An asphalt pavement crack repair effect evaluation method based on strong microwave response material

Abstract

This invention discloses a method for evaluating the repair effect of asphalt pavement cracks based on a strong microwave-responsive material. The method involves preparing a repair material with strong microwave response, crack penetration, and interfacial bonding properties; preparing asphalt mixture crack specimens with different degrees of damage and obtaining the initial state of the cracks; filling the crack area with the repair material and activating the repair through microwave heating; obtaining the changes in equivalent crack width, fatigue life, and dissipated energy before and after repair; and constructing a multi-dimensional evaluation method integrating crack morphology recovery, mechanical property recovery, and dissipated energy recovery. By analyzing the differences in repair effects under different damage degrees and microwave heating conditions, the appropriate repair timing and microwave heating parameters are determined. This invention overcomes the limitations of traditional evaluation methods that only focus on the apparent closure state, achieving a comprehensive and quantitative evaluation of crack repair effects, and providing a basis for the application of active repair technology for asphalt pavement cracks and the optimization of maintenance parameters.

Description

Technical Field

[0001] This invention relates to the field of road engineering technology, and in particular to a method for evaluating the repair effect of asphalt pavement cracks based on strong microwave response materials. Background Technology

[0002] During long-term service, asphalt pavements are prone to fatigue cracks and reflective cracks due to factors such as vehicle load cycles, temperature changes, and material aging. The development of cracks compromises the structural integrity of the pavement, reducing its load-bearing capacity and durability. Therefore, achieving efficient and durable repair of cracks is crucial for extending the service life of asphalt pavements. In recent years, active crack repair technology based on strongly microwave-responsive materials has gained increasing attention. This technology utilizes microwave-responsive materials to absorb electromagnetic energy and convert it into heat energy, promoting material flow and interfacial bonding recovery in the cracked area, thus achieving active crack repair. However, with the development of active crack repair technology, accurately evaluating the repair effect has become a significant challenge restricting its application. Existing methods for evaluating crack repair effects mainly focus on geometric characteristics such as crack width changes and apparent closure, primarily reflecting the external recovery state of the crack and failing to characterize the load-bearing capacity and damage recovery level of the repaired cracked area. In reality, the crack repair effect not only manifests in changes in crack morphology but also involves the recovery of structural performance under load and changes in the damage evolution process. Currently, there is a lack of multi-dimensional evaluation methods that integrate crack morphology restoration, mechanical property restoration, and energy dissipation restoration. This makes it difficult to comprehensively and accurately evaluate the repair effect of strong microwave response materials, and also makes it difficult to further determine the appropriate timing for crack repair and microwave heating parameters.

[0003] Existing active repair technologies for asphalt pavement cracks based on highly microwave-responsive materials primarily achieve crack repair by promoting material flow and interfacial bonding recovery in the crack area through microwave heating. However, current evaluation methods mainly rely on single indicators such as crack width change and apparent closure, which cannot comprehensively reflect the recovery status of the structural performance of the crack area after repair. Furthermore, the crack repair effect is influenced by factors such as the initial damage level, material properties, and microwave heating conditions. Current technologies lack an evaluation system that can comprehensively characterize crack morphological recovery, mechanical property recovery, and damage energy recovery, thus failing to achieve accurate quantitative evaluation of the repair effect. Summary of the Invention

[0004] Purpose of the invention: The purpose of this invention is to provide an evaluation method for the repair effect of asphalt pavement cracks based on strong microwave response materials. By constructing a comprehensive evaluation system that integrates morphological recovery, mechanical recovery, and energy recovery, this invention solves the problems of existing crack repair evaluation methods having a single evaluation dimension, being unable to reflect the structural recovery state, and being unable to guide the optimization of repair parameters.

[0005] Technical solution: The present invention provides a method for evaluating the repair effect of asphalt pavement cracks based on strong microwave response materials, comprising the following steps:

[0006] S1. Prepare or provide crack repair materials with strong microwave response performance, crack penetration performance and interfacial bonding performance;

[0007] S2. Prepare asphalt mixture crack specimens with different degrees of damage to obtain initial state information before crack repair;

[0008] S3. The crack area is filled with repair material and the repair process is activated by microwave heating to achieve active crack repair.

[0009] S4. Obtain the characteristics of crack morphology changes, fatigue life changes, and dissipated energy changes before and after repair, and establish a multi-dimensional repair effect evaluation method based on crack morphology recovery, mechanical property recovery, and dissipated energy recovery. Among them, crack morphology recovery characterizes the filling and closing effect of the repair material on the geometric contour of the crack; mechanical property recovery characterizes the recovery effect of the crack area's resistance to fatigue load after repair; and dissipated energy recovery characterizes the recovery effect of the energy dissipation characteristics of the crack area during fatigue damage after repair.

[0010] S5. By analyzing the differences in the multi-dimensional repair effect evaluation results under different crack damage degrees and different microwave heating conditions, the appropriate crack repair timing and microwave heating parameters are determined.

[0011] Furthermore, in step S1, the crack repair material includes emulsified asphalt, electromagnetic response-enhancing particle material, and bonding reinforcement component; the electromagnetic response-enhancing particle material is selected from one or more of iron-based microwave absorbing materials and carbon-based microwave absorbing materials; the bonding reinforcement component is selected from one or more of styrene-butadiene rubber latex, SBS emulsion, silane coupling agent and their composite system, used to improve the bonding performance between the repair material and the crack interface and improve the dispersion stability of the electromagnetic response-enhancing particle material in the emulsified asphalt system.

[0012] Furthermore, in step S1, by adjusting the type, particle size, and dosage of the electromagnetic response-enhancing particulate material, as well as the proportion of the bonding reinforcement component, the crack repair material can meet the preset requirements for microwave response performance, crack penetration performance, interfacial bonding performance, and storage stability.

[0013] Furthermore, in step S2, a semi-circular bending specimen is used to simulate the crack damage state of asphalt pavement. The semi-circular bending specimen is formed by cutting a cylindrical asphalt mixture specimen along its center position, and fatigue load is applied to the notch position of the semi-circular bending specimen for a preset number of times to cause different degrees of crack damage to the specimen. The degree of crack damage is determined according to the ratio of the number of pre-fatigue loading times to the fatigue life of the complete specimen.

[0014] Furthermore, in step S3, the crack repair material is applied to the crack area and penetrates into the crack. A microwave heating device is used to directionally heat the crack area. By adjusting the microwave power, heating time, and heating distance, the crack area reaches the temperature range required for the repair material to soften and flow.

[0015] Furthermore, in step S4, images of the crack area before and after repair are collected, and the outline of the crack area is extracted through image enhancement, binarization processing and edge recognition. The equivalent crack width is determined based on the crack area and the perimeter of the crack boundary, and the degree of crack morphology restoration is determined based on the change in the equivalent crack width before and after repair.

[0016] Furthermore, in step S4, fatigue life is obtained by conducting fatigue loading tests on the cracked specimens before and after repair, and the degree of mechanical property recovery is determined based on the relationship between the remaining fatigue life of the cracked specimen before repair, the fatigue life of the specimen after repair, and the fatigue life of the intact specimen.

[0017] Furthermore, in step S4, the dissipated energy of each loading cycle is determined by the load-displacement curve during the fatigue loading process, the cumulative dissipated energy of the specimen is determined by the sum of the dissipated energy of each loading cycle, and the degree of dissipated energy recovery is determined by the relationship between the cumulative dissipated energy of the cracked specimen before repair, the cumulative dissipated energy of the specimen after repair, and the cumulative dissipated energy of the intact specimen.

[0018] Furthermore, a comprehensive evaluation index for repair effect is constructed based on the degree of crack morphology restoration, mechanical property restoration, and dissipated energy restoration. By assigning corresponding weight coefficients to each degree of restoration and performing weighted summation, the effect of strong microwave response material in repairing asphalt pavement cracks is comprehensively evaluated using the weighted summation result. The weight coefficients are determined using the analytic hierarchy process, expert weighting method, or data analysis method according to the evaluation requirements.

[0019] Furthermore, in step S5, repair tests are conducted on specimens with different degrees of crack damage to obtain the comprehensive repair effect evaluation index corresponding to each damage state. Based on the change law of the comprehensive repair effect evaluation index with the degree of crack damage, the appropriate repair time for active crack repair using strong microwave response material is determined.

[0020] Furthermore, in step S5, crack repair experiments are conducted by setting different microwave output power, heating time, and radiation distance to obtain the comprehensive repair effect evaluation index corresponding to each combination of microwave heating parameters. The correlation between the comprehensive repair effect evaluation index and the microwave heating parameters is established, and the microwave heating parameters suitable for different crack repair conditions are determined with the goal of optimizing the comprehensive repair effect evaluation index.

[0021] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0022] (1) In view of the problem that the evaluation of existing crack repair effects mainly depends on the apparent degree of crack closure, this invention constructs a multi-dimensional evaluation system that integrates crack morphology restoration, mechanical property restoration and energy dissipation restoration, and realizes a comprehensive and quantitative evaluation of the repair effect of strong microwave response materials.

[0023] (2) By simultaneously considering the recovery of crack geometry, structural bearing capacity, and energy dissipation recovery characteristics during fatigue damage, this invention can more comprehensively characterize the structural recovery state after active crack repair, thereby improving the accuracy and reliability of the repair effect evaluation.

[0024] (3) This invention establishes the correlation between the repair effect evaluation results and the degree of crack damage and microwave heating conditions. It can determine the appropriate timing for active crack repair and microwave heating parameters under different service conditions based on the evaluation results, and realize quantitative control and parameter optimization of the crack repair process.

[0025] (4) By establishing a unified evaluation standard for crack repair effect, this invention provides a technical basis for the application evaluation of strong microwave response materials in active repair of cracks in asphalt pavement, thereby improving the scientificity and reliability of the repair technology application process. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the present invention;

[0027] Figure 2 This is a schematic diagram of the preparation of the SCB specimen according to the present invention;

[0028] Figure 3 This is a schematic diagram illustrating the application of the pre-fatigue crack and repair material of the present invention. Detailed Implementation

[0029] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0030] like Figure 1 As shown in the figure, this invention provides a method for evaluating the repair effect of asphalt pavement cracks based on strong microwave response materials, characterized by the following steps:

[0031] S1, Prepare or provide a crack repair material with strong microwave response, crack penetration and interfacial bonding properties; wherein the crack repair material includes emulsified asphalt, electromagnetic response-enhancing particulate material and bonding reinforcement component; wherein the electromagnetic response-enhancing particulate material is composed of one or more of iron-based microwave absorbing materials and carbon-based microwave absorbing materials, the particle size range of the electromagnetic response-enhancing particulate material is 100~500 mesh, and after surface modification or compounding treatment, the apparent density range in the emulsified asphalt system is 0.9~1.1 g / cm³; the bonding reinforcement component is selected from one or more of styrene-butadiene rubber (SBR) latex, SBS emulsion, silane coupling agent and their composite system, used to improve the bonding performance between the repair material and the crack interface, and improve the dispersion stability of the electromagnetic response-enhancing particulate material in the emulsified asphalt system.

[0032] By adjusting the type, particle size, dosage, and proportion of bonding reinforcement components of the electromagnetic response-enhancing particulate material, the crack repair material can meet the requirements for microwave response performance, crack penetration performance, interfacial bonding performance, and storage stability. Specifically, the heating rate of the crack repair material after microwave heating is not less than 20℃ / min; the dynamic viscosity at 25℃ is not higher than 150 mPa·s; the interfacial adhesion strength with aggregate is not less than 4 MPa; and the storage stability is not higher than 0.1%.

[0033] S2, prepare asphalt mixture crack specimens with different degrees of damage to obtain the initial state of cracks; wherein, a semi-circular bending specimen is used to simulate the crack damage state of asphalt pavement, including: preparing cylindrical asphalt mixture specimens using a rotary compactor and cutting them along the center of the specimen to form a semi-circular bending specimen; applying fatigue load at the notch of the semi-circular bending specimen to cause different degrees of crack damage to the specimen; determining the degree of crack damage by the ratio of the number of pre-fatigue loading times to the fatigue life of the complete specimen, as shown in formula (1).

[0034] (1);

[0035] In the formula, The degree of crack damage, % The number of pre-fatigue loading cycles is [number] times; To determine the fatigue life of the complete specimen, multiple load cycles were performed. The degree of crack damage was controlled within the range of 20% to 90% to obtain crack-damaged specimens under different service conditions.

[0036] S3, the crack area is filled with the repair material and the repair process is activated by microwave heating to achieve active crack repair; the crack repair material is applied to the crack area so that the repair material enters the crack and the repair process is activated by microwave heating; wherein, microwave heating equipment is used to directionally heat the crack area, and by adjusting the microwave power, heating time and heating distance, the crack area reaches the temperature range required for the repair material to soften and flow.

[0037] S4, respectively, acquire the changes in equivalent crack width, fatigue life and dissipated energy before and after repair, and establish a multi-dimensional repair effect evaluation method based on crack morphology restoration, mechanical property restoration and dissipated energy restoration; among them, the crack morphology changes before and after repair are acquired by crack image acquisition and analysis methods, and the crack morphology restoration effect is evaluated by equivalent crack width restoration rate. Among them, crack area images before and after repair are acquired by image acquisition equipment, and crack area contours are extracted by image enhancement, binarization processing and edge recognition methods, and crack area and crack boundary perimeter are calculated; based on the relationship between crack area and crack boundary perimeter, the equivalent crack width index is defined as shown in formula (2).

[0038] (2);

[0039] In the formula, A is the equivalent crack width, in mm; A is the crack area, in mm. 2 ; denoted as the perimeter of the crack boundary, in mm.

[0040] The equivalent crack width recovery rate is calculated based on the change in equivalent crack width before and after repair, as shown in formula (3).

[0041] (3);

[0042] In the formula, The equivalent crack width recovery rate is % The equivalent crack width before repair, in mm; The equivalent crack width after repair, in mm;

[0043] The mechanical property recovery effect of the repaired cracked specimen is evaluated by fatigue loading test, including: testing the fatigue life of the complete specimen, the cracked specimen before repair and the specimen after repair respectively; and calculating the fatigue life recovery rate based on the change in fatigue life, as shown in formula (4).

[0044] (4);

[0045] In the formula, The fatigue life recovery rate is % To determine the fatigue life after repair, one load cycle; The remaining fatigue life before repair, one load cycle; For the complete fatigue life of the specimen, 1 load cycle;

[0046] The change in dissipated energy is calculated by the load-displacement curve during the fatigue loading process, which is used to evaluate the energy recovery capability after crack repair. The dissipated energy of a single loading cycle is calculated according to the area of ​​the load-displacement hysteresis curve, as shown in formula (5).

[0047] (5); in, Indicates load, Indicates unit displacement; This represents the energy dissipated during a single loading cycle.

[0048] The cumulative energy dissipation of the specimen is calculated by summing the energy dissipation of each loading cycle, as shown in formula (6).

[0049] (6);

[0050] The dissipated energy recovery rate is calculated according to the following formula (7).

[0051] (7);

[0052] In the formula, The dissipated energy recovery rate is % J represents the cumulative energy dissipated by the repaired specimen. The cumulative dissipated energy of the crack-damaged specimen is J; J represents the total energy dissipated by the complete specimen.

[0053] A comprehensive evaluation index for repair effect is established based on the equivalent crack width recovery rate, fatigue life recovery rate, and dissipated energy recovery rate to comprehensively evaluate the effect of strong microwave response materials in repairing asphalt pavement cracks. The comprehensive evaluation index for repair effect is calculated according to formula (8).

[0054] (8);

[0055] In the formula, As a comprehensive evaluation index for restoration effectiveness, % The equivalent crack width recovery rate is % The fatigue life recovery rate is % The dissipated energy recovery rate is % , , These are the weighting coefficients corresponding to crack morphology recovery, mechanical property recovery, and dissipated energy recovery, respectively, and satisfy the following conditions: + + =1. The weighting coefficients are determined using the analytic hierarchy process (AHP), expert weighting method, or data analysis method based on the evaluation requirements.

[0056] S5. By analyzing the repair effects under different crack damage degrees and microwave heating conditions, the appropriate timing for crack repair and microwave heating parameters are determined. Specifically, repair experiments are conducted on specimens with different crack damage degrees to obtain comprehensive repair effect evaluation indicators corresponding to different damage states. Based on the variation law of comprehensive repair effect evaluation indicators with crack damage degree, the appropriate repair timing for active crack repair using strong microwave responsive materials is determined.

[0057] By setting up crack repair experiments under different microwave output power, heating time and radiation distance conditions, the comprehensive repair effect evaluation index corresponding to different microwave heating parameters was obtained; the correlation between the comprehensive repair effect evaluation index and microwave heating parameters was established, and the microwave heating parameters applicable to different crack repair conditions were determined according to the principle of maximizing the comprehensive repair effect evaluation index.

[0058] Example 1:

[0059] This invention provides a method for evaluating the repair effect of asphalt pavement cracks based on strong microwave response materials, comprising the following steps:

[0060] (1) Emulsified asphalt was selected as the base material, graphite powder as the microwave-responsive reinforcing material, and SBR latex as the binding reinforcing component to prepare a crack repair material with microwave response, crack penetration, and interfacial adhesion properties. The graphite powder had a particle size range of 150–200 mesh and an apparent density of 0.95 g / cm³ in the emulsified asphalt system. By optimizing the ratio of the microwave-responsive reinforcing material to the binding reinforcing component, the repair material exhibited good electromagnetic response performance, storage stability, and interfacial adhesion properties. Tests showed that the crack repair material achieved a heating rate of 30℃ / min, a dynamic viscosity of 110 mPa·s at 25℃, an interfacial adhesion strength with aggregates of 4.5 MPa, and a storage stability of 0.07%.

[0061] (2) Rotary compaction specimens were prepared using SMA-13 ​​asphalt mixture commonly used in highway pavements. Figure 2 As shown, cylindrical specimens with a diameter of 150 mm and a height of 180 mm were first prepared using a rotary compactor. Then, semi-circular bending (SCB) specimens were cut along the center of the specimen. Uniaxial loading tests were conducted on the SCB specimens using a universal testing machine to determine the failure load. Based on this, fatigue loading tests were carried out at different stress ratios to analyze the fatigue performance of the specimens under different stress levels. and The variation law was studied. The results showed that when the stress ratio was 0.25, the fatigue life of the specimen was moderate and the dispersion of fatigue failure was small. Therefore, a stress ratio of 0.25 was selected as the subsequent crack damage construction condition.

[0062] (3) Based on the fatigue loading conditions determined above, pre-fatigue loading was applied to the SCB specimens, and specimens with different damage degrees were obtained by controlling the number of pre-fatigue loading cycles. In this embodiment, specimens with different damage degrees ( Cracks were collected in specimens with crack areas of 50%, 60%, 70%, and 80%, and images of the cracks before repair were acquired using a high-resolution scanning device. The crack region contour was extracted using image processing methods, and the equivalent crack width was calculated based on the crack region area and crack boundary length. ), as an initial state evaluation parameter for crack morphology. In addition, the remaining fatigue life of the specimen after pre-damage ( ) and residual dissipated energy ( (To be tested)

[0063] (4) such as Figure 3 As shown, the prepared crack repair material is applied to the crack area of ​​the SCB specimen after pre-fatigue damage, allowing the repair material to penetrate into the crack. Subsequently, a microwave heating device is used to directionally heat the crack area. Through the absorption of microwave energy by the strong microwave responsive material, a thermal effect is generated, achieving active repair of the crack area. In this embodiment, the initial temperature is 25℃, the microwave power is 2kW, the heating time is 60s, the heating distance is 20mm, and the average temperature of the crack area after heating is 85℃.

[0064] (5) After the repair is completed, test the equivalent crack width of the healed specimen ( ), cumulative fatigue life of the repaired specimen ( ), cumulative energy dissipation of the repaired specimen ( And calculate the equivalent crack width recovery rate according to formulas (3), (4), and (7) respectively. ), fatigue life recovery rate ( ), dissipated energy recovery rate ( According to formula (8), since there are three evaluation indicators, namely equivalent crack width recovery rate, fatigue life recovery rate, and dissipated energy recovery rate, the values ​​of the three weighting coefficients are determined according to the principle of equal proportion. , , All values ​​are taken as 1 / 3, and the comprehensive restoration effect evaluation index is calculated ( As shown in Table 1, when the pre-fatigue damage level is 70%, Since the maximum value is reached, a damage level of approximately 70% is determined as the appropriate crack repair window under the material conditions.

[0065] Table 1. Influence of pre-fatigue degree on crack healing effect

[0066] ;

[0067] (6) Further repair experiments were conducted under different microwave heating temperature conditions to analyze the repair temperature ( The impact of this material on the comprehensive repair effect evaluation index is shown in Table 2. Based on the variation law of the comprehensive repair effect evaluation index under different heating temperatures, 90℃ was determined to be the suitable repair temperature for this material.

[0068] Table 2. Influence of Repair Temperature on Evaluation Indicators of Comprehensive Crack Repair Effectiveness

[0069] ;

[0070] Further establish the relationship between the final temperature of the crack area and the microwave power, heating time, and heating distance (as shown in formula (9)). Through this relationship, the microwave heating parameters can be deduced from the target repair temperature. For example, keeping the heating power at 2kW and the heating distance at 20mm constant, and adjusting the heating time to 65s, can make the microwave heating parameters... It is 90℃.

[0071] (9);

[0072] In the formula, The final temperature of the crack region is given in °C. t is the initial temperature (°C); P is the microwave power (kW); t is the heating time (s); d is the heating distance (mm).

[0073] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for evaluating the repair effect of asphalt pavement cracks based on strong microwave response materials, characterized in that, Includes the following steps: S1. Prepare or provide crack repair materials with strong microwave response performance, crack penetration performance and interfacial bonding performance; S2. Prepare asphalt mixture crack specimens with different degrees of damage to obtain initial state information before crack repair; S3. The crack area is filled with repair material and the repair process is activated by microwave heating to achieve active crack repair. S4. Obtain the characteristics of crack morphology changes, fatigue life changes, and dissipated energy changes before and after repair, and establish a multi-dimensional repair effect evaluation method based on crack morphology recovery, mechanical property recovery, and dissipated energy recovery. Among them, crack morphology recovery characterizes the filling and closing effect of the repair material on the geometric contour of the crack; mechanical property recovery characterizes the recovery effect of the crack area's resistance to fatigue load after repair; and dissipated energy recovery characterizes the recovery effect of the energy dissipation characteristics of the crack area during fatigue damage after repair. S5. By analyzing the differences in the multi-dimensional repair effect evaluation results under different crack damage degrees and different microwave heating conditions, the appropriate crack repair timing and microwave heating parameters are determined.

2. The method for evaluating the repair effect of asphalt pavement cracks based on strong microwave response materials according to claim 1, characterized in that, In step S1, the crack repair material includes emulsified asphalt, electromagnetically responsive reinforced particulate material, and bonding reinforcement component; The electromagnetic response-enhancing particle material is selected from one or more of iron-based and carbon-based microwave absorbing materials; the bonding reinforcement component is selected from one or more of styrene-butadiene rubber latex, SBS emulsion, silane coupling agent and their composite system, which are used to improve the bonding performance between the repair material and the crack interface and improve the dispersion stability of the electromagnetic response-enhancing particle material in the emulsified asphalt system.

3. The method for evaluating the repair effect of asphalt pavement cracks based on strong microwave response materials according to claim 2, characterized in that, In step S1, by adjusting the type, particle size and dosage of electromagnetic response-enhancing particulate material and the proportion of bonding reinforcement components, the crack repair material can meet the preset requirements for microwave response performance, crack penetration performance, interfacial bonding performance and storage stability.

4. The method for evaluating the repair effect of asphalt pavement cracks based on strong microwave response materials according to claim 1, characterized in that, In step S2, a semi-circular bending specimen is used to simulate the crack damage state of asphalt pavement. The semi-circular bending specimen is formed by cutting a cylindrical asphalt mixture specimen along the center position, and fatigue load is applied to the notch position of the semi-circular bending specimen for a preset number of times to cause different degrees of crack damage to the specimen. The degree of crack damage is determined by the ratio of the number of pre-fatigue loading cycles to the fatigue life of the intact specimen.

5. The method for evaluating the repair effect of asphalt pavement cracks based on strong microwave response materials according to claim 1, characterized in that, In step S3, the crack repair material is applied to the crack area and penetrates into the crack. A microwave heating device is used to directionally heat the crack area. By adjusting the microwave power, heating time, and heating distance, the crack area reaches the temperature range required for the repair material to soften and flow.

6. The method for evaluating the repair effect of asphalt pavement cracks based on strong microwave response materials according to claim 1, characterized in that, In step S4, images of the crack area before and after repair are collected, and the contour of the crack area is extracted through image enhancement, binarization processing and edge recognition. The equivalent crack width is determined based on the crack area and the perimeter of the crack boundary, and the degree of crack morphology restoration is determined based on the change of the equivalent crack width before and after repair.

7. The method for evaluating the repair effect of asphalt pavement cracks based on strong microwave response materials according to claim 1, characterized in that, In step S4, fatigue life is obtained by conducting fatigue loading tests on the cracked specimens before and after repair. The degree of mechanical property recovery is determined based on the relationship between the remaining fatigue life of the cracked specimen before repair, the fatigue life of the specimen after repair, and the fatigue life of the intact specimen.

8. The method for evaluating the repair effect of asphalt pavement cracks based on strong microwave response materials according to claim 1, characterized in that, In step S4, the dissipated energy of each loading cycle is determined by the load-displacement curve during the fatigue loading process. The cumulative dissipated energy of the specimen is determined based on the sum of the dissipated energy of each loading cycle. The degree of dissipated energy recovery is determined based on the relationship between the cumulative dissipated energy of the cracked specimen before repair, the cumulative dissipated energy of the specimen after repair, and the cumulative dissipated energy of the intact specimen.

9. The method for evaluating the repair effect of asphalt pavement cracks based on strong microwave response materials according to claim 8, characterized in that, A comprehensive evaluation index for repair effect is constructed based on the degree of crack morphology recovery, mechanical property recovery, and dissipated energy recovery. By assigning corresponding weight coefficients to each degree of recovery and performing weighted summation, the effect of strong microwave response material in repairing asphalt pavement cracks is comprehensively evaluated. The weight coefficients are determined according to the evaluation requirements using the analytic hierarchy process, expert weighting method, or data analysis method.

10. The method for evaluating the repair effect of asphalt pavement cracks based on strong microwave response materials according to claim 9, characterized in that, In step S5, repair tests are conducted on specimens with different degrees of crack damage to obtain the comprehensive repair effect evaluation index corresponding to each damage state. Based on the change law of the comprehensive repair effect evaluation index with the degree of crack damage, the appropriate repair time for active crack repair using strong microwave response material is determined.

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