Nonlinear evaluation method, system and device for freeze-thaw damage of hydraulic asphalt concrete

Abstract

The application provides a kind of water engineering asphalt concrete freeze-thaw damage nonlinear evaluation method, system and equipment, it is related to freeze-thaw damage evaluation technical field, the evaluation method is by constructing the comprehensive damage index model containing nonlinear coupling term, the synergistic degradation of each macroscopic performance index of water engineering asphalt concrete in the process of freeze-thaw damage is quantified in evaluation system for the first time, overcome the defect that traditional linear weighting method can only carry out simple superposition, cannot reflect the internal physical connection of damage;At the same time, the nonlinear damage degree function is used to calculate each single damage degree, which can more accurately depict the nonlinear acceleration characteristics of damage with freeze-thaw cycle development, avoid the problem that single index or linear model is not sensitive to early damage and has large deviation in predicting late damage;Finally, the comprehensive damage index calculated based on the model can more comprehensively and more in line with the physical actuality reflect the overall damage state of material.

Description

Technical Field

[0001] This invention relates to the field of freeze-thaw damage assessment technology, and more specifically, to a nonlinear assessment method, system, and equipment for freeze-thaw damage of hydraulic asphalt concrete. Background Technology

[0002] Currently, the assessment of freeze-thaw durability of hydraulic asphalt concrete mainly focuses on two types of methods: Single-index judgment method: This is the most traditional and widely used method. It typically selects uniaxial compressive strength as the core index, comparing the strength loss rate of specimens after freeze-thaw cycles to determine whether the material is qualified or to measure its degree of damage. Some studies also use mass loss rate or dynamic elastic modulus (related to longitudinal wave velocity) as auxiliary criteria. Multi-index linear weighted method: To overcome the limitations of a single index, recent studies have begun to consider multiple indices comprehensively. A typical approach is to measure multiple macroscopic performance indices of specimens after freeze-thaw cycles (such as uniaxial compressive strength, longitudinal wave velocity, permeability coefficient, and mass), then assign an empirical weight to each index, and finally obtain a comprehensive score or index through linear weighted summation for relative comparison and evaluation.

[0003] However, the relevant technologies have the following problems and drawbacks: the single-index judgment method only assesses damage from one dimension and cannot comprehensively reflect the multidimensional degradation of material properties. For example, strength loss often occurs after microstructural damage has accumulated to a certain extent, resulting in a serious lag in the assessment results and making it difficult to effectively warn of early potential damage.

[0004] Furthermore, the freeze-thaw damage evolution process of materials typically exhibits significant nonlinear characteristics, especially during the accelerated damage phase. Existing methods (whether single-index methods or linear weighted methods) mostly use linear or simple proportional relationships to describe the degree of damage, which cannot accurately characterize this nonlinear damage accumulation and evolution process from quantitative to qualitative change. This leads to significant deviations in the accurate judgment of damage status, prediction of development stages, and estimation of remaining life. Summary of the Invention

[0005] The problem solved by this invention is one or more of the aforementioned related technical problems.

[0006] To address the above problems, this invention provides a nonlinear assessment method, system, and equipment for freeze-thaw damage of hydraulic asphalt concrete.

[0007] In a first aspect, the present invention provides a nonlinear assessment method for freeze-thaw damage of hydraulic asphalt concrete, comprising: Freeze-thaw cycle tests were conducted on hydraulic asphalt concrete specimens to obtain macroscopic performance indicators at multiple freeze-thaw cycle points. The individual damage degree corresponding to each macroscopic performance index at each freeze-thaw cycle node is determined by a preset nonlinear damage degree function. A comprehensive damage index model is constructed, which includes at least a linear weighting term for each of the individual damage degrees and a nonlinear coupling term for characterizing the synergistic degradation effect between different individual damage degrees. Based on the comprehensive damage index model, the corresponding comprehensive damage index is obtained according to the individual damage degree corresponding to each of the freeze-thaw cycle number nodes. The freeze-thaw damage status of the hydraulic asphalt concrete specimens is graded and evaluated based on the comprehensive damage index corresponding to each freeze-thaw cycle number node.

[0008] Optionally, the macroscopic performance index includes uniaxial compressive strength, and the individual damage degree includes strength damage degree; determining the individual damage degree corresponding to each freeze-thaw cycle node through a preset nonlinear damage degree function includes: The strength damage degree is determined by Equation 1 based on the uniaxial compressive strength, the initial compressive strength, and the material sensitivity coefficient. Wherein, Equation 1 is: ; in, The strength damage degree corresponds to the number of freeze-thaw cycles (node ​​n), and m is the material sensitivity coefficient. The initial compressive strength is... The uniaxial compressive strength is the number of freeze-thaw cycles corresponding to node n.

[0009] Optionally, the macroscopic performance index further includes longitudinal wave velocity, and the individual damage degree further includes wave velocity damage degree; determining the individual damage degree corresponding to each freeze-thaw cycle node through a preset nonlinear damage degree function further includes: The wave velocity damage degree is determined by Equation 2 based on the longitudinal wave velocity and the initial wave velocity. Wherein, Equation 2 is: ; in, The wave velocity damage degree corresponding to the node n of the freeze-thaw cycle number. The longitudinal wave velocity corresponding to node n of the freeze-thaw cycle number. The initial wave velocity, This represents the acceleration effect coefficient of microcracks.

[0010] Optionally, the macroscopic performance index further includes the permeability coefficient, and the individual damage degree further includes the permeability damage degree; determining the individual damage degree corresponding to each freeze-thaw cycle node by using a preset nonlinear damage degree function further includes: The degree of permeation damage is determined using Equation 3, based on the permeability coefficient and the initial permeability coefficient. Equation 3 is as follows: ; in, The degree of permeability damage corresponding to node n, representing the number of freeze-thaw cycles. The initial permeability coefficient is... This is the shape control factor. The permeability coefficient is the number of freeze-thaw cycles corresponding to node n.

[0011] Optionally, the macroscopic performance indicators further include measured mass values, and the individual damage degree further includes mass damage degree; determining the individual damage degree corresponding to each freeze-thaw cycle node through a preset nonlinear damage degree function further includes: The degree of mass damage is determined by Equation 4 based on the measured mass value and the initial mass. Equation four is as follows: ; in, The quality damage degree corresponding to the node n of the freeze-thaw cycle number. The measured mass value corresponding to node n of the freeze-thaw cycle count. The initial mass is denoted as .

[0012] Optionally, obtaining the corresponding comprehensive damage index based on the individual damage degree corresponding to each of the freeze-thaw cycle number nodes includes: Based on the comprehensive damage index model, the comprehensive damage index under the corresponding freeze-thaw state is obtained according to the strength damage degree, the wave velocity damage degree, the penetration damage degree and the mass damage degree. The comprehensive damage index model includes: ; in, The comprehensive damage index corresponding to node n of the freeze-thaw cycle count. These are the corresponding weight coefficients. The wave velocity damage degree corresponding to the node n of the freeze-thaw cycle number. The degree of permeability damage corresponding to node n, representing the number of freeze-thaw cycles. The quality damage degree corresponding to the node n of the freeze-thaw cycle number. The strength damage degree corresponds to node n, which represents the number of freeze-thaw cycles.

[0013] Optionally, the step of classifying and evaluating the freeze-thaw damage state of the hydraulic asphalt concrete specimen based on the corresponding comprehensive damage index includes: When the comprehensive damage index is less than the first preset value, the freeze-thaw damage state of the hydraulic asphalt concrete specimen is evaluated as the first-level initial stage. When the comprehensive damage index is greater than or equal to the first preset value and less than the second preset value, the freeze-thaw damage state of the hydraulic asphalt concrete specimen is evaluated as the second-level accelerated period. When the comprehensive damage index is greater than or equal to the second preset value and less than the third preset value, the freeze-thaw damage state of the hydraulic asphalt concrete specimen is evaluated as Level 3 rapid development stage. When the comprehensive damage index is greater than or equal to the third preset value, the freeze-thaw damage state of the hydraulic asphalt concrete specimen is evaluated as level four failure period. Wherein, the third preset value is greater than the second preset value, and the second preset value is greater than the first preset value.

[0014] Optionally, the nonlinear assessment method for freeze-thaw damage of hydraulic asphalt concrete further includes: Based on the number of freeze-thaw cycles and the corresponding comprehensive damage index, a damage evolution model is established through nonlinear regression.

[0015] Secondly, the present invention provides a nonlinear evaluation system for freeze-thaw damage of hydraulic asphalt concrete, comprising: The test unit is used to conduct freeze-thaw cycle tests on hydraulic asphalt concrete specimens and obtain macroscopic performance indicators at multiple freeze-thaw cycle nodes. The calculation unit is used to determine the individual damage degree corresponding to each of the macroscopic performance indicators at each of the freeze-thaw cycle number nodes through a preset nonlinear damage degree function. The processing unit is used to construct a comprehensive damage index model, which includes at least a linear weighting term for each individual damage degree and a nonlinear coupling term for characterizing the synergistic degradation effect between different individual damage degrees; based on the comprehensive damage index model, the corresponding comprehensive damage index is obtained according to the individual damage degree corresponding to each freeze-thaw cycle number node. The evaluation unit is used to classify and evaluate the freeze-thaw damage status of the hydraulic asphalt concrete specimen based on the comprehensive damage index corresponding to each freeze-thaw cycle number node.

[0016] Thirdly, the present invention provides a nonlinear assessment device for freeze-thaw damage of hydraulic asphalt concrete, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the nonlinear assessment method for freeze-thaw damage of hydraulic asphalt concrete as described in the first aspect.

[0017] The beneficial effects of the nonlinear assessment method, system, and equipment for freeze-thaw damage of hydraulic asphalt concrete of the present invention are as follows: By constructing a comprehensive damage index model incorporating nonlinear coupling terms, this study, for the first time, quantifies the synergistic deterioration effect of various macroscopic performance indicators (such as permeability, wave velocity, and strength) of hydraulic asphalt concrete during freeze-thaw damage in an evaluation system. This overcomes the shortcomings of traditional linear weighting methods, which can only perform simple superposition and cannot reflect the intrinsic physical correlation of damage. Simultaneously, by employing a nonlinear damage degree function to calculate the damage degree of each individual indicator, it can more accurately characterize the nonlinear acceleration characteristics of damage development with freeze-thaw cycles, avoiding the problems of single indicators or linear models being insensitive to early damage and having large prediction deviations for later damage. Ultimately, the comprehensive damage index calculated based on this model can more comprehensively and realistically reflect the overall damage state of the material, and can provide intuitive and accurate decision-making basis for engineering maintenance through graded assessment, achieving an upgrade from static indicator evaluation to dynamic damage evolution process assessment. Attached Figure Description

[0018] Figure 1 This is a flowchart illustrating a nonlinear assessment method for freeze-thaw damage of hydraulic asphalt concrete according to an embodiment of the present invention. Figure 2 This is a schematic diagram of an exponential form fitting curve according to an embodiment of the present invention; Figure 3 This is a schematic diagram of a power-law form fitting curve according to an embodiment of the present invention; Figure 4 This is a schematic diagram of a cubic polynomial fitting curve according to an embodiment of the present invention. Figure 5 This is a schematic diagram of an exponential form fitting curve according to an embodiment of the present invention; Figure 6 This is a schematic diagram of a nonlinear assessment system for freeze-thaw damage of hydraulic asphalt concrete according to an embodiment of the present invention. Detailed Implementation

[0019] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Although some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the accompanying drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0020] It should be understood that the various steps described in the method embodiments of the present invention may be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present invention is not limited in this respect.

[0021] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; and the term "optionally" means "optional embodiments". Definitions of other terms will be given in the following description. It should be noted that the concepts of "first," "second," etc., mentioned in this invention are used only to distinguish different devices, modules, or units, and are not intended to limit the order of functions performed by these devices, modules, or units or their interdependencies.

[0022] It should be noted that the terms "a" and "a plurality of" used in this invention are illustrative rather than restrictive. Those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0023] The names of the messages or information exchanged between the multiple devices in the embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of these messages or information.

[0024] While the multi-index linear weighted method considers multiple factors, its comprehensive model is essentially a linear superposition of the damage degrees of each index. This method neglects the inherent physical connections and mutually reinforcing effects of various performance indices during the freeze-thaw damage process. For example, an increase in the permeability coefficient exacerbates water intrusion, thereby accelerating the development of internal microcracks and the loss of structural strength. This "coupling effect" cannot be reflected in existing linear weighted models, leading to a disconnect between the assessment results and the actual physical damage process, resulting in unclear physical meaning.

[0025] To address the problems existing in the aforementioned related technologies, embodiments of the present invention provide a nonlinear assessment method, system, and equipment for freeze-thaw damage of hydraulic asphalt concrete.

[0026] like Figure 1 As shown in the figure, an embodiment of the present invention provides a nonlinear assessment method for freeze-thaw damage of hydraulic asphalt concrete, comprising: Step S100: Conduct freeze-thaw cycle tests on hydraulic asphalt concrete specimens to obtain multiple macroscopic performance indicators at multiple freeze-thaw cycle counts.

[0027] Specifically, standardized freeze-thaw cycle tests were conducted on hydraulic asphalt concrete specimens, and their macroscopic performance data (macroscopic performance indicators) were systematically obtained at multiple key freeze-thaw nodes.

[0028] First, based on the engineering environment or relevant specifications, a reasonable freeze-thaw cycle regime is established (e.g., freeze-thaw cycles between -20℃ and +10℃ or between -3℃ and +3℃), and standard specimens are subjected to cyclic treatment. During the test, monitoring is not continuous; instead, the test is paused at a pre-set series of freeze-thaw cycle points (e.g., every 25 or 50 cycles… n=0, 25, 50…), and a series of multi-dimensional, non-destructive or micro-destructive performance tests are performed on the specimens. These tests aim to obtain macroscopic performance index data (e.g., uniaxial compressive strength, longitudinal wave velocity, permeability, etc.) that reflect multiple aspects such as material mechanical integrity, internal structural state, permeability, and apparent quality. Complete raw data must be recorded for each test, and correlation with baseline data in the initial (0 cycles) state must be ensured. In this way, a discrete dataset covering the entire damage development process, containing multi-dimensional performance indicators, and possessing clear time-series characteristics is ultimately obtained.

[0029] By designing systematic freeze-thaw cycle tests and planned multi-node data acquisition, a high-quality, multi-dimensional, time-series-characteristic foundational dataset was constructed for this evaluation method. This dataset not only comprehensively captures the multifaceted performance responses of materials at different damage stages, but more importantly, its discretized, multi-index time-series data characteristics provide the essential data foundation for subsequent steps such as nonlinear damage degree calculation, constructing a comprehensive model including coupling terms, and fitting damage evolution curves. Compared to the potential problems of single test indicators or sparse data points in traditional methods, this step ensures the accuracy and reliability of subsequent nonlinear evaluations, making it possible to move from "point" evaluation to "process" prediction.

[0030] Step S200: Determine the individual damage degree corresponding to each macroscopic performance index under each freeze-thaw cycle node using a preset nonlinear damage degree function.

[0031] Specifically, the test values ​​of various macroscopic performance indicators are transformed into standardized, dimensionless individual damage values. The core of this process lies in the mapping calculation of each type of macroscopic performance indicator (e.g., indicators reflecting load-bearing capacity, internal structure, permeability, etc.) using a function specifically designed for it, possessing a particular nonlinear mathematical form. These functions are not simple linear proportional relationships; rather, their curve shapes (e.g., exponential growth, saturation approach, accelerated rise, etc.) are derived from physical mechanisms or calibrated using experimental data, enabling a more accurate simulation of the indicator's true response behavior during actual freeze-thaw damage. For example, for some indicators sensitive to early micro-damage, the function may have a larger gradient in the early stages of damage to amplify small changes; for indicators whose performance deteriorates rapidly after entering the decay stage, the function may include an accelerating term. Through this step, all the original indicator data, with different physical meanings and dimensions, are uniformly transformed into comparable damage values ​​between 0 (no damage) and 1 (complete failure), thereby achieving an independent and accurate quantitative description of the damage state of materials in different dimensions.

[0032] By tailoring nonlinear damage degree functions for performance indicators with different physical meanings, an intelligent and precise mapping from raw test values ​​to damage degree values ​​is achieved. This method overcomes the shortcomings of traditional linear proportional methods (such as simple loss rate) in failing to characterize the nonlinear evolution of damage, enabling the calculation results to more realistically reflect the actual physical nature of material damage. Specifically, it can: on the one hand, keenly capture and amplify the subtle changes of certain key indicators in the early stages of damage, solving the problem of insensitive early warning; on the other hand, it can accurately describe the accelerated degradation trend of performance in the middle and later stages of damage, avoiding the underestimation of the later damage degree by linear models. Finally, the individual damage degrees output in this step are not only standardized and comparable, but also have clear physical meanings and are synchronized with the damage process, laying a reliable data foundation for the subsequent steps of comprehensively evaluating the synergistic effects between indicators.

[0033] Step S300: Construct a comprehensive damage index model. Based on the comprehensive damage index model, obtain the corresponding comprehensive damage index according to the individual damage degree corresponding to each of the freeze-thaw cycle number nodes. The comprehensive damage index model includes at least a linear weighted term for each of the individual damage degrees and a nonlinear coupling term for characterizing the synergistic degradation effect between different individual damage degrees.

[0034] Specifically, an innovative comprehensive damage index model is constructed and applied. Its core lies in the systematic integration of multiple individual damage degrees calculated in step S200 through a mathematical framework that goes beyond simple linear superposition. This model not only includes linear weighting terms reflecting the contributions of each independent index, but its key innovation is the introduction of specially designed nonlinear coupling terms. These coupling terms typically manifest as the product of two or more individual damage degrees or other nonlinear combinations. Their design is based on the physical mechanism of freeze-thaw damage, used to quantitatively characterize the synergistic aggravation or chain reaction effects between different damage dimensions. For example, a coupling term might aim to quantify the mutually reinforcing relationship between "deterioration of internal connectivity" and "increased permeability." During calculation, a set of individual damage degree values ​​obtained at each freeze-thaw cycle node is substituted into the model, and a single, normalized comprehensive damage index is output through a single comprehensive calculation. This index, as a holistic scalar, aims to more comprehensively and profoundly characterize the overall damage state of the material at that node.

[0035] By constructing a comprehensive damage index model incorporating nonlinear coupling terms, a mathematical characterization of the "systematic deterioration" characteristics of freeze-thaw damage in hydraulic asphalt concrete was achieved for the first time in an evaluation system. This model breaks through the traditional multi-index method's limitation to a linear superposition paradigm of "parallel indexes," enabling the quantification of the inherent physical correlations and mutual promotion effects (such as penetration inducing cracking, which in turn further exacerbates penetration) among various performance indices during the damage process. This makes the final calculated comprehensive damage index not merely a simple summary of index information, but rather reflects the overall state of damage evolution as a system, thus greatly improving the consistency between the evaluation results and the actual physical damage process of the material. Therefore, the comprehensive damage index output by this model has a clearer physical meaning, can more sensitively and accurately reflect the evolution stage of damage, and in particular, can provide earlier warnings of accelerated damage risks caused by vicious cycles between indices, offering a far more reliable basis for engineering decision-making than traditional linear methods.

[0036] Step S400: The freeze-thaw damage status of the hydraulic asphalt concrete specimen is graded and evaluated based on the comprehensive damage index corresponding to each freeze-thaw cycle number node.

[0037] Specifically, based on the comprehensive damage index calculated in step S300 and corresponding to each freeze-thaw cycle node, the freeze-thaw damage status of the specimen is qualitatively graded and assessed. The core of this process lies in mapping continuous comprehensive damage index values ​​to a finite number of discrete damage levels according to a pre-established grading standard closely linked to engineering safety and maintenance decisions. For example, based on different threshold ranges of the index values, the status can be divided into several levels with clear engineering significance, ranging from "basically intact" to "severely damaged." This grading standard comprehensively considers the stage characteristics of damage development, the nonlinear response of the index, and the acceptable risk level for the engineering. Ultimately, the output is no longer an isolated numerical value, but a clear qualitative conclusion about the damage status (e.g., "mild damage, enhanced monitoring recommended"), thus transforming the complex mathematical model calculation results into an intuitive and operable engineering judgment.

[0038] By mapping quantitative comprehensive damage indices to qualitative, graded damage states, the assessment results are greatly simplified and made practical for engineering applications. It effectively bridges the cognitive gap between complex mathematical models and on-site engineering decisions, enabling technicians and managers to quickly and accurately grasp the structural safety status and urgency without delving into model details. This graded assessment not only provides a "health diagnosis" label for material properties, but more importantly, each grade typically corresponds directly to recommended "engineering countermeasures" (such as routine inspections, preventative maintenance, or emergency repairs), thus forming a closed-loop guidance from "condition identification" to "maintenance action," significantly improving the practical application value and decision support efficiency of the assessment method.

[0039] In this embodiment, by constructing a comprehensive damage index model that includes nonlinear coupling terms, the synergistic deterioration effect of various macroscopic performance indicators (such as permeability, wave velocity, and strength) of hydraulic asphalt concrete during the freeze-thaw damage process is quantified for the first time in the evaluation system. This overcomes the shortcomings of traditional linear weighting methods, which can only perform simple superposition and cannot reflect the intrinsic physical correlation of damage. At the same time, by using a nonlinear damage degree function to calculate the damage degree of each individual item, the nonlinear acceleration characteristics of damage development with freeze-thaw cycles can be more accurately characterized, avoiding the problems of single index or linear model being insensitive to early damage and having large deviations in predicting later damage. Finally, the comprehensive damage index calculated based on this model can more comprehensively and more in line with physical reality reflect the overall damage state of the material, and can provide intuitive and accurate decision-making basis for engineering maintenance through graded evaluation, realizing the upgrade from static index evaluation to dynamic damage evolution process evaluation.

[0040] Optionally, the macroscopic performance index includes uniaxial compressive strength, and the individual damage degree includes strength damage degree; determining the individual damage degree corresponding to each freeze-thaw cycle node through a preset nonlinear damage degree function includes: The strength damage degree is determined by Equation 1 based on the uniaxial compressive strength, the initial compressive strength, and the material sensitivity coefficient. Wherein, Equation 1 is: ; in, The strength damage degree corresponds to the number of freeze-thaw cycles (node ​​n), and m is the material sensitivity coefficient. The initial compressive strength is... The uniaxial compressive strength is the number of freeze-thaw cycles corresponding to node n.

[0041] Optionally, the macroscopic performance index further includes longitudinal wave velocity, and the individual damage degree further includes wave velocity damage degree; determining the individual damage degree corresponding to each freeze-thaw cycle node through a preset nonlinear damage degree function further includes: The wave velocity damage degree is determined by Equation 2 based on the longitudinal wave velocity and the initial wave velocity. Wherein, Equation 2 is: ; in, The wave velocity damage degree corresponding to the node n of the freeze-thaw cycle number. The longitudinal wave velocity corresponding to node n of the freeze-thaw cycle number. The initial wave velocity, This represents the acceleration effect coefficient of microcracks.

[0042] Optionally, the macroscopic performance index further includes the permeability coefficient, and the individual damage degree further includes the permeability damage degree; determining the individual damage degree corresponding to each freeze-thaw cycle node by using a preset nonlinear damage degree function further includes: The degree of permeation damage is determined using Equation 3, based on the permeability coefficient and the initial permeability coefficient. Equation 3 is as follows: ; in, The degree of permeability damage corresponding to node n, representing the number of freeze-thaw cycles. The initial permeability coefficient is... This is the shape control factor. The permeability coefficient is the number of freeze-thaw cycles corresponding to node n.

[0043] Optionally, the macroscopic performance indicators further include measured mass values, and the individual damage degree further includes mass damage degree; determining the individual damage degree corresponding to each freeze-thaw cycle node through a preset nonlinear damage degree function further includes: The degree of mass damage is determined by Equation 4 based on the measured mass value and the initial mass. Equation four is as follows: ; in, The quality damage degree corresponding to the node n of the freeze-thaw cycle number. The measured mass value corresponding to node n of the freeze-thaw cycle count. The initial mass is denoted as .

[0044] In some embodiments, when calculating the strength damage degree, the material sensitivity coefficient m can be taken as 1.2~1.5 (or it can be precisely calibrated by fitting a strength decay curve), reflecting the amplification effect of strength loss on overall damage. Strength damage degree is a core indicator of the load-bearing capacity of asphalt concrete. In the early stages of freeze-thaw cycles, micro-defects have little impact on the strength damage degree; however, when defects accumulate to a certain extent, they will cause stress concentration, leading to an accelerated decrease in the strength damage degree. This nonlinear damage characteristic cannot be explained by a simple linear loss rate. Accurate description. Therefore, this embodiment introduces a material sensitivity coefficient m (m>1) to measure the retention rate of strength damage. Perform power operations. When m>1, the function curve is convex upwards, which means that, under the same strength retention rate, the damage degree in the later stage of freeze-thaw is given a higher weight, which is more in line with the physical law of material damage (i.e. the accelerated effect of damage accumulation).

[0045] When calculating wave velocity damage, λ is the microcrack acceleration effect coefficient, defaulting to 0.3. The quadratic term characterizes the accelerated attenuation of wave velocity after microcracks connect. Longitudinal wave velocity is extremely sensitive to microcracks within the material. In the initial stage of freeze-thaw cycles, the formation of isolated micropores causes a linear decrease in wave velocity. As the cycle continues, the microcracks connect to form a network, producing a nonlinear amplification effect on wave velocity attenuation. This invention addresses this issue in the linear term... Based on this, a quadratic term was added. The quadratic term represents the additional damage caused by the connectivity of microcracks. When the wave velocity loss is small, the contribution of the quadratic term is small; when the wave velocity loss increases, the contribution of the quadratic term increases rapidly, thus more accurately characterizing the degradation process of the internal structure.

[0046] When calculating the degree of permeability damage, the permeability coefficient is a key indicator of freeze-thaw damage in hydraulic asphalt concrete. Its variation can span several orders of magnitude and has a fatal impact on structural durability. (Direct use growth rate) This would lead to an excessively large and unstable weight for the indicator in the comprehensive model. This embodiment uses a saturated function for mapping. Its physical meaning is that initial permeability growth contributes significantly to damage, but when permeability is already high, its marginal contribution to the damage state decreases with further growth. The coefficient β controls the shape of the curve mapping permeability growth rate to damage degree. The smaller β is, the "flatter" the curve, indicating that more permeability needs to grow to reach a high damage degree; the larger β is, the "steeper" the curve. For structures with extremely high seepage control requirements (such as asphalt panels and core walls), a larger value (e.g., 0.15-0.20) should be used to more precisely distinguish damage in the low-to-medium permeability stages. For ordinary facing projects, a smaller value (e.g., 0.05-0.1) can be used.

[0047] Optionally, obtaining the corresponding comprehensive damage index based on the individual damage degree corresponding to each of the freeze-thaw cycle number nodes includes: Based on the comprehensive damage index model, the comprehensive damage index under the corresponding freeze-thaw state is obtained according to the strength damage degree, the wave velocity damage degree, the penetration damage degree and the mass damage degree. The comprehensive damage index model includes: ; in, The comprehensive damage index corresponding to node n of the freeze-thaw cycle count. These are the corresponding weight coefficients. The wave velocity damage degree corresponding to the node n of the freeze-thaw cycle number. The degree of permeability damage corresponding to node n, representing the number of freeze-thaw cycles. The quality damage degree corresponding to the node n of the freeze-thaw cycle number. The strength damage degree corresponds to node n, which represents the number of freeze-thaw cycles.

[0048] Specifically, the calculation of the comprehensive damage index is a core process of multi-dimensional information fusion and system simulation. (See formula...) As shown, the calculation does not simply sum the damage values ​​with weights, but constructs a two-layer structure model that includes "independent contributions" and "synergistic effects".

[0049] During the calculation, the four individual damage values ​​(strength damage value, wave velocity damage value, permeability damage value, and mass damage value) obtained from step S200 under the same freeze-thaw cycle number node n are first used as input.

[0050] The first part of the computational model (linear weighting term) This reflects the independent and direct contribution of each indicator to the overall damage. For example, a decrease in strength is directly related to the loss of load-bearing capacity, and a decrease in wave velocity directly reflects the deterioration of the internal structure.

[0051] The second part of the computational model, and its core innovation, consists of two nonlinear coupling terms: This study aims to quantify the mutually reinforcing effect between "increased permeability" and "internal structural damage (decreased wave velocity)." When permeability increases ( When the wave velocity increases, more moisture intrusion exacerbates frost heave and microcrack development, thus accelerating the decrease in wave velocity. (Increase). This only makes a significant contribution to the composite index when both occur simultaneously, simulating a vicious cycle of moisture intrusion and internal cracking.

[0052] This study aims to quantify the weakening effect of increased permeability on structural load-bearing capacity (strength). The increase in permeability channels is not only damage in itself, but also leads to a reduction in the effective load-bearing area of ​​the material and a deterioration of the stress state, thereby accelerating strength loss. (Increase).

[0053] Weighting coefficients ( The determination of the weights is a flexible step. In simple or standard applications, equal weighting (e.g., 0.2 for each) or preset fixed values ​​based on literature and expert experience can be used. To pursue higher accuracy and adaptability, data-driven methods (such as entropy weighting or principal component analysis) can be used to automatically determine the objective weights of each index and coupling term based on a large amount of experimental data, so that the model can adapt to different material ratios or engineering environments.

[0054] For example, in practical applications, considering that the importance of various performance indicators changes at different damage stages, an adaptive weight adjustment method is adopted. Combined with damage state classification, weight combinations corresponding to the four damage levels are established. Based on the level of the real-time calculated comprehensive damage index D, the corresponding weights are dynamically selected, as shown in Table 1. The weights are selected according to the table below: Table 1 Adaptive Weight Coefficient Table

[0055] The specific details of this iterative adjustment process are as follows: Step 1: Calculate the initial D0 value (rapid initial screening): This step quickly and initially locates the current freeze-thaw state. Using a set of universal default weighting coefficients (e.g., assigning equal weights to all linear and nonlinear coupled terms, or using a set of fixed weights determined based on extensive experience), and combining the calculated damage levels (e.g., strength damage, wave velocity damage, permeability damage, and mass damage), a preliminary comprehensive damage index D0 is calculated using a comprehensive damage index model. This D0 value provides an initial estimate of the overall damage level; its core purpose is to provide a basis for subsequent precise grading, rather than being the final assessment result.

[0056] Step 2: Determine the Damage Level (State Identification): Compare the preliminary comprehensive damage index D0 calculated in Step 1 with the preset damage state classification thresholds. For example, compare the comprehensive damage index ranges corresponding to "Initial Stage," "Accelerated Stage," "Rapid Development Stage," and "Failure Stage" (e.g., D < 20%, 20% ≤ D < 40%, etc.). Through this comparison, determine the most likely damage development stage of the specimen. This step maps continuous index values ​​to discrete stage labels with clear physical and engineering significance.

[0057] Step 3: Switch weights and recalculate the final weights Value (precise calculation): This step is the core of dynamic adjustment. Using multiple pre-stored combinations of weighting coefficients (as shown in Table 1), each combination is optimized for a specific damage level. For example: Weighting combinations for the "initial phase" may increase sensitivity to permeability damage and wave velocity damage and their coupling terms, as subtle changes in permeability and internal structural degradation at this stage are key early warning signals.

[0058] For the weighting combination of the "rapid development period" or the "destruction period": the weight of the strength damage degree and its coupling terms may be significantly increased, because at this stage, the loss of structural bearing capacity becomes the primary concern of safety assessment.

[0059] Based on the damage level determined in step 2, the system automatically switches to and uses the preset weighting coefficients corresponding to that level, replacing the default weights in step 1, and re-substitutes them into the comprehensive damage index model for calculation. The value obtained in this calculation is the final comprehensive damage index D, which more accurately reflects the overall state at the current damage stage.

[0060] This iterative adjustment mechanism implements a dynamic assessment strategy of "preliminary positioning - precise calculation." Its core objective is to enable the assessment model to adapt to different stages of material damage development, highlighting the indicators and interactions that best reflect the key degradation mechanisms and engineering risks at each stage. This overcomes the limitation of using a single fixed weight to comprehensively and accurately characterize the damage evolution throughout the entire life cycle, thereby significantly improving the assessment accuracy, physical consistency, and engineering guidance value of the comprehensive damage index at different stages.

[0061] Finally, by substituting all terms into the formula and performing a weighted sum, we obtain the comprehensive damage index at the freeze-thaw node n. This value is a scalar between 0 and 1 (or expressed as a percentage), which integrates all damage information from the four dimensions and their interactions.

[0062] This embodiment introduces a subset and The comprehensive index model with nonlinear coupling terms has, for the first time, mathematically quantified the chain reaction and synergistic degradation physical processes of freeze-thaw damage in an evaluation system. This upgrades the evaluation from the traditional "static index parallelism" to "dynamic system simulation." The comprehensive damage index not only reflects the independent degradation degree of each index but also characterizes the real damage chain of "penetration initiating cracking, and cracking and penetration jointly weakening strength." The evaluation conclusions are highly consistent with the macroscopic degradation phenomena of the specimens. Furthermore, the coupling term design amplifies the early signals of interactions between key indicators (such as the correlation between initial slight changes in permeability and microcrack development), enabling earlier identification of potential accelerated damage risks and overcoming the lag in early warning of traditional methods. Simultaneously, the model is highly adaptable and interpretable: by flexibly determining the weighting coefficients (fixed values ​​or data-driven), the model can be adapted to different engineering requirements and material properties. Its clear mathematical structure facilitates understanding and trust among engineering technicians, strongly supporting maintenance decisions based on evaluation results.

[0063] Optionally, the step of classifying and evaluating the freeze-thaw damage state of the hydraulic asphalt concrete specimen based on the corresponding comprehensive damage index includes: When the comprehensive damage index is less than the first preset value, the freeze-thaw damage state of the hydraulic asphalt concrete specimen is evaluated as the first-level initial stage. When the comprehensive damage index is greater than or equal to the first preset value and less than the second preset value, the freeze-thaw damage state of the hydraulic asphalt concrete specimen is evaluated as the second-level accelerated period. When the comprehensive damage index is greater than or equal to the second preset value and less than the third preset value, the freeze-thaw damage state of the hydraulic asphalt concrete specimen is evaluated as Level 3 rapid development stage. When the comprehensive damage index is greater than or equal to the third preset value, the freeze-thaw damage state of the hydraulic asphalt concrete specimen is evaluated as level four failure period. Wherein, the third preset value is greater than the second preset value, and the second preset value is greater than the first preset value.

[0064] In some embodiments, the evaluation process typically employs a four-level classification system: Level 1 initial stage: when When the value is below the first preset value (e.g., 20%), it is considered to be in a basically intact state. At this stage, although the material properties may fluctuate slightly, they are generally stable and the damage develops slowly.

[0065] Secondary acceleration period: when When the damage reaches or exceeds the first preset value but falls below the second preset value (e.g., 40%), the system is considered to have entered the acceleration phase. This phase signifies that damage begins to accumulate and exhibits an accelerating trend, and internal micro-defects begin to interact with each other.

[0066] The third stage of rapid development: when When the value reaches or exceeds the second preset value but falls below the third preset value (e.g., 60%), the system is considered to have entered a rapid development phase. At this stage, damage is significant, performance degradation accelerates markedly, and the emergence of macroscopic defects may occur.

[0067] Level 4 Disruption Period: When When the material reaches or exceeds the third preset value, it is considered to be in a period of severe damage or failure. At this stage, the material properties have severely degraded, and it may lose its main functions (such as seepage prevention and load-bearing capacity), posing a potential safety hazard to the project. For example, as shown in Table 2... In some embodiments, as shown in Table 2, the damage status determination table... Table 2 Damage Status Assessment Table

[0068] The threshold setting options are as follows: Empirical statistical method: Based on a large amount of freeze-thaw test data of similar materials and environments, analyze the comprehensive damage index. The distribution of the material was correlated with the actual macroscopic deterioration phenomena (such as the appearance of visible cracks and a sharp increase in permeability), and the threshold values ​​for each stage were statistically determined.

[0069] Performance inflection point correlation method: combining individual damage degree curves or comprehensive index evolution curves The mathematical characteristics (such as the inflection points of the first and second derivatives) are used to set the threshold near the critical point where the dynamic behavior of damage development changes significantly.

[0070] Standard and Safety Factor Method: Based on the minimum requirements for material properties in relevant engineering standards, a safety factor is introduced to deduce the corresponding comprehensive damage index threshold. For example, the threshold value corresponding to a strength retention rate lower than the standard requirement is used. The value is set as a "warning" or "damage" threshold.

[0071] Project Importance Customization: For particularly important projects (such as the core seepage prevention body of a reservoir dam), the safety margin can be increased, that is, the threshold of each level can be lowered (for example, the "early warning period" threshold can be reduced from 40% to 30%), so as to achieve earlier and more conservative early warning.

[0072] By establishing a clearly tiered damage status assessment standard directly linked to the comprehensive damage index, the complex nonlinear mathematical model calculation results have been successfully translated into intuitive, clear, and operable engineering language. This tiered system assigns corresponding "engineering countermeasures" recommendations (such as "strengthen monitoring," "planned maintenance," "recommend repair," and "immediate replacement") to each damage level, enabling engineering managers to make rapid maintenance management decisions without interpreting complex data, greatly improving the practicality and action guidance of the assessment results. Simultaneously, the comprehensive index calculated based on the nonlinear model can capture damage acceleration signals earlier. Combined with tiered descriptions such as "acceleration phase" and "rapid development phase," it enables early warning and tiered early warning of damage, buying valuable time for preventative maintenance measures and transforming passive response into proactive prevention. Furthermore, the unified tier classification (such as Levels I, II, III, and IV) and status descriptions facilitate clear and unambiguous communication regarding structural health status among personnel from different professional backgrounds (such as researchers, testing personnel, and maintenance managers), promoting standardized management and archiving of assessment results.

[0073] Optionally, when classifying and evaluating the freeze-thaw damage state of hydraulic asphalt concrete specimens based on the comprehensive damage index, the damage development rate, a dynamic parameter, can be further incorporated for comprehensive judgment. The damage development rate can be obtained by calculating the rate of change of the comprehensive damage index between adjacent freeze-thaw cycle nodes, reflecting the speed trend of damage accumulation.

[0074] Specifically, based on the existing single threshold classification of the comprehensive damage index, a consideration of the damage development rate can be added to form a more refined and dynamic assessment rule. For example, even if the comprehensive damage index has entered a certain level range (e.g., less than 20% of the first preset value), if its corresponding damage development rate is also lower than a set safety threshold (e.g., 0.3% per cycle), it can be more confidently assessed that it is in a stable initial stage. Conversely, if the index is low but the rate has significantly exceeded the safety threshold, it may indicate a risk of premature damage acceleration, requiring attention and adjustment of the assessment conclusion or monitoring strategy. The rate threshold can be set and adjusted according to material properties, engineering importance, and historical data statistical analysis.

[0075] By incorporating the damage development rate into the classification, the status assessment is not only based on the "current state" of the damage, but also takes into account the "trend of change" of the damage, thereby enabling early warning of the future development of the damage and more accurate stage judgment, thus improving the foresight and reliability of the assessment.

[0076] Optionally, the nonlinear assessment method for freeze-thaw damage of hydraulic asphalt concrete further includes: Based on the number of freeze-thaw cycles and the corresponding comprehensive damage index, a damage evolution model is established through nonlinear regression.

[0077] Specifically, data preparation: the input data consists of a series of ordered data pairs (n, ...). ), where n is the number of freeze-thaw cycles (e.g., 0, 25, 50, ... times). This represents the final comprehensive damage index for the corresponding node obtained in step S300. These data constitute a discrete observation sequence of damage development over time (number of freeze-thaw cycles).

[0078] Model selection and fitting: Candidate Model Library: Based on the general physical laws of damage development (such as slow initial accumulation, mid-term acceleration, and potential stabilization in the later stage), it provides a variety of alternative nonlinear function forms for fitting. Common candidate models include, but are not limited to: exponential form, power-law form, polynomial form (such as cubic polynomial), etc.

[0079] Fitting and Optimization: Nonlinear regression algorithms (such as least squares) are used to fit candidate models to (n, On the data sequence. Subsequently, based on goodness of fit (e.g., R... 2 Value), physical rationality of the model (e.g.) The optimal model is selected as the damage evolution equation for this specific material by comprehensively evaluating factors such as whether the parameter should be 0, whether there is a theoretical upper limit, and the physical interpretability of the parameters. .

[0080] Model application example: Trend analysis and inflection point identification: plotting The curve allows for a direct observation of the overall trend of damage development, and the inflection point from linear accumulation to accelerated development of damage can be identified by calculating the first derivative (damage rate) or the second derivative.

[0081] Lifespan prediction: By substituting the estimated total number of freeze-thaw cycles N within the expected design service life or maintenance cycle of the project into the damage evolution equation, the damage state at the end of the service life can be predicted. Alternatively, the operation can be reversed: an acceptable damage index threshold (such as the lower limit corresponding to the "rapid development period") can be set, and the number of freeze-thaw cycles required to reach that threshold can be solved by inverse equation, serving as an early warning indicator for the theoretical remaining lifespan.

[0082] Material selection and design optimization: Identical tests were conducted on asphalt concrete with different mix proportions, and their respective damage evolution equations were established. By comparing characteristic parameters in the equations (such as the acceleration coefficient b in the exponential model, or the number of cycles required to reach the same damage level), material mix proportions with better freeze-thaw resistance and durability can be quantitatively and scientifically evaluated and optimized.

[0083] By establishing a damage evolution model, a key leap has been achieved in assessment methods, moving from discrete "current state diagnosis" to continuous "process prediction." This model can extrapolate and predict the damage state of materials under any number of freeze-thaw cycles based on limited, interim experimental data. This provides a direct quantitative tool for assessing the remaining life of engineering structures and planning preventative maintenance, overcoming the limitations of traditional methods that can only perform post-hoc evaluations of completed cycles. Simultaneously, managers can deploy monitoring and maintenance resources in advance, based on the predicted curve, before the damage acceleration inflection point appears, achieving a strategic shift from "passively responding to failure" to "proactively managing risk." Furthermore, the parameters of the evolution equation (such as the acceleration index) become quantitative indicators characterizing the freeze-thaw durability of materials, providing new and deeper insights and comparative criteria for theoretical research in materials science and the optimal design of engineering materials.

[0084] In one specific embodiment, a freeze-thaw cycle test was conducted on standard specimens of asphalt concrete panels from a reservoir in a high-altitude cold region. The test regime was as follows: temperature was lowered from +10℃ to -20℃ and held for 8 hours; then the temperature was raised from -20℃ to +10℃ and held for 4 hours, constituting one complete cycle. Samples were taken and tested after each freeze-thaw cycle (n = 0, 25, 50, 75, 100, 125, 150, 175, and 200 cycles). The initial values ​​and some key data are shown in Table 3. Table 3 Test Table

[0085] Parameter selection and basis: Material parameters: m=1.25, λ=0.30, β=0.15; Initial weight coefficient: α=0.20, β=0.20, γ=0.20, δ=0.20, ε=0.20 Calculation of individual damage severity and overall damage index (taking n=150 as an example): Strength damage ; Wave velocity damage ; Permeability damage ; Quality damage ; Using the default weights, the initial D is calculated as follows: D0(150) = 0.2 × 0.3658 + 0.2 × 0.4665 + 0.2 × (0.4296 × 0.4665) + 0.2 × (0.4296 × 0.3658) + 0.2 × 0.0880 = 0.2556; Determine the damage level and switch weights: Since 20% < D0(150) < 40%, it belongs to level II damage. Therefore, switch to use the level II weights [0.20, 0.20, 0.30, 0.25, 0.05] to recalculate the final D value.

[0086] Final comprehensive damage index: D c (150) = 0.2×0.3658 + 0.2×0.4665 + 0.3×(0.4296×0.4665) + 0.25×(0.4296*0.3658) + 0.05×0.0880 = 0.2703; 20% < D c (150) = 0.2703 < 40%, belonging to level II damage.

[0087] Similarly, calculate the D(n) values for all freeze-thaw cycle numbers n, as shown in Table 4.

[0088] Table 4 Comprehensive damage index and corresponding damage levels for all freeze-thaw cycle numbers n

[0089] Damage evolution model: Fit the non-linear regression of n (0, 25, 50, 75, 100, 125, 150, 175, 200) with the corresponding percentage values (0.00, 3.0939, 7.68074, 11.6135, 15.9736, 21.5837, 27.0303, 32.6884, 39.5486).

[0090] Fitting candidate equations and results: (1) Exponential form: The corresponding fitting curve is as Figure 2 shown. The fitting equation (damage evolution model) is in the form of: ; Fitted: a = 1.52E-4, b = 1.53, R 2 = 0.9955 (goodness of fit). The parameter b directly reflects the acceleration characteristic (b > 1 indicates acceleration).

[0091] (2) Power-law form: The corresponding fitting curve is as Figure 3 shown. The fitting equation is in the form of: ; Fitted: a = 0.0526, b = 1.24738, R 2 = 0.99864.

[0092] (3) Cubic polynomial form: The corresponding fitting curve is as Figure 4 As shown. The fitting equation is in the form of: ; The fitting yielded: =-0.11058, =0.1355, =2.55232E-4, =2.82413E-7, R 2 =0.99949.

[0093] It can be seen that, although the R of the cubic polynomial 2 The value is the highest, but its physical meaning is slightly lacking when n=0, D(0)=-0.11058. The power-law form of the relationship curve has no upper limit and does not satisfy the condition that the comprehensive damage index approaches 100% when n takes a certain value. The exponential form R²=0.9955 not only satisfies the physical condition of D(0)=0, but also the comprehensive damage index approaches 100% when n takes a certain value; in addition, its shape parameter b=1.53>1 clearly reflects the characteristic of accelerated damage development. Therefore, the exponential form is preferred as the damage evolution equation for this material.

[0094] Analysis and application process, for example: based on the obtained damage evolution equation The analysis can be performed as follows: The shape parameter b=1.53>1 confirms that the freeze-thaw damage process of the asphalt concrete panel exhibits obvious accelerated characteristics rather than nonlinear development.

[0095] The scale parameter a = 0.000152 is relatively small, indicating that the material has acceptable resistance in the early stages of freeze-thaw cycles.

[0096] Plot the Dn curve (e.g.) Figure 5 As shown in the figure, it can be clearly observed that the curve reaches an inflection point around n=160 cycles, and the damage development rate changes from a significantly accelerated stage to a slow growth stage, indicating that as the number of freeze-thaw cycles increases, the internal damage cracks of the material gradually penetrate, and then the damage rate decreases.

[0097] In subsequent applications, management departments can use this equation, inputting the estimated average annual number of freeze-thaw cycles within the planned operating period, to predict the damage index trend after 5 or 10 years. For example, if the region has an average of about 16 freeze-thaw cycles per year, then after 10 years of operation (n=160), the predicted D(160) = 30.11%, which is at the Level II threshold, warning management units to strengthen monitoring and plan maintenance.

[0098] Management can define custom warning lines on the Dn curve based on the importance of the project. For example, D=15 can be set as the "enhanced monitoring line". When the predicted or measured D value approaches this line, more intensive on-site inspections (such as non-destructive thickness measurement and leak point inspection) will be initiated.

[0099] The same test was conducted on asphalt concrete with different mix proportions, and their D(n) equations were established respectively. By comparing the b value (acceleration trend) of each equation and the number of cycles required to reach the same D value, the mix proportion with better freeze-thaw durability can be scientifically selected. For example, if mix proportion B has b=1.2 (slower acceleration) and a smaller a value, its long-term freeze-thaw resistance is better than mix proportion A in this example.

[0100] By combining the damage development trend predicted by the equation with the actual situation of on-site inspection (such as crack survey), a more forward-looking "preventive maintenance" plan can be developed, rather than a passive "repair after damage".

[0101] like Figure 6 As shown in the figure, an embodiment of the present invention provides a nonlinear evaluation system for freeze-thaw damage of hydraulic asphalt concrete. The nonlinear evaluation system for freeze-thaw damage of hydraulic asphalt concrete includes: The test unit is used to conduct freeze-thaw cycle tests on hydraulic asphalt concrete specimens and obtain multiple macroscopic performance indicators at multiple freeze-thaw cycle nodes. The calculation unit is used to determine the individual damage degree corresponding to each of the macroscopic performance indicators at each of the freeze-thaw cycle number nodes through a preset nonlinear damage degree function. The processing unit is used to construct a comprehensive damage index model, which includes at least a linear weighting term for each individual damage degree and a nonlinear coupling term for characterizing the synergistic degradation effect between different individual damage degrees; based on the comprehensive damage index model, the corresponding comprehensive damage index is obtained according to the individual damage degree corresponding to each freeze-thaw cycle number node. The evaluation unit is used to classify and evaluate the freeze-thaw damage status of the hydraulic asphalt concrete specimen based on the comprehensive damage index corresponding to each freeze-thaw cycle number node.

[0102] This invention provides a nonlinear assessment device for freeze-thaw damage of hydraulic asphalt concrete, comprising a memory and a processor; the memory is used to store a computer program; the processor is used to implement the nonlinear assessment method for freeze-thaw damage of hydraulic asphalt concrete as described above when the computer program is executed.

[0103] This invention provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements the nonlinear evaluation method for freeze-thaw damage of hydraulic asphalt concrete as described above.

[0104] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A nonlinear assessment method for freeze-thaw damage of hydraulic asphalt concrete, characterized in that, include: Freeze-thaw cycle tests were conducted on hydraulic asphalt concrete specimens to obtain multiple macroscopic performance indicators at multiple freeze-thaw cycle points. The individual damage degree corresponding to each macroscopic performance index at each freeze-thaw cycle node is determined by a preset nonlinear damage degree function. A comprehensive damage index model is constructed, which includes at least a linear weighting term for each of the individual damage degrees and a nonlinear coupling term for characterizing the synergistic degradation effect between different individual damage degrees. Based on the comprehensive damage index model, the corresponding comprehensive damage index is obtained according to the individual damage degree corresponding to each of the freeze-thaw cycle number nodes. The freeze-thaw damage status of the hydraulic asphalt concrete specimens is graded and evaluated based on the comprehensive damage index corresponding to each freeze-thaw cycle number node.

2. The nonlinear assessment method for freeze-thaw damage of hydraulic asphalt concrete according to claim 1, characterized in that, The macroscopic performance indicators include uniaxial compressive strength, and the individual damage degree includes strength damage degree; determining the individual damage degree corresponding to each freeze-thaw cycle node through a preset nonlinear damage degree function includes: The strength damage degree is determined by Equation 1 based on the uniaxial compressive strength, the initial compressive strength, and the material sensitivity coefficient. Wherein, Equation 1 is: ； in, The strength damage degree corresponds to the number of freeze-thaw cycles (node ​​n), and m is the material sensitivity coefficient. The initial compressive strength is... The uniaxial compressive strength is the number of freeze-thaw cycles corresponding to node n.

3. The nonlinear assessment method for freeze-thaw damage of hydraulic asphalt concrete according to claim 2, characterized in that, The macroscopic performance indicators also include longitudinal wave velocity, and the individual damage degree also includes wave velocity damage degree; the determination of the individual damage degree corresponding to each freeze-thaw cycle node by using a preset nonlinear damage degree function also includes: The wave velocity damage degree is determined by Equation 2 based on the longitudinal wave velocity and the initial wave velocity. Wherein, Equation 2 is: ； in, The wave velocity damage degree corresponding to the node n of the freeze-thaw cycle number. The longitudinal wave velocity corresponding to node n of the freeze-thaw cycle number. The initial wave velocity, This represents the acceleration effect coefficient of microcracks.

4. The nonlinear assessment method for freeze-thaw damage of hydraulic asphalt concrete according to claim 3, characterized in that, The macroscopic performance indicators also include the permeability coefficient, and the individual damage degree also includes the permeability damage degree; the determination of the individual damage degree corresponding to each freeze-thaw cycle node by using a preset nonlinear damage degree function also includes: The degree of permeation damage is determined using Equation 3, based on the permeability coefficient and the initial permeability coefficient. Equation 3 is as follows: ； in, The degree of permeability damage corresponding to node n, representing the number of freeze-thaw cycles. The initial permeability coefficient is... This is the shape control factor. The permeability coefficient is the number of freeze-thaw cycles corresponding to node n.

5. The nonlinear assessment method for freeze-thaw damage of hydraulic asphalt concrete according to claim 4, characterized in that, The macroscopic performance indicators also include measured quality values, and the individual damage degree also includes quality damage degree; the determination of the individual damage degree corresponding to each freeze-thaw cycle node through a preset nonlinear damage degree function also includes: The degree of mass damage is determined by Equation 4 based on the measured mass value and the initial mass. Equation four is as follows: ； in, The quality damage degree corresponding to the node n of the freeze-thaw cycle number. The measured mass value corresponding to node n of the freeze-thaw cycle count. The initial mass is denoted as .

6. The nonlinear assessment method for freeze-thaw damage of hydraulic asphalt concrete according to claim 5, characterized in that, The step of obtaining the corresponding comprehensive damage index based on the individual damage degree corresponding to each of the freeze-thaw cycle number nodes includes: Based on the comprehensive damage index model, the comprehensive damage index under the corresponding freeze-thaw state is obtained according to the strength damage degree, the wave velocity damage degree, the penetration damage degree and the mass damage degree. The comprehensive damage index model includes: ； in, The comprehensive damage index corresponding to node n of the freeze-thaw cycle count. These are the corresponding weight coefficients. The wave velocity damage degree corresponding to the node n of the freeze-thaw cycle number. The degree of permeability damage corresponding to node n, representing the number of freeze-thaw cycles. The quality damage degree corresponding to the node n of the freeze-thaw cycle number. The strength damage degree corresponds to node n, which represents the number of freeze-thaw cycles.

7. The nonlinear assessment method for freeze-thaw damage of hydraulic asphalt concrete according to claim 1, characterized in that, The grading and evaluation of the freeze-thaw damage state of the hydraulic asphalt concrete specimens based on the corresponding comprehensive damage index includes: When the comprehensive damage index is less than the first preset value, the freeze-thaw damage state of the hydraulic asphalt concrete specimen is evaluated as the first-level initial stage. When the comprehensive damage index is greater than or equal to the first preset value and less than the second preset value, the freeze-thaw damage state of the hydraulic asphalt concrete specimen is evaluated as the second-level accelerated period. When the comprehensive damage index is greater than or equal to the second preset value and less than the third preset value, the freeze-thaw damage state of the hydraulic asphalt concrete specimen is evaluated as Level 3 rapid development stage. When the comprehensive damage index is greater than or equal to the third preset value, the freeze-thaw damage state of the hydraulic asphalt concrete specimen is evaluated as level four failure period. Wherein, the third preset value is greater than the second preset value, and the second preset value is greater than the first preset value.

8. The nonlinear assessment method for freeze-thaw damage of hydraulic asphalt concrete according to claim 1, characterized in that, The nonlinear assessment method for freeze-thaw damage of hydraulic asphalt concrete also includes: Based on the number of freeze-thaw cycles and the corresponding comprehensive damage index, a damage evolution model is established through nonlinear regression.

9. A nonlinear evaluation system for freeze-thaw damage of hydraulic asphalt concrete, characterized in that, include: The test unit is used to conduct freeze-thaw cycle tests on hydraulic asphalt concrete specimens and obtain multiple macroscopic performance indicators at multiple freeze-thaw cycle nodes. The calculation unit is used to determine the individual damage degree corresponding to each of the macroscopic performance indicators at each of the freeze-thaw cycle number nodes through a preset nonlinear damage degree function. The processing unit is used to construct a comprehensive damage index model, which includes at least a linear weighting term for each of the individual damage degrees and a nonlinear coupling term for characterizing the synergistic degradation effect between different individual damage degrees. Based on the comprehensive damage index model, the corresponding comprehensive damage index is obtained according to the individual damage degree corresponding to each of the freeze-thaw cycle number nodes. The evaluation unit is used to classify and evaluate the freeze-thaw damage status of the hydraulic asphalt concrete specimen based on the comprehensive damage index corresponding to each freeze-thaw cycle number node.

10. A nonlinear assessment device for freeze-thaw damage of hydraulic asphalt concrete, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements a nonlinear evaluation method for freeze-thaw damage of hydraulic asphalt concrete as described in any one of claims 1 to 8.

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