meters. Although non-destructive testing technologies such as ultrasonic testing, ground-penetrating radar, and infrared thermal imaging have been gradually applied to pavement inspection, most current testing methods target a single indicator, or, while integrating multiple sensors, fail to address the deep coupling interference between data from different physical fields. This makes it difficult to accurately obtain pavement permeability and compaction data simultaneously without damaging the pavement, especially when the pavement's moisture content is unknown or changing, often resulting in testing accuracy that falls short of high-standard engineering requirements. Summary of the Invention

[0004] To address the technical problem of low detection accuracy in existing technologies, the present invention aims to provide a non-destructive combined detection device and method for asphalt pavement permeability and compaction degree, the specific technical solution of which is as follows: This application provides a non-destructive testing device for asphalt pavement permeability and compaction, comprising: The data acquisition unit is used to acquire detection data of the target detection point; the detection data includes ultrasonic data of the target detection point before water spraying, and ground-penetrating radar data, infrared thermal imaging data and ultrasonic data of the target detection point after water spraying; the ultrasonic data includes longitudinal wave propagation data and transverse wave propagation data; The permeability analysis unit is used to perform permeability inversion analysis based on the longitudinal wave propagation data in the infrared thermal imaging data after water spraying and the ultrasonic data before and after water spraying, so as to obtain the permeability coefficient of the target detection point. The compaction analysis unit is used to perform compaction inversion based on ground-penetrating radar data and ultrasonic data after water spraying, combined with the permeability coefficient of the target detection point, to obtain the compaction degree of the target detection point.

[0005] This application provides a non-destructive testing method for the permeability and compaction of asphalt pavement, including: Acquire detection data of the target detection point; the detection data includes ultrasonic data of the target detection point before water spraying, and ground-penetrating radar data, infrared thermal imaging data and ultrasonic data of the target detection point after water spraying; the ultrasonic data includes longitudinal wave propagation data and transverse wave propagation data; Based on the longitudinal wave propagation data in the infrared thermal imaging data after water spraying and the ultrasonic data before and after water spraying, the permeability inversion analysis is performed to obtain the permeability coefficient of the target detection point. Based on ground-penetrating radar data and ultrasonic data after water spraying, the compaction degree of the target detection point is obtained by combining the permeability coefficient of the target detection point.

[0006] The present invention has the following beneficial effects: In view of the technical problem of low detection accuracy in existing technologies, this application provides a non-destructive testing device and method for asphalt pavement permeability and compaction. The data acquisition unit comprehensively acquires multi-dimensional detection data before and after water spraying, including ultrasonic data, ground-penetrating radar data, and infrared thermal imaging data, providing comprehensive and complementary data support for index inversion. The permeability analysis unit utilizes the synergistic effect of infrared thermal imaging data and ultrasonic longitudinal wave data to achieve accurate permeability inversion, avoiding the problem of single infrared detection failing to distinguish between total porosity and connected porosity. The compaction analysis unit uses ground-penetrating radar data and ultrasonic data acquired synchronously after water spraying, combined with permeability coefficient correction to eliminate the influence of pore morphology, effectively eliminating moisture interference and timing errors, and achieving accurate compaction inversion. The above technical solution achieves simultaneous non-destructive testing of permeability and compaction, solving the problems of low efficiency and insufficient accuracy of single-index detection in existing technologies, and improving the scientificity and practicality of pavement quality testing. Attached Figure Description

[0007] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0008] Figure 1 This is a schematic diagram of a non-destructive testing device for asphalt pavement permeability and compaction provided in an embodiment of the present invention. Figure 2 This is a schematic flowchart of a non-destructive testing method for the permeability and compaction of asphalt pavement provided in one embodiment of the present invention. Detailed Implementation

[0009] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a non-destructive testing device and method for asphalt pavement permeability and compaction based on the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0010] 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 invention pertains.

[0011] In all division and logarithmic operations covered in this application, a smoothing mechanism is employed to prevent computer program crashes or invalid values ​​from being generated due to a zero denominator or a zero input. Specifically, a positive correction factor is superimposed on the denominator term of the division operation or the argument term of the logarithmic function. For example, the value is This ensures the robustness and feasibility of the algorithm under extreme conditions.

[0012] The normalization function mentioned in this application Unless otherwise specified, all values ​​are normalized using maximum and minimum values. The maximum and minimum values ​​are preset empirical extreme values ​​derived from a large amount of historical experimental data. If the calculated result exceeds the [0,1] interval, it is restricted to the [0,1] range by a truncation function (i.e., if the result is less than 0, it is taken as 0, and if it is greater than 1, it is taken as 1) to eliminate the influence of outliers on the evaluation index.

[0013] The following description, in conjunction with the accompanying drawings, details the specific scheme of the non-destructive testing device and method for asphalt pavement permeability and compaction provided by the present invention.

[0014] Please see Figure 1 The diagram shows a structural schematic of a non-destructive testing device for asphalt pavement permeability and compaction provided in an embodiment of the present invention. The non-destructive testing device 10 for asphalt pavement permeability and compaction includes: a data acquisition unit 11, a permeability analysis unit 12, and a compaction analysis unit 13.

[0015] The data acquisition unit 11 is used to acquire the detection data of the target detection point.

[0016] The detection data includes ultrasonic data of the target detection point before water spraying, and ground-penetrating radar data, infrared thermal imaging data, and ultrasonic data of the target detection point after water spraying. The ultrasonic data includes longitudinal wave propagation data and transverse wave propagation data. The target detection point refers to the specific location of the area to be detected, which can be located based on road markings or a positioning system. This application allows for the uniform distribution or targeted selection of target detection points within the road section according to detection needs.

[0017] For example, longitudinal wave propagation data in ultrasonic data may include parameters such as longitudinal wave propagation time, longitudinal wave propagation velocity, and received amplitude. Longitudinal waves can propagate in both solids and liquids, and their propagation characteristics are affected by the water-filled state of the pores. Transverse wave propagation data may include parameters such as transverse wave propagation time, transverse wave propagation velocity, and received amplitude; however, transverse waves cannot pass through liquids and can only reflect the characteristics of the solid skeleton.

[0018] Ground-penetrating radar (GPR) data can include electromagnetic wave two-way propagation time and reflected wave amplitude, used to characterize the electromagnetic response properties of road surface materials. Infrared thermal imaging data includes the surface temperature distribution of the road surface at different sampling times, used to reflect the temperature change patterns during moisture infiltration.

[0019] The data acquisition unit 11 can work with a vehicle-mounted platform to achieve mobile detection. The lifting structure ensures stable contact with the road surface during the detection process, adapts to different road surface smoothness, and ensures the stability and accuracy of data acquisition.

[0020] In some embodiments, the data acquisition unit 11 includes: a quantitative water spraying module, an ultrasonic sensing module, a ground penetrating radar module, and an infrared sensing module.

[0021] The metered water spraying module is used to spray water quantitatively onto the target detection points. This module can simulate moderate rain infiltration conditions, filling the road surface pores with water, creating the physical conditions for permeability testing, and providing a known moisture environment for compaction testing.

[0022] For example, the quantitative water spraying module can employ intelligent water supply control technology, precisely controlling the water spray volume through flow sensors and pressure regulating valves. For instance, the spray volume can be set to 0.5 L / m², ensuring uniform coverage of the target detection point and preventing excessive localized water accumulation from affecting the detection results. The spraying process duration can be controlled to approximately 30 seconds, ensuring that the water initially wets the road surface without generating excessive runoff.

[0023] An ultrasonic sensing module is used to collect ultrasonic data before water spraying and after water spraying. This module can consist of multiple ultrasonic transducers, for example, a separate layout of 4 transmitters and 4 receivers, capable of simultaneously transmitting and receiving longitudinal and transverse waves.

[0024] For example, the transducer can generate longitudinal waves using the thickness vibration mode of a piezoelectric ceramic sheet, while simultaneously exciting transverse waves through tangential polarization by attaching a thin shear piezoelectric element to the surface of the ceramic sheet. This allows a single transducer to generate two wave modes simultaneously, and wave mode identification and separation are achieved through signal processing circuitry. To ensure acoustic coupling, a silicone coupling pad is placed between the transducer and the road surface. This pad, embedded with rigid fibers, ensures both adhesion to the road surface and effective transmission of shear stress. Furthermore, it can be completely peeled off after use without leaving any residue, meeting the requirements for non-destructive testing. The transducer array can automatically rise and fall, adjusting its height to maintain close contact with the ground and ensuring the stability of data acquisition.

[0025] The ground-penetrating radar module is used to collect ground-penetrating radar data after water spraying. The antenna unit of this ground-penetrating radar module can be deployed at the center of the sensor array. It adopts a dual-polarized antenna design, which can simultaneously transmit and receive horizontally polarized waves and vertically polarized waves, thereby more accurately identifying the spatial orientation characteristics of the internal pores of the road surface.

[0026] For example, a metal shielding ring can be installed around the antenna unit to suppress lateral clutter interference and ensure the accuracy of electromagnetic wave propagation data. The ground-penetrating radar module emits electromagnetic waves and collects data on the two-way propagation time and reflected wave amplitude within the road surface, providing a basis for calculating the dielectric constant.

[0027] The infrared sensing module is used to collect infrared thermal imaging data after water spraying.

[0028] For example, the infrared sensing module can consist of multiple infrared detectors evenly distributed circumferentially around the ground-penetrating radar antenna unit. The spectral response range of the infrared detectors can be selected in the mid-to-long-wave infrared band (3-5 μm), and an adjustable-focus lens system is configured at the front end. By adjusting the focal length, multi-angle observation can be achieved to obtain high-definition three-dimensional temperature field distribution of the road surface. In this application, the infrared sensing module can be activated after water spraying ends, continuously collecting temperature distribution data over 600 seconds at 10-second intervals to form a temperature decay time-series curve, providing data support for permeability analysis.

[0029] The permeability analysis unit 12 is used to perform permeability inversion analysis based on the longitudinal wave propagation data in the infrared thermal imaging data after water spraying and the ultrasonic data before and after water spraying, so as to obtain the permeability coefficient of the target detection point.

[0030] The permeability coefficient is used to characterize the permeability of the road surface material at the target detection point. It can reflect the ease with which water passes through the interconnected pores of the road surface. The larger the permeability coefficient, the stronger the permeability.

[0031] It should be noted that infrared thermal imaging data can reflect the temperature changes on the road surface caused by water infiltration and evaporation, while ultrasonic longitudinal wave propagation data can characterize the water filling process of connected pores. Therefore, this application can eliminate the interference of total porosity on permeability inversion by combining infrared thermal imaging data after water spraying and longitudinal wave propagation data in ultrasonic data before and after water spraying.

[0032] The compaction analysis unit 13 is used to perform compaction inversion based on ground-penetrating radar data and ultrasonic data after water spraying, combined with the permeability coefficient of the target detection point, to obtain the compaction of the target detection point.

[0033] Compaction degree, also known as compaction degree, refers to the ratio of the dry density of road material after compaction to the standard maximum dry density. It is usually expressed as a percentage and can reflect the compaction effect of road material. The higher the compaction degree, the better the road compaction effect.

[0034] It should be noted that the ultrasonic data (including transverse and longitudinal wave propagation data) were collected synchronously after permeability measurement (when the road surface was in a water-containing state after water spraying). Transverse wave propagation data is unaffected by moisture and accurately reflects the compaction degree of the solid skeleton, while longitudinal wave propagation data is affected by moisture and can help determine moisture saturation. Ground-penetrating radar data after water spraying is also affected by moisture and requires correction. This application can combine permeability coefficients to correct the influence of pore morphology on compaction calculations, ensuring data temporal consistency and matching.

[0035] Based on the above technical solutions, this application can comprehensively acquire multi-dimensional detection data before and after water spraying through the data acquisition unit 11, covering ultrasonic data, ground-penetrating radar data, and infrared thermal imaging data, providing comprehensive and complementary data support for index inversion. The permeability analysis unit 12 utilizes the synergistic effect of infrared thermal imaging data and ultrasonic longitudinal wave data to achieve accurate permeability inversion, avoiding the problem that single infrared detection is difficult to distinguish between total porosity and connected porosity. The compaction degree analysis unit 13 uses ground-penetrating radar data and ultrasonic data collected synchronously after water spraying, combined with the permeability coefficient to correct the influence of pore morphology, effectively eliminating moisture interference and time sequence errors, and achieving accurate compaction degree inversion. The above technical solutions realize simultaneous non-destructive testing of permeability and compaction degree, solving the problems of low efficiency and insufficient accuracy of single index detection in existing technologies, and improving the scientificity and practicality of pavement quality testing.

[0036] As one possible embodiment of this application, the permeability analysis unit 12 includes: an infrared data processing module, a longitudinal wave dynamics analysis module, and a permeability coefficient calculation module.

[0037] The infrared data processing module is used to determine the surface temperature decay curve of the road surface based on the infrared thermal imaging data after water spraying, and to perform piecewise linear fitting on the temperature decay curve to determine the slope of the temperature decay curve in the target segment.

[0038] The segmented slope is used to characterize the rate at which moisture infiltration into interconnected pores affects the surface temperature of the road surface. The road surface temperature decay curve refers to the curve showing the change in road surface temperature over time after water spraying.

[0039] The surface temperature decay curve of this road surface is influenced by two effects: the cooling effect of water evaporation and the cooling effect of surface water loss after water seeps in through interconnected pores. These two effects act on different stages. In the rapid change stage, the temperature rises rapidly, mainly driven by infiltration cooling, typically within 0-100 seconds after water spraying. In the slow change stage, the temperature change tends to stabilize, mainly driven by evaporative cooling, typically after 100 seconds after water spraying. The aforementioned 100 seconds is an empirical value based on standard test conditions (no wind, constant illumination). In practical applications, the segment points can be dynamically adjusted according to environmental parameters, which will not be elaborated further.

[0040] The target segment in this application refers to the rapid change stage dominated by infiltration cooling in the surface temperature decay curve of the road surface. By segmented linear fitting, the influence of infiltration cooling can be separated from the superposition effect. The larger the absolute value of the segment slope, the faster the rate of water infiltration into the connected pores and the higher the connected porosity.

[0041] The longitudinal wave dynamics analysis module is used to determine the penetration time constant based on the longitudinal wave propagation data in the ultrasonic data before and after water spraying.

[0042] The infiltration time constant is used to characterize the infiltration time of water in connected pores, indirectly reflecting how quickly water fills these pores. Before water spraying, the pores of the road surface are filled with air, resulting in a slow propagation velocity in the acquired longitudinal wave propagation data. After water spraying, water gradually fills the connected pores, replacing the air, and the propagation velocity in the acquired longitudinal wave propagation data increases significantly. The change in longitudinal wave propagation velocity is directly related to the water filling process of the connected pores. Therefore, by analyzing the variation law of longitudinal wave propagation data, this application can quantify the dynamic characteristics of water infiltration, thereby obtaining the infiltration time constant.

[0043] In one possible implementation, the longitudinal wave dynamics analysis module is specifically used to: calculate the longitudinal wave velocity increment corresponding to each sampling moment based on the longitudinal wave propagation data in the ultrasonic data before and after water spraying, and perform infiltration dynamics simulation based on the longitudinal wave velocity increment corresponding to each sampling moment to obtain the infiltration time constant.

[0044] The longitudinal wave velocity increment refers to the difference between the longitudinal wave velocity at a certain sampling moment after water spraying and the longitudinal wave velocity before water spraying. Before water spraying, the pores in the pavement are mainly filled with air, resulting in a low longitudinal wave velocity. After water spraying, water gradually seeps into the interconnected pores, replacing air and occupying the pore space, causing the longitudinal wave velocity to gradually increase. The longitudinal wave velocity increment can directly reflect the water filling ratio of the interconnected pores.

[0045] For example, this application can achieve permeation kinetics simulation through a permeation kinetics model, which can be expressed by the following formula: in, Sampling time The corresponding longitudinal wave velocity increment, This represents the maximum value among the P-wave velocity increments at each sampling time, used to characterize the P-wave velocity increment when the road surface reaches saturation. This is the permeation time constant.

[0046] in the formula It is an exponential growth term. hour, =0, This corresponds to the initial state where the longitudinal wave velocity remains unchanged at the moment the water jet ends. Increase Gradually approaching 0, Gradually approaching This reflects the process by which the interconnected pores are gradually filled with water, and the increase in longitudinal wave velocity tends to stabilize. The size determines the growth rate. The smaller the value, the faster the growth rate, indicating a faster water permeation rate and stronger permeability of the interconnected pores.

[0047] This formula, by simulating the variation of P-wave velocity increment with time, can accurately invert the penetration time constant. The permeation time constant The permeation rate of water in interconnected pores was quantified, providing key kinetic parameters for calculating the permeability coefficient.

[0048] In some embodiments, this application can use the least squares method to perform simulations at multiple sampling times during the simulation process. The data is fitted to determine The optimal solution is obtained to ensure the consistency between the simulation results and the actual infiltration process.

[0049] The permeability coefficient calculation module is used to calculate the permeability coefficient of the target detection point based on the segmented slope and the permeation time constant.

[0050] Among them, the segmented slope reflects the magnitude of the interconnected porosity, and the infiltration time constant reflects the infiltration rate of water in the interconnected pores. Together, they determine the permeability of the road surface.

[0051] In one possible implementation, the permeability coefficient calculation module is specifically used to: normalize the segmented slope to obtain the connected porosity, and calculate the permeability coefficient based on the connected porosity and the permeation time constant.

[0052] The connectivity porosity is used to characterize the volume ratio of interconnected pores through which water molecules flow in the pavement material at the target detection point. The segmented slope is the absolute value of the slope of the target segment (the penetration-cooling-dominated stage) obtained by the infrared data processing module. This segmented slope is directly proportional to the connectivity porosity; that is, the larger the segmented slope, the higher the connectivity porosity. The normalized baseline value is the preset standard temperature drop rate under fully connected or fully closed conditions. For example, the standard temperature drop rate under fully connected conditions can be measured using laboratory-calibrated asphalt specimens with high connectivity porosity, and the standard temperature drop rate under fully closed conditions can be measured using asphalt specimens with 100% density. The normalized connectivity porosity value ranges from 0 to 1, where 0 represents fully closed and 1 represents fully connected, intuitively reflecting the proportion of interconnected pores.

[0053] In some embodiments, the normalization process may employ a linear normalization method, which means that the difference between the segmented slope and the fully closed standard slope can be divided by the difference between the fully connected standard slope and the fully closed standard slope to obtain the connected porosity.

[0054] For example, this application can calculate the permeability coefficient based on Darcy's law, that is, permeability is directly proportional to the cube of the interconnected porosity and inversely proportional to the permeation time constant.

[0055] For example, the permeability coefficient satisfies the following formula: in, Permeability coefficient, The calibration coefficients are obtained through experiments using standard specimens with different interconnected porosities and permeation time constants. They are used to correct deviations between the theoretical model and actual conditions. For interconnected porosity, This is the permeation time constant.

[0056] Based on the above technical solutions, the infrared data processing module in this application effectively separates the effects of infiltration cooling and evaporative cooling through piecewise fitting technology, accurately extracting characteristic parameters related to interconnected porosity. The longitudinal wave dynamics analysis module utilizes the sensitivity of longitudinal wave velocity to moisture to quantify the dynamic process of water infiltration, obtaining a permeation time constant that reflects the infiltration rate. The permeability coefficient calculation module, based on the synergistic effect of the two, achieves accurate inversion of the permeability coefficient. These technical solutions avoid the limitations of single detection methods, improve the accuracy and reliability of permeability detection, and provide crucial auxiliary parameters for subsequent compaction degree detection.

[0057] As one possible embodiment of this application, the compaction analysis unit 13 includes: a dielectric constant processing unit, a correction unit, and a compaction calculation unit.

[0058] The dielectric constant processing unit is used to determine the equivalent dielectric constant of the target detection point in the water-bearing state after water spraying based on the ground penetrating radar data after water spraying.

[0059] The equivalent dielectric constant in the hydrated state is used to characterize the dielectric polarization strength of the pavement material at the target detection point in the hydrated state. The equivalent dielectric constant in the hydrated state is affected by the dielectric constants of the solid, gas, and liquid phases in the pavement material, reflecting the overall electromagnetic response characteristics of the pavement material.

[0060] In one possible implementation, the dielectric constant processing unit is specifically used to: determine the two-way propagation time of electromagnetic waves based on the ground-penetrating radar data after water spraying, determine the propagation speed of electromagnetic waves in combination with the road surface thickness at the target detection point, and determine the equivalent dielectric constant of the water-containing state based on the propagation speed of electromagnetic waves.

[0061] The electromagnetic wave two-way propagation time refers to the total time it takes for an electromagnetic wave emitted from a ground-penetrating radar antenna, reflected from the road surface, and return to the antenna. This time can be extracted by processing the ground-penetrating radar data. The road surface thickness at the target detection point can be obtained from previous road construction records or measured on-site using non-destructive testing methods. For example, the road surface thickness can be set to 5cm-10cm, specifically determined based on the design thickness of the actual road section being tested. Thus, this application can determine the total propagation path of the electromagnetic wave based on the road surface thickness and the distance of the ground-penetrating radar from the ground, and then calculate the electromagnetic wave propagation speed by combining this with the electromagnetic wave two-way propagation time.

[0062] Subsequently, this application can calculate the equivalent dielectric constant in the water-saturated state based on the relationship between electromagnetic wave propagation speed and dielectric constant derived from Maxwell's equations, namely, that the electromagnetic wave propagation speed is inversely proportional to the square root of the dielectric constant. Since the aforementioned electromagnetic wave propagation speed is determined based on ground-penetrating radar data after water spraying, this equivalent dielectric constant in the water-saturated state reflects the overall electromagnetic response characteristics of the pavement material in the water-saturated state. This application requires further correction to obtain the equivalent dielectric constant in the dry state.

[0063] The correction unit is used to correct the equivalent dielectric constant based on the transverse wave propagation data and longitudinal wave propagation data in the ultrasonic data after water spraying, so as to obtain the equivalent dielectric constant in the dry state.

[0064] Among them, the dry-state equivalent dielectric constant is used to characterize the corrected dielectric polarization strength of the pavement material at the target detection point. That is to say, the dry-state equivalent dielectric constant is the equivalent dielectric constant that reflects only the solid skeleton and air pores after eliminating the influence of moisture, and it is the core basic parameter for calculating the compaction degree in this application.

[0065] Since the equivalent dielectric constant of the water-bearing state is greatly affected by moisture, directly using it for compaction calculation will lead to deviation. Therefore, this application needs to determine the porosity and moisture saturation by simultaneously collecting ultrasonic transverse and longitudinal wave data after water spraying, thereby separating the influence of moisture and achieving accurate correction of the dielectric constant. This ensures that the correction process is completely matched with the measurement timing of the dielectric constant of the water-bearing state, avoiding timing errors.

[0066] In one possible implementation, the correction unit is used to determine the pavement porosity based on the transverse wave propagation data in the ultrasonic data after water spraying.

[0067] Among them, pavement porosity is used to characterize the total volume ratio of all pores in the pavement material at the target detection point.

[0068] The pavement porosity is the total porosity, including connected pores and closed pores. The pavement porosity and shear wave propagation data satisfy the following physical relationship formula: in, To determine the propagation speed of the transverse wave in the ultrasonic data after water spraying, an ultrasonic array sensor consisting of multiple ultrasonic transducers can be used for multi-point excitation and multi-point reception measurement. To ensure the effectiveness of the transverse propagation path, the ultrasonic transducer excitation and reception points can adopt a combination of paths such as diagonal intersection and straight edge. After obtaining the ultrasonic travel time data corresponding to multiple paths, the propagation speed is calculated by combining the corresponding path lengths, and the average propagation speed of each path is taken as the final propagation speed. The propagation velocity in the transverse wave propagation data of the standard asphalt mixture solid skeleton calibrated in the laboratory. For pavement gap ratio, This is the power-law exponent of the pavement material; for asphalt mixtures, it is typically taken as 1.8-2.0.

[0069] The above formula utilizes the characteristic that shear waves propagate only within a solid framework and are unaffected by moisture. By inverting the shear wave velocity collected after water spraying, the pavement porosity is obtained, accurately reflecting the total volume ratio of all pores in the pavement material. Compared to traditional methods of directly measuring porosity, this method, based on ultrasonic data, achieves non-destructive testing, improving testing efficiency while ensuring the accuracy of porosity calculation and providing key parameters for dielectric constant correction.

[0070] The calibration unit is used to determine the moisture saturation of the target detection point based on the transverse wave propagation data and longitudinal wave propagation data in the ultrasonic data after water spraying.

[0071] Among them, moisture saturation is used to characterize the proportion of water filling the road surface pores at the target detection point.

[0072] Since longitudinal waves can propagate in both solids and liquids and their speed is greatly affected by moisture, while transverse waves only propagate in solids and their speed is not affected by moisture, this application can use the ratio of the propagation speed of longitudinal waves to the propagation speed of transverse waves, which are collected synchronously after water spraying, as the moisture saturation of the target detection point.

[0073] The correction unit is used to correct the equivalent dielectric constant of the water-containing state based on the pneumatics and moisture saturation of the road surface, so as to obtain the equivalent dielectric constant of the dry state.

[0074] For example, the equivalent dielectric constant in the dry state satisfies the following formula: in, The equivalent dielectric constant in the dry state is... The equivalent dielectric constant in the water-bearing state, The moisture interference correction term can be determined by the pavement porosity and moisture saturation.

[0075] For example, the moisture interference correction term satisfies the following formula: in, For moisture interference correction term, As calibration coefficients, they can be obtained through different saturation levels. and pavement gap ratio The corresponding moisture interference correction term data were experimentally analyzed and determined, typically between 0.8 and 1.2, reflecting the nonlinear characteristics of dielectric mixing. For pavement gap ratio, Water saturation The dielectric constant of water is approximately 81. is the dielectric constant of air (approximately 1).

[0076] This is the moisture interference correction term, which characterizes the incremental contribution of moisture to the mixed dielectric constant. (Approximately 80) is the difference in dielectric constant between water and air, reflecting the significant influence of moisture on dielectric properties. It reflects the volume percentage of water in the road surface. The larger the moisture content, the more significant its effect on the dielectric constant.

[0077] This application effectively eliminates the interference of moisture on the dielectric constant by subtracting the increase in dielectric constant caused by moisture, thus obtaining an equivalent dielectric constant in the dry state that truly reflects the characteristics of the solid skeleton and air pores. The porosity and moisture saturation used in the correction process are calculated based on ultrasonic data collected synchronously after water spraying, which is completely consistent with the measurement sequence of the dielectric constant in the hydrated state, avoiding timing errors, improving correction accuracy, and providing key basic parameters for the accurate calculation of subsequent compaction.

[0078] The compaction calculation unit is used to calculate the compaction of the target detection point based on the ultrasonic data after water spraying, the equivalent dielectric constant in the dry state, and the permeability coefficient of the target detection point.

[0079] The ultrasonic data after water spraying is used to analyze the morphological characteristics of road pores (such as anisotropy), while the permeability coefficient is used to reflect the distribution of interconnected pores. Combining the two can correct the influence of pore morphology on compaction calculation. In one possible implementation, the compaction calculation unit is used to determine the ultrasonic anisotropy index of the target detection point based on the ultrasonic data after water spraying.

[0080] Among them, the ultrasonic anisotropy index is used to characterize the degree of directional difference in the wave velocity of ultrasonic waves in the road surface material at the target detection point.

[0081] For example, this application can obtain the wave velocity at the target detection point along different directions based on the ultrasonic data collected after water spraying, calculate the wave velocity difference between each direction and the average wave velocity, then calculate the variance of all wave velocity difference values, and normalize the variance (the normalization benchmark value is the variance of the theoretical maximum wave velocity difference value, that is, the variance of the wave velocity difference value calculated under the most extreme anisotropic state that the road material may appear), to obtain the ultrasonic anisotropy index.

[0082] The smaller the ultrasonic anisotropy index, the more consistent the wave velocity in all directions, indicating that the material is isotropic and the pores are randomly distributed. The larger the ultrasonic anisotropy index, the more directional the pores or microcracks are, and the more obvious the anisotropic characteristics of the material.

[0083] The compaction calculation unit is used to determine the morphological factor based on the permeability coefficient and the ultrasonic anisotropy index.

[0084] Among them, the morphology factor is used to characterize the correction coefficient of road surface void morphology for compaction degree calculation.

[0085] For example, the morphological factor satisfies the following formula: in, For morphological factors, The anisotropy index of ultrasound. This is the normalized value of the permeability coefficient (the normalized benchmark value is the maximum allowable permeability coefficient in the asphalt pavement design specification). A larger ultrasonic anisotropy index indicates a more pronounced directional arrangement of pores. The larger the value, the stronger the permeability of the connected pores. The larger the product of the two, the greater the interference of pore morphology on the compaction degree calculation. The smaller the morphology factor, the greater the reduction in compaction degree.

[0086] The compaction degree calculation unit is used to determine the compaction degree based on the equivalent dielectric constant and morphology factor of the dry state.

[0087] For example, the degree of compaction satisfies the following formula: in, For compaction degree, The equivalent dielectric constant in the dry state is... The standard dielectric constant for a standard dense state (100% compaction) can be obtained by measuring standard dense asphalt specimens calibrated in the laboratory. For morphological factors.

[0088] It reflects the density of the solid skeleton of the road surface. The closer This indicates that the higher the density of the solid skeleton, the greater the basic compaction value. The correction factor is used to correct the basic compaction obtained from the dielectric constant ratio, thereby eliminating interference from pore morphology.

[0089] Based on the above technical solution, the dielectric constant processing unit in this application obtains the basic electromagnetic parameters under water-containing conditions, providing raw data for compaction degree analysis. The correction unit, through the synergistic effect of ultrasonic transverse and longitudinal wave data synchronously acquired after water spraying, effectively eliminates the interference of moisture on the dielectric constant and avoids timing errors, obtaining the equivalent dielectric constant of the dry state that truly reflects the characteristics of the solid skeleton. The compaction degree calculation unit, combined with pore morphology characteristics and permeability coefficient, achieves accurate inversion of compaction degree. The above technical solution effectively solves the problem of interference from moisture and pore morphology in compaction degree inversion in the prior art, improving the accuracy and reliability of compaction degree detection.

[0090] Please see Figure 2 The diagram illustrates a flowchart of a non-destructive testing method for the permeability and compaction of asphalt pavement according to an embodiment of the present invention. The method includes the following steps: Step 201: Obtain the detection data of the target detection point; the detection data includes the ultrasonic data of the target detection point before water spraying, and the ground penetrating radar data, infrared thermal imaging data and ultrasonic data of the target detection point after water spraying; the ultrasonic data includes longitudinal wave propagation data and transverse wave propagation data; Step 202: Perform a permeability inversion analysis based on the longitudinal wave propagation data in the infrared thermal imaging data after water spraying and the ultrasonic data before and after water spraying to obtain the permeability coefficient of the target detection point; Step 203: Based on the ground-penetrating radar data and ultrasonic data after water spraying, and combined with the permeability coefficient of the target detection point, the compaction degree is inverted to obtain the compaction degree of the target detection point.

[0091] It should be noted that the various embodiments of this application can be referenced or learned from each other. For example, the same or similar steps, method embodiments, system embodiments and device embodiments can be referenced from each other without limitation.

[0092] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0093] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

Claims

1. A non-destructive testing device for asphalt pavement permeability and compaction, characterized in that, include: A data acquisition unit is used to acquire detection data of the target detection point; the detection data includes ultrasonic data of the target detection point before water spraying, and ground-penetrating radar data, infrared thermal imaging data, and ultrasonic data of the target detection point after water spraying; the ultrasonic data includes longitudinal wave propagation data and transverse wave propagation data. The permeability analysis unit is used to perform permeability inversion analysis based on the longitudinal wave propagation data in the infrared thermal imaging data after water spraying and the ultrasonic data before and after water spraying, so as to obtain the permeability coefficient of the target detection point. The compaction analysis unit is used to perform compaction inversion based on ground-penetrating radar data and ultrasonic data after water spraying, combined with the permeability coefficient of the target detection point, to obtain the compaction of the target detection point. The permeability analysis unit includes: The infrared data processing module is used to determine the surface temperature decay curve of the road surface based on the infrared thermal imaging data after water spraying, and to perform piecewise linear fitting on the temperature decay curve to determine the segment slope of the temperature decay curve in the target segment; the segment slope is used to characterize the rate of influence of water seeping into the interconnected pores on the surface temperature of the road surface. The longitudinal wave dynamics analysis module is used to determine the infiltration time constant based on the longitudinal wave propagation data in the ultrasonic data before and after water spraying; the infiltration time constant is used to characterize the infiltration time of water in the interconnected pores. The permeability coefficient calculation module is used to calculate the permeability coefficient of the target detection point based on the segmented slope and the permeation time constant. The compaction degree analysis unit includes: The dielectric constant processing unit is used to determine the equivalent dielectric constant of the target detection point in the water-bearing state after water spraying based on the ground penetrating radar data after water spraying; the equivalent dielectric constant in the water-bearing state is used to characterize the dielectric polarization strength of the road surface material at the target detection point in the water-bearing state; An equivalent dielectric constant correction unit is used to correct the equivalent dielectric constant based on the transverse wave propagation data and longitudinal wave propagation data in the ultrasonic data after water spraying, so as to obtain the equivalent dielectric constant in the dry state; the equivalent dielectric constant in the dry state is used to characterize the corrected dielectric polarization strength of the road surface material at the target detection point. The compaction calculation unit is used to calculate the compaction of the target detection point based on the ultrasonic data after water spraying, the equivalent dielectric constant of the dry state, and the permeability coefficient of the target detection point.

2. The non-destructive testing device for asphalt pavement permeability and compaction degree according to claim 1, characterized in that, The data acquisition unit includes: A quantitative water spraying module is used to spray water quantitatively onto the target detection point; An ultrasonic sensing module is used to collect ultrasonic data before water spraying and ultrasonic data after water spraying. Ground penetrating radar module, used to collect ground penetrating radar data after water spraying; The infrared sensing module is used to collect infrared thermal imaging data after water spraying.

3. The non-destructive testing device for asphalt pavement permeability and compaction degree according to claim 1, characterized in that, The longitudinal wave dynamics analysis module is specifically used for: The longitudinal wave velocity increment at each sampling moment is calculated based on the longitudinal wave propagation data in the ultrasonic data before and after water spraying. The permeation time constant is obtained by performing a permeation dynamics simulation based on the longitudinal wave velocity increment corresponding to each sampling time.

4. The non-destructive testing device for asphalt pavement permeability and compaction degree according to claim 1, characterized in that, The permeability coefficient calculation module is specifically used for: The connected porosity is obtained by normalizing the segmented slope; the connected porosity is used to characterize the volume ratio of connected pores through which water molecules flow in the road surface material at the target detection point. The permeability coefficient is calculated based on the interconnected porosity and the permeation time constant.

5. The non-destructive testing device for asphalt pavement permeability and compaction degree according to claim 1, characterized in that, The dielectric constant processing unit is specifically used for: The electromagnetic wave two-way propagation time is determined based on the ground-penetrating radar data after water spraying, and the electromagnetic wave propagation speed is determined in combination with the road surface thickness at the target detection point. The equivalent dielectric constant of the water-bearing state is determined based on the propagation speed of the electromagnetic wave.

6. The non-destructive testing device for asphalt pavement permeability and compaction degree according to claim 1, characterized in that, The correction unit is specifically used for: The pavement porosity is determined based on the transverse wave propagation data in the ultrasonic data after water spraying; the pavement porosity is used to characterize the total volume ratio of all pores in the pavement material at the target detection point. The moisture saturation of the target detection point is determined based on the transverse wave propagation data and longitudinal wave propagation data in the ultrasonic data after water spraying; the moisture saturation is used to characterize the proportion of water filling the road surface pores at the target detection point. The equivalent dielectric constant of the water-containing state is corrected based on the pneumatic ratio of the road surface and the moisture saturation to obtain the equivalent dielectric constant of the dry state.

7. The non-destructive testing device for asphalt pavement permeability and compaction degree according to claim 1, characterized in that, The compaction degree calculation unit is specifically used for: The ultrasonic anisotropy index of the target detection point is determined based on the ultrasonic data after water spraying; the ultrasonic anisotropy index is used to characterize the degree of directional difference in the wave velocity of ultrasonic waves in the road surface material at the target detection point. The morphology factor is determined based on the permeability coefficient and the ultrasonic anisotropy index; the morphology factor is used to characterize the correction factor for the compaction degree calculation based on the pavement morphology. The compaction degree is determined based on the equivalent dielectric constant of the dry state and the morphology factor.

8. A non-destructive testing method for the permeability and compaction degree of asphalt pavement, characterized in that, include: Acquire detection data of the target detection point; the detection data includes ultrasonic data of the target detection point before water spraying, and ground-penetrating radar data, infrared thermal imaging data, and ultrasonic data of the target detection point after water spraying; the ultrasonic data includes longitudinal wave propagation data and transverse wave propagation data; Based on the longitudinal wave propagation data in the infrared thermal imaging data after water spraying and the ultrasonic data before and after water spraying, a permeability inversion analysis is performed to obtain the permeability coefficient of the target detection point. Based on the ground-penetrating radar data and ultrasonic data after water spraying, and combined with the permeability coefficient of the target detection point, the compaction degree of the target detection point is obtained by inverting the compaction degree. The permeability coefficient of the target detection point is obtained by: Based on the infrared thermal imaging data after water spraying, a surface temperature decay curve is determined, and the temperature decay curve is subjected to piecewise linear fitting to determine the slope of the temperature decay curve in the target segment; the piecewise slope is used to characterize the rate of influence of water seepage into the interconnected pores on the surface temperature of the road. The infiltration time constant is determined based on the longitudinal wave propagation data in the ultrasonic data before and after water spraying; the infiltration time constant is used to characterize the infiltration time of water in the interconnected pores. Calculate the permeability coefficient of the target detection point based on the segmented slope and the permeation time constant; Obtaining the compaction degree of the target detection point includes: The equivalent dielectric constant of the target detection point in the water-bearing state after water spraying is determined based on the ground-penetrating radar data after water spraying; the equivalent dielectric constant in the water-bearing state is used to characterize the dielectric polarization strength of the road surface material at the target detection point in the water-bearing state; The equivalent dielectric constant is corrected based on the transverse wave propagation data and longitudinal wave propagation data in the ultrasonic data after water spraying to obtain the equivalent dielectric constant in the dry state; the equivalent dielectric constant in the dry state is used to characterize the corrected dielectric polarization strength of the road surface material at the target detection point. The compaction degree of the target detection point is calculated based on the ultrasonic data after water spraying, the equivalent dielectric constant of the dry state, and the permeability coefficient of the target detection point.

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