Comprehensive evaluation system and method for performance of crack pouring adhesive of asphalt pavement in seasonal frozen region

Abstract

The invention belongs to the technical field of highway engineering materials, and discloses a comprehensive evaluation system and method for the performance of a crack pouring adhesive of an asphalt pavement in a seasonal frozen region. Through short-term and long-term aging tests, evaluation indexes such as a penetration ratio, a compression elastic recovery rate and low-temperature stretching are added, and an entropy weight-TOPSIS combination method is adopted, so that the performance of the crack pouring adhesive of the asphalt pavement in the seasonal frozen region is comprehensively evaluated. And constructing an index evaluation model suitable for the working performance of the asphalt pavement crack pouring adhesive in the seasonal frozen region. The test result shows that the control standards of the penetration ratio and the compression elasticity recovery rate after short-term aging are respectively 90% and 30%, and the control standards of the penetration ratio and the compression elasticity recovery rate after long-term aging are respectively 50% and 20%. By adopting the entropy weight-TOPSIS method, whether the sample is qualified or not can be judged, and the advantages and disadvantages of the sample can be comprehensively judged according to the evaluation result of each index. Research results are helpful for improving the application effect and durability evaluation level of the crack pouring material, and supplement and reference data are provided for performance evaluation and standard revision of the crack pouring adhesive in the cold region.

Description

Technical Field

[0001] The invention belongs to the technical field of highway engineering materials, and in particular relates to a system and method for comprehensively evaluating the performance of crack sealing glue for asphalt pavement in seasonally frozen areas. Background Art

[0002] Asphalt pavement fatigue cracking is the most common disease phenomenon of cold-region highways. Under the repeated action of driving loads, cracks develop and intensify, which in turn affects the service life of the highway. At present, heated caulking glue is often used to repair pavement cracks at home and abroad, and the effect is obvious. However, the evaluation standards and specifications of various countries and regions are significantly regional. Among them, developed countries such as the United States have formulated testing specifications for heated pavement crack sealants. The Ministry of Transport of China issued the industry standard for heated pavement caulking glue (JT / T-740) in 2009 and revised it in 2015. This specification was an important basis for domestic pavement heated caulking glue at that time, but there were certain defects in the implementation process, especially in the northern seasonal freezing area, the low-temperature performance of heated caulking glue was seriously insufficient, and under the strong freeze-thaw cycle, the waterproof performance of the pavement was greatly reduced, which seriously affected the caulking effect. It can be seen that which indicators are used to accurately evaluate the working performance of caulking glue is an important basis for affecting the long-term use effect of caulking glue in seasonal freezing areas. The quality evaluation of heated caulking adhesive has been studied. Some scholars have proposed to evaluate the quality of caulking adhesive by bending beam rheometer (BBR) and dynamic shear rheometer (DSR) tests, creep stiffness, m-value and temperature sensitivity weighted normalized value, and use glass transition temperature and dynamic stiffness modulus to predict the low temperature performance of caulking adhesive and evaluate its compatibility in specific environments. Some scholars have also proposed to use the Brookfield rotational viscometer with an improved SC4-27 spindle to test viscosity and improve the thickness of BBR specimens to evaluate the low temperature performance of caulking adhesive. Based on the research of Al-Qadi's team, Sawalha proposed an improved test method based on DTT. Its advantage is that it can evaluate the bonding performance of caulking adhesive after temperature aging, and proposed a performance-based selection guide for road caulking adhesive in North America. Yang et al. set a performance-based low temperature selection threshold to verify that the laboratory selection threshold has a good correlation with the site. Li et al. obtained the tensile-stress relaxation equation by testing heated caulking adhesive and silicone sealant, and proposed to evaluate the low temperature performance of caulking adhesive by stress relaxation index. The above studies all used laboratory conditions to simulate the on-site low-temperature tensile conditions of the caulking glue, but in actual use, the caulking glue will also be affected by the seasonal freeze-thaw cycle and damaged. Although Wang et al. designed a freeze-thaw cycle test device to simulate the change process of the caulking glue during the freeze-thaw cycle, the test process did not consider the aging problem of the caulking glue process. The aging of the heated caulking glue seriously affects the working performance of the caulking glue. Masson et al. found that the heating kettle and heating spray gun during construction would cause the caulking glue to age, resulting in a decrease in its working performance. Some scholars have proposed to put the caulking glue into the reactor for 4 hours to react in order to fully simulate the short-term aging during the construction process.Li et al. used oven heating to simulate the long-term aging of caulking adhesive and found that both long-term and short-term aging would affect the performance of caulking adhesive. However, the current domestic standards do not have clear requirements for the aging of caulking adhesive.

[0003] The technical problems brought about by existing technologies in industrial applications mainly include the following aspects:

[0004] 1) The evaluation index is single and cannot fully evaluate the performance of the caulking glue

[0005] The current industry standards for pavement heating caulking glue (such as China's JT / T-740 standard) use relatively simple evaluation indicators, mainly focusing on the determination of basic physical properties, and lacking comprehensive performance evaluation of caulking glue under complex environmental conditions. This single indicator evaluation system is difficult to fully reflect the actual performance of caulking glue in cold areas, especially seasonal freezing areas, resulting in poor selection and application of caulking glue.

[0006] 2) Ignoring the impact of special climatic conditions in cold regions

[0007] In the process of formulating the current standards, the special climatic conditions in cold regions were not fully considered, especially the stringent requirements on the performance of caulking adhesives under the frequent freeze-thaw cycles in seasonally frozen areas. Due to the complex and changeable environmental conditions in seasonally frozen areas, the elasticity and crack resistance of traditional caulking adhesives at low temperatures are insufficient, and they cannot adapt to the changes in material stress caused by freeze-thaw cycles, which greatly reduces the repair effect.

[0008] 3) Ignoring the effects of aging

[0009] The current evaluation system does not pay enough attention to the aging effect of caulking adhesive, especially the lack of systematic research on the aging behavior of caulking adhesive in short-term aging and long-term use in actual construction. Caulking adhesive is prone to thermal oxidation aging during heating construction, and will be further aged by environmental factors in long-term use, resulting in performance degradation. The current specifications lack clear requirements and evaluation methods for these aging effects, and cannot effectively predict and guarantee the long-term performance of caulking adhesive.

[0010] 4) Laboratory simulation is out of touch with actual application

[0011] Although existing studies simulate the low-temperature performance and tensile behavior of caulking adhesives under laboratory conditions, they often ignore the impact of on-site construction and long-term environmental exposure. This disconnect between the laboratory and actual application means that the performance of caulking adhesives often fails to achieve the expected results in actual projects, affecting the durability and service life of the road surface.

[0012] The main technical problems faced by existing technologies in industrial applications include imperfect evaluation systems, neglect of special environmental conditions in cold regions, lack of systematic research on aging effects, and disconnection between laboratory evaluation and practical application. These problems have led to unsatisfactory application effects of caulking glue in cold-region road maintenance, increased maintenance costs, and shortened road service life. New technical solutions are urgently needed to improve and optimize the performance evaluation and application methods of caulking glue. Summary of the invention

[0013] In view of the problems existing in the prior art, the present invention provides a system and method for comprehensively evaluating the performance of asphalt pavement joint sealant in seasonally frozen areas.

[0014] The present invention is achieved in that a comprehensive determination method for the performance of asphalt pavement crack filling glue in seasonally frozen areas comprises:

[0015] Step 1: Through short-term and long-term aging tests, it is proposed to add cone penetration ratio, compression elastic recovery rate, and low-temperature tensile evaluation indicators;

[0016] Step 2: The entropy weight-TOPSIS combination method is used to construct an index evaluation model suitable for the working performance of asphalt pavement joint sealing glue in seasonally frozen areas.

[0017] Further, the calculation of the cone penetration ratio is:

[0018]

[0019] Where, Kp is the ratio of cone penetration of the residue after heating the sample, %; P1 is the cone penetration of the sample before heating (0.1mm), mm; P2 is the cone penetration of the sample after heating, mm;

[0020] The difference in softening points is used as an evaluation index to judge the aging performance of the caulking glue and calculated:

[0021] ΔT=T2-T1 (2)

[0022] Formula, ΔT is the change in the softening point of the sample after heating, ℃; T1 is the softening point of the sample before heating aging, ℃; T2 is the softening point of the sample after heating aging, ℃.

[0023] Furthermore, the compression elastic recovery rate is:

[0024] The compression elastic recovery rate after short-term aging is used as the main indicator, and the ratio of the compression elastic recovery rate before and after aging is used as the indicator after long-term aging:

[0025]

[0026] Where Kr is the ratio of the residual compressive elastic recovery rate of the sample after heating, r1 is the compressive elastic recovery rate after long-term aging, P+100–F, and r2 is the compressive elastic recovery rate after short-term aging, %.

[0027] Furthermore, the low temperature tensile evaluation index is:

[0028] Since the tensile force of the caulking glue plays a major role in the low-temperature stretching process, the short-term aging minimum tensile stress index at -30℃ and -20℃ is used as the evaluation basis for the low-temperature tensile performance, and the calculation is:

[0029]

[0030] Where, δnt is the maximum tensile stress at the t-th cycle, MPa; t is the third cycle or the number of cycles when failure occurs; Ft is the maximum tensile force at the t-th cycle, kN; A is the force-bearing area, mm2;

[0031] Therefore, the short-term aging minimum tensile stress at -30℃ and -20℃ should be determined by equation (5). If both are satisfied, the larger the better.

[0032]

[0033] Furthermore, the entropy weight-TOPSIS combination method includes: an entropy weight method and a TOPSIS method.

[0034] Furthermore, the entropy weight method:

[0035] (1) Normalized decision matrix

[0036]

[0037] Among them, A1, A2, ..., An are alternatives; C1, C2, ..., Cm are index items, and xij is the score of Ai according to index Ci; its benefit index can be normalized by (7), and its cost index can be standardized by (8);

[0038]

[0039] Among them, max xij is the maximum value of the alternative value of j, and min xij is the minimum value of the alternative value of j;

[0040] (2) Calculate the contribution of the i-th solution to the j-th index;

[0041]

[0042] In the formula, pij represents the contribution index of the i-th alternative with j index;

[0043] (3) Calculate the entropy value eij of the j-th index;

[0044]

[0045] In the formula, the constant k is generally taken as k = 1 / ln n, which can ensure that 0 <eij<1;

[0046] (4) The coefficient of each indicator weight is determined by the following formula:

[0047]

[0048] g j =1-e j (12)

[0049] Among them, gj indicates that the contribution of each scheme to the j index is inconsistent and is determined by;

[0050] TOPSIS method:

[0051] The application of TOPSIS should follow the following steps: multiply the corresponding weights by matrix B to obtain the weighted normalized decision matrix B as shown in (13).

[0052]

[0053] The positive ideal solution Aj+ and the negative ideal solution Aj- are determined as follows:

[0054]

[0055] Define the maximum distance between the positive ideal solution and the negative ideal solution,

[0056]

[0057] Calculate the relative closeness of the positive ideal solution to each alternative,

[0058]

[0059] Another object of the present invention is to provide a comprehensive evaluation system for the performance of asphalt pavement crack filling glue in seasonally frozen areas, comprising:

[0060] The test module is used to propose additional evaluation indicators such as cone penetration ratio, compression elastic recovery rate, and low-temperature tensile strength through short-term and long-term aging tests;

[0061] The construction module is used to construct an index evaluation model for the working performance of asphalt pavement joint filling glue in seasonally frozen areas by adopting the entropy weight-TOPSIS combination method.

[0062] Another object of the present invention is to provide a computer device, which includes a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the method for comprehensively measuring the performance of asphalt pavement caulking glue in seasonally frozen areas.

[0063] Another object of the present invention is to provide a computer-readable storage medium storing a computer program, which, when executed by a processor, enables the processor to execute the steps of the method for comprehensively measuring the performance of asphalt pavement caulking glue in seasonally frozen areas.

[0064] Another object of the present invention is to provide an information data processing terminal, which is used to implement the comprehensive evaluation system for the performance of asphalt pavement caulking glue in seasonally frozen areas.

[0065] In combination with the above technical solutions and the technical problems solved, please analyze the advantages and positive effects of the technical solutions to be protected by the present invention from the following aspects:

[0066] First, additional indicators such as cone penetration ratio, compression elastic recovery rate and low-temperature tensile strength have been added to more comprehensively reflect the actual use of caulking glue in seasonally frozen areas.

[0067] The entropy weight-TOPSIS combined method was adopted, which can not only judge the qualification of the caulking glue samples, but also comprehensively evaluate their advantages and disadvantages.

[0068] Through short-term and long-term aging tests, the present invention proposes to add evaluation indicators such as cone penetration ratio, compression elastic recovery rate, and low-temperature stretching, and adopts the entropy weight-TOPSIS combination method to construct an index evaluation model suitable for the working performance of asphalt pavement joint sealant in seasonally frozen areas. The test results show that: ① The control standards of cone penetration ratio and compression elastic recovery rate after short-term aging are 90% and 30% respectively, and the control standards of cone penetration ratio and compression elastic recovery rate after long-term aging are 50% and 20% respectively. ② The evaluation standard of joint sealant viscosity is 1-3Pa·s at 190℃, the evaluation standard of injection depth is 5cm, the evaluation standard of low-temperature tensile stress of joint sealant after immersion in water is 0.06Mpa (-30℃) and 0.03Mpa (-20℃), and the evaluation standard of joint sealant adhesion after freeze-thaw cycle is 0.03Mpa (-30℃) and 0.025Mpa (-20℃). ③ The entropy weight-TOPSIS method can not only determine whether the sample is qualified or not, but also comprehensively judge the quality of the sample according to the evaluation results of each indicator. The research results are helpful to improve the application effect and durability evaluation level of caulking materials, and provide supplementary and reference data for the performance evaluation and specification revision of caulking glue in cold regions.

[0069] Second, the expected benefits and commercial value of the technical solution of the present invention after transformation are as follows: The technical solution of the present invention has broad market prospects in the application of cold seasonal freezing areas. Due to the strong demand for asphalt crack repair on roads in seasonal freezing areas, and the inability of existing caulking glue materials and evaluation systems to meet the high standards in cold environments, the comprehensive evaluation system proposed by the present invention can accurately evaluate the performance of caulking glue, thereby promoting the development and application of high-performance caulking glue products. Expected benefits include:

[0070] The technical solution of the present invention fills the technical gap in the industry at home and abroad: the comprehensive determination method of the performance of asphalt pavement joint sealant in seasonally frozen areas proposed by the present invention, especially in terms of the addition of evaluation indicators and the application of the entropy weight-TOPSIS combination method, fills the gap in the prior art for the comprehensive evaluation of joint sealant performance under cold climate conditions. The prior art lacks a systematic and comprehensive evaluation of the long-term and short-term performance of joint sealants in low temperature and freeze-thaw environments. The present invention is aimed at this technical difficulty and proposes a complete solution, thereby creating a new research and application direction in related fields at home and abroad.

[0071] Whether the technical solution of the present invention overcomes technical bias: In the process of formulating the technical solution, the present invention overcomes the bias of traditional evaluation methods that only focus on a single indicator, and adopts a multi-indicator comprehensive evaluation method to more objectively and fairly reflect the actual performance of the caulking glue. At the same time, the application of the entropy weight-TOPSIS combination method also avoids the subjectivity and limitations brought by the single weight evaluation method, embodies the scientific and reasonable decision-making logic, and breaks the long-standing technical bias in the evaluation of caulking materials.

[0072] Third. The present invention solves several key problems in the prior art in industrial applications through parameter setting, algorithm design and application of mathematical models, and has achieved significant technological progress:

[0073] 1) Existing technical problems: The performance evaluation indicators of caulking glue are insufficient, and it is difficult to fully reflect the actual performance of the material.

[0074] The performance evaluation of traditional caulking adhesives usually relies on a few indicators and cannot fully reflect the performance of the material under complex climatic conditions. Especially in extreme environmental areas such as seasonal freezing zones, the existing evaluation system is not perfect.

[0075] The present invention introduces multiple key parameters, including cone penetration ratio, compression elastic recovery rate and low-temperature tensile performance, which are obtained through short-term and long-term aging tests and can comprehensively evaluate the adaptability and long-term performance of caulking glue in seasonally frozen areas. These new parameters make up for the shortcomings of traditional evaluation indicators, making the performance evaluation of caulking glue more comprehensive and accurate.

[0076] 2) Problems with existing technologies: Traditional evaluation methods are highly subjective and lack scientific weight allocation and comprehensive analysis.

[0077] In the performance evaluation of caulking glue, the importance of different indicators is often difficult to quantify objectively, resulting in highly subjective evaluation results and inconsistent results between different evaluators, which affects the reliability of the evaluation.

[0078] The present invention adopts an evaluation model combining the entropy weight method and the TOPSIS method. The entropy weight method objectively determines the weight of each indicator by calculating the entropy value of each evaluation indicator, thereby eliminating the interference of subjective factors. On this basis, the TOPSIS rule scientifically performs comprehensive sorting by calculating the proximity of each caulking glue scheme to the ideal solution. This combined algorithm effectively improves the objectivity and consistency of the evaluation results, making the evaluation process more scientific and reliable.

[0079] 3) Problems with existing technologies: Mathematical models lack systematicity and are difficult to apply in complex environments

[0080] Traditional evaluation models are usually designed for specific indicators or specific scenarios, lack systematicity, and cannot conduct effective performance evaluation under complex environmental conditions (such as seasonally frozen areas).

[0081] The present invention constructs a systematic mathematical model through the entropy weight-TOPSIS combination method, which can comprehensively consider multiple performance indicators and transform the complex multi-index evaluation into a simple and operable comprehensive scoring system through normalization processing and ideal solution analysis. This mathematical model is not only applicable to asphalt pavement joint sealants in seasonally frozen areas, but can also be extended to material evaluation in other complex environments according to actual application requirements, and has strong versatility and application value.

[0082] 4) Problems with existing technologies: Material aging evaluation is single and it is difficult to predict long-term performance changes

[0083] Existing aging evaluation methods for caulking glue materials mostly focus on a single aging indicator and are unable to accurately predict performance changes of the material during long-term use, resulting in the risk of material failure during use.

[0084] The present invention proposes a systematic aging performance evaluation method by comprehensively analyzing the compression elastic recovery rate ratio and softening point change of short-term and long-term aging. Combined with the weight coefficient determined by the entropy weight method, this method can accurately predict the performance changes of caulking glue during long-term use, providing a scientific basis for the durability evaluation of caulking materials and significantly reducing the failure risk of materials during use.

[0085] The present invention successfully solves many deficiencies in the prior art through parameter optimization, algorithm innovation and systematic construction of mathematical models, significantly improves the accuracy and reliability of performance evaluation of caulking glue materials in complex environments such as seasonal freezing zones, provides strong technical support for material selection and application, and has broad industrial application prospects.

[0086] Fourth, the technical solution of the present invention solves the key problems in the prior art in industrial applications and has achieved significant technical progress:

[0087] 1) Existing technical problems: Lack of performance evaluation method for caulking glue that is suitable for the special climatic conditions in seasonal freezing areas

[0088] When the caulking glue of asphalt pavement in seasonally frozen areas undergoes seasonal freeze-thaw cycles, its performance is easily affected by severe cold and sudden temperature changes, which makes it difficult for traditional caulking glue evaluation indicators to fully and accurately reflect the actual working performance of the material. In this case, the existing evaluation methods often cannot effectively guide the selection and application of caulking glue.

[0089] Through short-term and long-term aging tests, the present invention proposes new evaluation indicators such as cone penetration ratio, compression elastic recovery rate and low-temperature tensile strength, which can better reflect the actual working performance of the caulking glue in seasonally frozen areas. In particular, the low-temperature tensile performance of the material is analyzed in a targeted manner, making the evaluation method more comprehensive and accurate, and providing a scientific basis for the selection of caulking glue for asphalt pavements in seasonally frozen areas.

[0090] 2) Problems of existing technology: Subjectivity and uncertainty in the evaluation of caulking glue performance

[0091] Traditional methods for evaluating the performance of caulking glue often rely on experience and judgment and lack scientific quantitative analysis, which leads to highly subjective evaluation results and poor consistency between different evaluators, affecting the reliability of the evaluation and the promotion of its application.

[0092] The present invention adopts the entropy weight-TOPSIS combination method to construct a comprehensive performance evaluation model for asphalt pavement joint sealant in seasonally frozen areas. The entropy weight method objectively reflects the importance of different evaluation indicators by calculating the weights of each indicator and eliminates subjectivity; the TOPSIS rule quantifies the pros and cons of each solution by calculating the relative proximity of the positive ideal solution and the negative ideal solution. This combination method enhances the scientificity and objectivity of the evaluation and significantly improves the accuracy and consistency of the evaluation results.

[0093] 3) Problems of existing technology: The evaluation index is single and it is difficult to fully reflect the performance of the caulking glue

[0094] Existing evaluation methods usually only focus on a single indicator (such as softening point, cone penetration, etc.), but ignore the comprehensive performance of the material among multiple properties, and are unable to comprehensively evaluate the durability and reliability of caulking adhesives under complex climatic conditions.

[0095] The present invention introduces multiple indicators into the evaluation method, including cone penetration ratio, compression elastic recovery rate and low-temperature tensile performance. Through the comprehensive analysis of these indicators, the working performance of the caulking glue in the seasonal freezing area can be comprehensively evaluated. This method not only takes into account the short-term performance of the material, but also fully evaluates the aging characteristics in long-term use, providing a more comprehensive evaluation system to ensure the long-term stability of the caulking glue in practical applications.

[0096] 4) Problems with existing technologies: The evaluation model lacks systematicity and is difficult to apply to actual projects.

[0097] Traditional caulking glue performance evaluation methods often lack systematic model support. Problems such as improper selection of indicators and arbitrary weight setting are prone to occur during the evaluation process, resulting in poor actual application of the model and difficulty in extending it to different engineering scenarios.

[0098] The present invention constructs a systematic evaluation model, objectively determines the weight of each indicator through the entropy weight method, and comprehensively ranks the performance of each caulking glue in combination with the TOPSIS method, forming a scientific, rigorous and systematic evaluation method. This model is not only applicable to seasonal freezing areas, but can also be expanded and adjusted according to actual needs to adapt to the specific needs of different projects, and has a high promotion value.

[0099] In summary, the present invention successfully solves many problems existing in the prior art through an innovative evaluation method, significantly improves the performance evaluation accuracy and scientificity of asphalt pavement joint sealant in seasonally frozen areas, and provides strong technical support for the selection and application of joint sealants. This progress not only improves the quality of the project, but also reduces maintenance costs, and has broad industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0100] Figure 1 It is a flow chart of a method for comprehensively determining the performance of crack sealing glue for asphalt pavement in seasonally frozen areas provided by an embodiment of the present invention.

[0101] Figure 2 It is a structural block diagram of a comprehensive evaluation system for the performance of asphalt pavement crack sealing glue in seasonally frozen areas provided by an embodiment of the present invention.

[0102] Figure 3 The basic test items provided in the embodiments of the present invention are (A) cone penetration test; (B) softening point test; (C) compression elastic recovery test; (D) fluidity test; (E) UTM-100 universal testing machine; (F) low temperature tensile fixture diagram.

[0103] Figure 4 It is a technical flow chart of this research provided by an embodiment of the present invention.

[0104] Figure 5 This is a caulking glue depth test process provided by an embodiment of the present invention: (a) hamburger rutting specimen (b) gap simulation (c) pouring caulking glue (d) caulking depth measurement diagram.

[0105] Figure 6 1. The present invention provides a crack caulking glue sample test (A) Brookfield viscometer (B) Hamburger rutting specimen (C) immersion test (D) freeze-thaw cycle test diagram.

[0106] Figure 7 The present invention provides a test sample cone penetration aging process and comparative analysis (a) aging process curve (b) sample comparison diagram.

[0107] Figure 8 It is a comparison diagram of the softening point of the test sample before and after aging provided by the embodiment of the present invention.

[0108] Fig. 9 This is a comparison chart of the compression elastic recovery rate of the caulking glue before and after aging provided by an embodiment of the present invention.

[0109] Fig.10 It is a curve diagram of the relationship between the tensile force and displacement of each caulking glue sample provided in an embodiment of the present invention.

[0110] Fig.11 It is a viscosity-temperature curve diagram of the caulking glue sample provided in an embodiment of the present invention.

[0111] Fig.12 It is a diagram of the injection depth of each caulking glue sample provided in an embodiment of the present invention.

[0112] Fig.13 It is a curve diagram of the relationship between the tension and displacement of the caulking glue after immersion in water and stretching provided by an embodiment of the present invention.

[0113] Fig.14 This is a low-temperature water immersion stretching diagram provided by an embodiment of the present invention.

[0114] Fig.15 It is a curve diagram of the relationship between the tension and displacement of each caulking glue under the action of freeze-thaw cycle provided by an embodiment of the present invention.

[0115] Fig.16 It is a destruction diagram of sample H provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0116] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0117] like Figure 1 As shown, a method for comprehensively measuring the performance of asphalt pavement crack filling glue in seasonally frozen areas provided by an embodiment of the present invention comprises the following steps:

[0118] S101, through short-term and long-term aging tests, proposes to add cone penetration ratio, compression elastic recovery rate, and low-temperature tensile evaluation indicators;

[0119] S102, using the entropy weight-TOPSIS combination method, constructs an index evaluation model for the working performance of asphalt pavement joint sealant in seasonally frozen areas.

[0120] The comprehensive determination method of the performance of asphalt pavement joint sealant in seasonally frozen areas first simulates the impact of climate conditions in seasonally frozen areas on asphalt joint sealant through short-term and long-term aging tests. The short-term aging test mainly focuses on the influence of factors such as temperature and ultraviolet rays on the joint sealant when it is exposed to the environment in the early stage of construction, while the long-term aging test simulates the aging of the material caused by climate and temperature changes during long-term use. Through these tests, the changes in the mechanical properties of the joint sealant are determined, and the key factors affecting its performance are screened out.

[0121] Based on the test results, three evaluation indicators were added to the method: cone penetration ratio, compression elastic recovery rate and low-temperature tensile. The cone penetration ratio reflects the hardness of the material and its stability under temperature changes; the compression elastic recovery rate measures the ability of the material to return to its original state after compression deformation, and can evaluate its compression and deformation resistance; the low-temperature tensile index mainly examines the flexibility and crack resistance of the caulking glue in a low-temperature environment, which is particularly important for coping with the frequent low-temperature environment in seasonal freezing areas.

[0122] In order to comprehensively evaluate the various properties of caulking glue, the entropy weight method was used to determine the weight of each evaluation index. The entropy weight method objectively allocates the weight of each evaluation index based on the change in the amount of information in the data distribution to avoid the influence of subjective judgment. The weight allocation of each indicator not only depends on its respective importance, but also takes into account the performance of different caulking glues in the test, ensuring the reasonable reflection of each indicator in the model.

[0123] Finally, the TOPSIS method is used to comprehensively rank the working performance of different caulking glues. The TOPSIS method determines the relative advantages and disadvantages of each caulking glue by calculating the distance between it and the ideal solution and the negative ideal solution. This multi-index-based evaluation model can accurately identify the caulking glue with the best performance in the working environment of the seasonal freezing zone, thus providing a scientific basis for the actual engineering selection.

[0124] The calculation of the cone penetration ratio provided in the embodiment of the present invention is:

[0125]

[0126] Where, Kp is the ratio of cone penetration of the residue after heating the sample, %; P1 is the cone penetration of the sample before heating (0.1mm), mm; P2 is the cone penetration of the sample after heating, mm;

[0127] The difference in softening points is used as an evaluation index to judge the aging performance of the caulking glue and calculated:

[0128] ΔT=T2-T1 (2)

[0129] Formula, ΔT is the change in the softening point of the sample after heating, ℃; T1 is the softening point of the sample before heating aging, ℃; T2 is the softening point of the sample after heating aging, ℃.

[0130] The compression elastic recovery rate provided by the embodiment of the present invention is:

[0131] The compression elastic recovery rate after short-term aging is used as the main indicator, and the ratio of the compression elastic recovery rate before and after aging is used as the indicator after long-term aging:

[0132]

[0133] Where Kr is the ratio of the residual compressive elastic recovery rate of the sample after heating, r1 is the compressive elastic recovery rate after long-term aging, P+100–F, and r2 is the compressive elastic recovery rate after short-term aging, %.

[0134] The low temperature tensile evaluation index provided by the embodiment of the present invention is:

[0135] Since the tensile force of the caulking glue plays a major role in the low-temperature stretching process, the short-term aging minimum tensile stress index at -30℃ and -20℃ is used as the evaluation basis for the low-temperature tensile performance, and the calculation is:

[0136]

[0137] Where, δnt is the maximum tensile stress at the t-th cycle, MPa; t is the third cycle or the number of cycles when failure occurs; Ft is the maximum tensile force at the t-th cycle, kN; A is the force-bearing area, mm2;

[0138] Therefore, the short-term aging minimum tensile stress at -30℃ and -20℃ should be determined by equation (5). If both are satisfied, the larger the better.

[0139]

[0140] The entropy weight-TOPSIS combination method provided by the embodiment of the present invention includes: an entropy weight method and a TOPSIS method.

[0141] The entropy weight method provided by the embodiment of the present invention is as follows:

[0142] (1) Normalized decision matrix

[0143]

[0144] Among them, A1, A2, ..., An are alternatives; C1, C2, ..., Cm are index items, and xij is the score of Ai according to index Ci; its benefit index can be normalized by (7), and its cost index can be standardized by (8);

[0145]

[0146] Among them, max xij is the maximum value of the alternative value of j, and min xij is the minimum value of the alternative value of j;

[0147] (2) Calculate the contribution of the i-th solution to the j-th index;

[0148]

[0149] In the formula, pij represents the contribution index of the i-th alternative with j index;

[0150] (3) Calculate the entropy value eij of the j-th index;

[0151]

[0152] In the formula, the constant k is generally taken as k = 1 / ln n, which can ensure that 0 <eij<1;

[0153] (4) The coefficient of each indicator weight is determined by the following formula:

[0154]

[0155] g j =1-e j (12)

[0156] Among them, gj indicates that the contribution of each scheme to the j index is inconsistent and is determined by;

[0157] TOPSIS method:

[0158] The application of TOPSIS should follow the following steps: multiply the corresponding weights by matrix B to obtain the weighted normalized decision matrix B as shown in (13).

[0159]

[0160] The positive ideal solution Aj+ and the negative ideal solution Aj- are determined as follows:

[0161]

[0162] Define the maximum distance between the positive ideal solution and the negative ideal solution,

[0163]

[0164] Calculate the relative closeness of the positive ideal solution to each alternative,

[0165]

[0166] like Figure 2 As shown, a comprehensive evaluation system for the performance of asphalt pavement joint sealant in seasonally frozen areas provided by an embodiment of the present invention includes:

[0167] The test module is used to propose additional evaluation indicators such as cone penetration ratio, compression elastic recovery rate, and low-temperature tensile strength through short-term and long-term aging tests;

[0168] The construction module is used to construct an index evaluation model for the working performance of asphalt pavement joint filling glue in seasonally frozen areas by adopting the entropy weight-TOPSIS combination method.

[0169] Another object of the present invention is to provide a computer device, which includes a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the method for comprehensively measuring the performance of asphalt pavement caulking glue in seasonally frozen areas.

[0170] Another object of the present invention is to provide a computer-readable storage medium storing a computer program, which, when executed by a processor, enables the processor to execute the steps of the method for comprehensively measuring the performance of asphalt pavement caulking glue in seasonally frozen areas.

[0171] Another object of the present invention is to provide an information data processing terminal, which is used to implement the comprehensive evaluation system for the performance of asphalt pavement caulking glue in seasonally frozen areas.

[0172] The present invention is specifically implemented:

[0173] 1 Materials and experimental design

[0174] 1.1 Test materials

[0175] The test selected eight types of caulking glue commonly used for asphalt pavement maintenance in the Northeast seasonal freezing area, and classified them according to "Pavement Heating Sealant" JT / T 740, 4 types are suitable for -20℃, and 4 types are suitable for -30℃. Among them, the test temperature used for the caulking glue is tested according to the recommended temperature when purchasing, and the basic parameters of the caulking glue are shown in Table 1.

[0176] Table 1 Basic parameters of heating type caulking glue

[0177]

[0178]

[0179] 1.2 Experimental design

[0180] 1.2.1 Basic Experiment

[0181] The eight types of caulking glue used in the experiment were tested for cone penetration, softening point, compression elastic recovery rate, fluidity and low-temperature tensile properties. Figure 3 As shown. Among them, the cone penetration can reflect the ability of the caulking adhesive to resist the embedding of foreign matter, the softening point is the key evaluation index of the high temperature performance of the caulking adhesive, the compression elastic recovery rate can indirectly reflect the deformation recovery ability of the caulking adhesive under vehicle load and low temperature and the flexibility under low temperature conditions, the fluidity reflects the stability of the caulking adhesive under high temperature, and the low temperature tensile property includes tensile strength and cross-sectional adhesion, which is used to evaluate the low temperature working performance of the caulking adhesive. The basic test process is as follows Figure 4 shown.

[0182] 1.2.2 Performance test of caulking glue

[0183] (1) Construction process simulation

[0184] When the caulking glue is applied on site, the caulking machine needs to be heated to 190°C, and each can of caulking glue takes about 2 to 4 hours to use. Due to the long heating time during the construction process, the caulking glue is very prone to aging. For short-term aging tests, the indoor simulated aging temperature can be determined based on the caulking glue construction temperature, that is, 190°C. The aging time can be determined based on the caulking glue construction time, that is, 4 hours. In indoor tests, the caulking glue can be placed in an oven and kept warm at 190°C for 4 hours to simulate the construction process.

[0185] (2) Viscosity test

[0186] During on-site construction, the caulking glue is heated and injected into the cracks through the caulking machine spray gun, and quickly infiltrates and cools. Its micropore penetration capacity is mainly determined by viscosity. Since low-viscosity caulking glue has strong permeability and good bonding performance, high-viscosity caulking glue has poor spraying speed and poor bonding effect. Although high temperature can reduce viscosity, it accelerates the aging of caulking glue. Therefore, this test uses a Brookfield viscometer to measure the viscosity of caulking glue. Keep the rotor and sample cylinder in an oven for 1.5 hours, and keep the caulking glue in a constant temperature container for 15 minutes. Use a 27dPa·s rotor to ensure that the torque reading is within the range of 10% to 98%. When the reading is stable, determine the measured value of the sample.

[0187] (3) Filling depth test

[0188] Two hamburger rutting specimens (320mm×260mm×50mm) were assembled, and a proper amount of dust powder was placed at the joint of the two specimens. Then each sample was placed vertically with the two parts 15mm apart to simulate the crack width of the actual road surface, and the caulking glue was slowly injected into the cracks and maintained for 2 hours. Subsequently, the two specimens bonded together with the caulking glue were restored to two pieces along the bonding crack position, and five positions were selected at the bonding interface to record the penetration depth of the caulking glue to determine the caulking glue injection depth value. The test process is as follows: Figure 5 shown.

[0189] (4) Water immersion stability test

[0190] Due to the abundant snowfall in seasonally frozen areas in winter, a large amount of melted snow and rainwater will penetrate into the road surface and roadbed. In view of this, according to the relevant requirements of ASTM D5329 and D6690, the caulking glue samples were immersed in 25℃ water for 96 hours and subjected to three sets of cyclic tensile tests, and the adhesion of the test samples during the stretching process was tested.

[0191] (5) Freeze-thaw cycle test

[0192] The freeze-thaw cycle in seasonally frozen areas has a significant impact on the mechanical properties of asphalt mixtures and modified asphalt binders. This test reference and specification uses interlayer specimens for heat treatment and cold treatment

[39] . For heat treatment, the interlayer specimens are placed in a 60°C oven for no less than 4 hours, and a compression test is performed under the action of their own weight. Then, the heat treatment is completed after cooling at room temperature for 6 hours. For cold treatment, -15°C is selected for the test. The heat-treated specimens are placed in a -15°C environmental chamber for no less than 4 hours and stretched using a UTM testing machine at a stretching rate of 1.5 mm / min to 150% of the casting width (i.e., 22.5 mm). Then a 22.5 mm stretching positioning block is placed between the substrates so that the sealant can maintain the stretching amplitude, and a freeze-thaw cycle is completed after being placed at room temperature for 6 hours. According to this method, three freeze-thaw cycle tests are carried out, and the tensile value of the specimens after the freeze-thaw cycle is tested.

[0193] (6) Long-term aging test

[0194] The current specifications mainly consider the compression elastic recovery rate and cone penetration value in the initial use, and do not consider the performance and recovery ability of the caulking glue after long-term use. In this test, the caulking glue samples are prepared and placed in a 60℃ ventilated oven for 7 days to simulate the aging of the caulking glue after long-term work. After the aging of the caulking glue is completed, the test is carried out after cooling at 25℃±5℃ for 1 hour.

[0195] 2. Analysis of test results

[0196] 2.1 Analysis of basic index test results

[0197] The test samples are tested for cone penetration, softening point and other indicators, such as Figure 6 The test results are shown in Table 2 and Table 3. According to the test results of basic indicators, the change curves of different indicators of the test samples before and after aging are drawn, as shown in Figure 7 to Figure 9 shown.

[0198] Table 2-30℃ sample performance test results

[0199]

[0200] Table 3-20℃ sample performance test results

[0201]

[0202] (1) Cone penetration analysis

[0203] like Figure 7As shown in the figure, after short-term aging, the cone penetration of six caulking glue samples decreased significantly. After long-term aging, the cone penetration of all eight caulking glue samples decreased significantly. It can be seen that long-term aging has the most significant effect on the change of cone penetration of caulking glue. Considering that road caulking glue is essentially a sealant, the cone penetration ratio is introduced as an evaluation index of the thermal aging performance of caulking glue with reference to ASTM D2872

[40] . The calculation of the cone penetration ratio is shown in Formula 1.

[0204]

[0205] Wherein, Kp is the ratio of cone penetration of the residue after heating the sample, %; P1 is the cone penetration of the sample before heating (0.1mm), mm; P2 is the cone penetration of the sample after heating, mm.

[0206] The cone penetration ratio after short-term aging can reflect the short-term anti-aging performance of the caulking glue, and the cone penetration ratio after long-term aging can reflect the long-term use performance of the caulking glue. According to the cone penetration ratio after short-term aging of 90%, the short-term aging resistance of ≥90% is good, and test samples A, C, D, E, F, and G all belong to this category. Less than 90% has poor short-term aging resistance, and samples B and H belong to this category. When considering the cone penetration ratio after long-term aging, 50% is used as the boundary value. ≥50% has good long-term aging resistance, and test samples B, C, D, F, G, and H all belong to this category. <50% has poor long-term aging resistance, and samples A and E belong to this category. Comprehensive observation shows that there is no obvious correlation between good short-term aging performance and long-term aging performance. The reason is related to the different contents of modifiers, softeners and other modifiers mixed in different products.

[0207] (2) Softening point analysis

[0208] The softening points of the caulking glue samples obtained in the test before and after aging were compared. Figure 8 As shown in the figure, the change in softening point is very obvious. Among them, the softening points of four caulking glue samples A, B, E, and F decreased significantly with short-term aging, the softening points of three caulking glue samples C, G, and H increased, and the softening points of one caulking glue sample D remained unchanged.

[0209] Referring to ASTM D2872, the difference in softening points is used as an evaluation index for judging the aging performance of caulking glue, and the calculation is shown in Formula 2.

[0210] ΔT=T2-T1 (2)

[0211] Formula, ΔT is the change in the softening point of the sample after heating, ℃; T1 is the softening point of the sample before heating aging, ℃; T2 is the softening point of the sample after heating aging, ℃.

[0212] According to the change in the softening point difference after short-term aging, the caulking glue is divided into two categories with 3°C as the boundary. A, B, and G with a softening point greater than 3°C after aging belong to the type with poor aging performance, and C, D, E, F, and H with a softening point less than 3°C belong to the type with good aging performance.

[0213] (3) Compression elastic recovery rate analysis

[0214] The compression elastic recovery rate of each caulking glue sample was tested after three stages of unaging, short-term aging and long-term aging, and a curve was plotted to reflect the changing pattern of the compression elastic recovery rate of the caulking glue with the aging process.

[0215] like Fig. 9 As shown in Figure 3, the compression elastic recovery rate of the caulking glue will be affected to a certain extent after each aging. In general, the compression elastic recovery rate decreases sharply with the increase of aging time. Considering that the caulking glue will experience short-term aging during the construction process, the compression elastic recovery rate after short-term aging is used as the main indicator, and the ratio of the compression elastic recovery rate before and after aging is used as the indicator after long-term aging, as shown in Formula 3.

[0216]

[0217] Where Kr is the ratio of the residual compressive elastic recovery rate of the sample after heating, r1 is the compressive elastic recovery rate after long-term aging, P+100–F, and r2 is the compressive elastic recovery rate after short-term aging, %.

[0218] According to the compression elastic recovery rate after short-term aging, it is recommended that the compression elastic recovery rate after short-term aging should be ≥30%. According to the compression elastic recovery rate after long-term aging, it is recommended that the compression elastic recovery rate after long-term aging should be ≥20%. According to the ratio of compression elastic recovery rate after long-term aging, it can be divided into two categories. The ratio of compression elastic recovery rate after long-term aging is ≥80%: B, C, E, F. These caulking adhesives have good long-term aging resistance. The ratio of compression elastic recovery rate after long-term aging is <80% A, D, G, H. These caulking adhesives have poor long-term aging resistance. The test results are shown in Table 4.

[0219] Table 4 Cone penetration ratio, softening point difference and compression elastic recovery ratio of caulking glue test samples

[0220]

[0221]

[0222] Regarding the above-mentioned long-term and short-term aging phenomena, the main commercial components of heated caulking glue on the market are asphalt, rubber powder, SBS, softener, expander, filler, etc., and the aging rules of different caulking glues are not completely consistent. The main reason is that different caulking glues have differences in storage time, component ratio, admixture composition, etc. The short-term aging insulation temperature is too high and the heating time is too long. There is volatilization of light oil and degradation of waste rubber powder in the process. The volatilization of oil will cause the cone penetration to decrease and the softening point to increase. The degradation of rubber powder will cause the cone penetration of the caulking glue to increase and the softening point to decrease. During long-term aging, the volatilization of oil, the degradation of rubber powder and polymer are also the main reasons for the decrease in the compression elastic recovery rate of the caulking glue.

[0223] (4) Liquidity analysis

[0224] The fluidity after aging reflects whether the caulking glue will flow at high temperatures during service. As shown in Table 5, the fluidity of the caulking glue samples after aging has decreased. Although the fluidity before and after aging meets the maximum fluidity requirement of 5mm in the current specification, with the large-scale use of SBS and rubber powder in road caulking glue, SBS, rubber and added fillers will significantly improve the high-temperature performance of asphalt, and future products should meet the fluidity requirements. Therefore, it is recommended to reduce the fluidity requirements.

[0225] Table 5 Fluidity of each sample before and after aging

[0226]

[0227] (5) Low temperature tensile analysis

[0228] The caulking glue sample was subjected to three cyclic tensile tests, and the maximum tensile stress value at the end of the stretching was detected. The test results are shown in Table 6, and the relationship curve between tensile force and displacement is shown in Figure 8 shown.

[0229] Table 6 Maximum tensile strength at low temperature

[0230]

[0231] like Fig.10As shown in the figure, none of the samples was damaged during the stretching process. When three cycles were performed, the first one reflected the initial tension, and the third one reflected the tension at the end of the cycle. For the caulking glue that was not subjected to short-term aging, the maximum tension decreased as the number of cycles increased. It can be seen that low-temperature cycles have a significant effect on the mechanical properties of the caulking glue. In the early stage of stretching, the displacement of the caulking glue samples showed a linear growth trend, with obvious elastic characteristics. As the stretching continued, the displacement continued to grow, but the tension fluctuated, indicating that the asphalt had a certain degree of stress relaxation

[41] . The caulking glue after aging has lower tension and maximum tension than that before aging. It can be seen that the aging of the caulking glue has a significant effect on the attenuation of tension. In addition, the curves of some caulking glues D and H after aging have changed significantly compared with those without aging. This shows that short-term aging has an impact on the caulking glue in the initial stage and the entire evolution stage. It is also related to the degradation of rubber powder in the caulking glue during the aging process and the volatilization or aging of other modifiers.

[0232] Since the tensile force of the caulking adhesive plays a major role in the low-temperature tensile process, the short-term aging minimum tensile stress index at -30℃ and -20℃ is used as the evaluation basis for the low-temperature tensile performance, and the calculation is shown in Formula 4.

[0233]

[0234] Where, δnt is the maximum tensile stress at the t-th cycle, MPa; t is the third cycle or the number of cycles when failure occurs; Ft is the maximum tensile force at the t-th cycle, kN; A is the force-bearing area, mm2.

[0235] Therefore, the short-term aging minimum tensile stress at -30℃ and -20℃ should be determined by equation (5). If both are satisfied, the larger the better.

[0236]

[0237] 2.2 Analysis of test results of new indicators

[0238] (1) Viscosity analysis

[0239] The viscosity of eight kinds of caulking glue at different temperatures is plotted into a scatter plot, such as Fig.11As shown. The viscosity of each caulking glue decreases with the increase of temperature. Among them, the early viscosity of -30℃ caulking glue is higher than that of -20℃ caulking glue, mainly because more rubber powder and other fillers are added during production to meet the low temperature performance. At 180℃, the viscosity of -30℃ caulking glue drops sharply and gradually approaches the viscosity of -20℃ caulking glue. The reason is that as the temperature rises, the softener in -30℃ caulking glue begins to melt, increasing its fluidity and thus enhancing the overall fluidity of the caulking glue. At 190℃, the viscosity of -30℃ caulking glue and -20℃ caulking glue are both in the range of 1 to 3Pa·s. At 200℃, the viscosity of -30℃ caulking glue and -20℃ caulking glue is relatively low. It can be seen that short-term high temperature aging has a significant effect on the viscosity of caulking glue.

[0240] The viscosity of the caulking glue at 190°C is considered to be between 1 and 3 Pa·s as a reference standard. If it is not within this range, the performance of the caulking glue is considered to be poor and will not be used.

[0241] (2) Injection depth analysis

[0242] The caulking glue test sample is tested for its grouting depth, such as Fig.12 As shown. Comparing the overall penetration depth of -30℃ caulking glue and -20℃ caulking glue, among the -30℃ caulking glue samples, the penetration depth of sample C is the largest. Among the -20℃ caulking glue samples, the penetration depth of sample E is the largest. The reason is that the additives such as softeners contained in it cause its high-temperature fluidity to be larger and the cooling rate to be slower. Moreover, during the test, no obvious difference was found in the penetration depth of the two caulking glues with different applicable temperatures after the caulking glue was cooled. Therefore, the penetration depth of 5cm is used as the discrimination value of the evaluation index. According to the test situation, it is considered to select a penetration depth ≥5cm as the penetration depth indicator, and <5cm is not considered to be adopted.

[0243] (3) Water immersion stability analysis

[0244] After the caulking glue samples were immersed in water, a low-temperature tensile test was carried out. The maximum tensile force of the caulking glue after immersion in water is shown in Table 7. According to the test results, the relationship curves between the tensile force and displacement of each caulking glue sample after immersion in water are plotted as shown in Table 7. Fig.13 shown.

[0245] Table 7 Maximum tensile force of caulking glue after immersion in water

[0246]

[0247] like Fig.13 As shown in the figure, it shows obvious elastic characteristics in the early stage of stretching. The tensile force shows a significant increasing trend with the increase of displacement. Fig.10The results of low-temperature tensile testing after aging show that the low-temperature tensile properties after immersion in water have changed to a certain extent. The maximum tensile force and the tensile force during the tensile change process are higher than the values ​​after aging. The main reason is that water penetrates into the caulking glue through the gaps in the asphalt mixture, increasing the adhesion between the interface in the asphalt mixture and the caulking glue itself [35-37]. The tensile force of samples B and F dropped sharply during the third set of cyclic stretching. This is because the water in samples B and F evaporated during the placement process, causing some ice crystals to break during the stretching process, which in turn caused a decrease in tensile force. In view of this, the minimum tensile stress during low-temperature stretching, that is, the minimum tensile stress in formula (5), can be used as a caulking glue identification indicator. The changes in the samples before and after immersion in water are as follows: Fig.14 shown.

[0248] (4) Analysis of freeze-thaw cycle test results

[0249] The eight kinds of caulking glue samples were subjected to freeze-thaw cycle tests, and the maximum tensile force after freeze-thaw cycles was tested, as shown in Table 8. After freeze-thaw cycles, the tensile force and displacement curves of the caulking glue are as shown in Table 8. Fig.15 As shown in the test results, it can be seen that the tensile change curves of the -30℃ and -20℃ caulking adhesives that have undergone freeze-thaw cycles are quite different from those that have not undergone freeze-thaw cycles. Fig.15 As shown in the figure, with the increase of the number of freeze-thaw cycles, the tension shows a significant linear growth trend with the increase of displacement. It can be seen that the increase in the number of freeze-thaw cycles causes the SBS inside the caulking glue and the spatial network structure formed by the rubber powder in it to be destroyed, which in turn causes its tension to change. After the freeze-thaw cycle, the maximum tension of the caulking glue is significantly reduced, and the tension gradually decreases with the increase of the number of cycles. Among them, when sample H undergoes the third freeze-thaw cycle, the tension-displacement curve is significantly different from the first and second cycles. It can be seen from the appearance damage of sample H that Fig.16 As shown, the reason is due to bonding failure.

[0250] Table 8 Maximum tensile force of freeze-thaw cycle

[0251]

[0252] In view of this, the minimum tensile force after freeze-thaw cycles is used as a new evaluation index. For -30℃ caulking glue, 0.03MPa is used as the discrimination value, and for -20℃ caulking glue, 0.025MPa is used as the discrimination value. If it is satisfied, the larger the better.

[0253] 3 Evaluation index system

[0254] 3.1 Evaluation indicators

[0255] For the comprehensive evaluation of caulking glue indicators, many appropriate evaluation methods can be used. Li, Zhou, et al.

[32] proposed an evaluation index for caulking glue by comprehensively sorting out performance evaluation indicators, thermal stability of heated caulking glue, and stability after immersion. There are many mature evaluation methods in other fields, such as principal component analysis [33, 34] TOPSIS evaluation method [35, 36], fuzzy comprehensive determination method

[37] , etc. Hwang and Yoon

[38] proposed a method of ranking by comparing the degree of similarity with the ideal solution. In this method, the best option is the one that is closest to the ideal solution and farthest from the negative solution. The weight of each indicator should be determined before evaluation. Entropy weight method is one of the objective weighting methods. Combined with the test results and analysis, it is considered to add indicators such as the cone penetration ratio after long-term and short-term aging, softening point difference, compression elastic recovery rate ratio after long-term aging, compression elastic recovery rate after long-term and short-term aging, low-temperature tensile stress, freeze-thaw cycle tensile stress, injection depth, and 190°C viscosity after meeting the original specifications to construct an evaluation index system for the caulking glue.

[0256] 3.2 Evaluation methods

[0257] 3.2.1 Entropy Weight Method

[0258] (1) Normalized decision matrix

[0259]

[0260] Among them, A1, A2, ..., An are alternatives; C1, C2, ..., Cm are indicator items, and xij is the score of Ai according to indicator Ci. Among them, indicators are generally divided into two categories: cost indicators and benefit indicators. The benefit index means that the higher the indicator, the better, while the cost index is the opposite. The data in the decision matrix D comes from different sources. In order to facilitate comparison, it needs to be normalized into a dimensionless matrix. Its benefit index can be normalized by (7), and its cost index can be standardized by (8).

[0261]

[0262] Among them, max xij is the maximum value of the alternative value of j, and min xij is the minimum value of the alternative value of j.

[0263] (2) Calculate the contribution of the i-th solution to the j-th index.

[0264]

[0265] Where pij represents the contribution index of the i-th alternative with index j.

[0266] (3) Calculate the entropy value eij of the j-th index.

[0267]

[0268] In the formula, the constant k is generally taken as k = 1 / ln n, which can ensure that 0 <eij<1。

[0269] (4) The coefficient of each indicator weight is determined by the following formula.

[0270]

[0271] g j =1-e j (12)

[0272] Among them, gj indicates that the contribution degree of each scheme to the j index is inconsistent and is determined by.

[0273] 3.2.2 TOPSIS method

[0274] The application of TOPSIS should follow the following steps

[45] . Multiply the corresponding weights by the matrix B to obtain the weighted normalized decision matrix B as shown in (13).

[0275]

[0276] The positive ideal solution Aj+ and the negative ideal solution Aj- are determined as follows:

[0277]

[0278]

[0279] Define the maximum distance between the positive ideal solution and the negative ideal solution,

[0280]

[0281] Calculate the relative closeness of the positive ideal solution to each alternative,

[0282]

[0283] Sorting them according to their relative closeness, the best solution has a higher δ i value, which is closer to the positive ideal solution.

[0284] 3.3 Evaluation system construction

[0285] At present, the performance evaluation of heated caulking glue in China is all conducted in accordance with JT / T 740. In the test, as long as the caulking glue meets the requirements for product performance in JT / T 740, the product is considered qualified. This method has certain problems. First, for caulking glue applicable to the same temperature range, the test results are only qualified or unqualified. This test method cannot significantly distinguish the performance of caulking glue; secondly, in the evaluation index system used, the short-term aging, caulking depth, long-term aging of the caulking glue during the caulking process, and the stability and tolerance after freeze-thaw cycles and immersion in water are not considered. This study tested the cone penetration, softening point, fluidity, compression elastic recovery rate and low-temperature tensile properties of the caulking glue according to the JT / T 740 industry standard. At the same time, the short-term aging performance of the caulking glue, the caulking depth during construction, viscosity, long-term aging performance, and the caulking glue performance after immersion and freeze-thaw cycles were tested. Due to the many influencing factors, the entropy weight method was used to determine the entropy weight of each evaluation index. When calculating the weight, the decision matrix of the index was constructed. This study uses the cone penetration ratio after long-term and short-term aging, the difference in softening point, the ratio of compression elastic recovery rate after long-term aging, low-temperature tensile stress, 190℃ viscosity, injection depth, and freeze-thaw cycle tensile stress as evaluation indicators. The weights of each indicator obtained by calculation are shown in Table 9.

[0286] Table 9 Index weights

[0287]

[0288] It can be seen from the data that the weights of the two indicators, compression elastic recovery rate after short-term aging and freeze-thaw cycle tensile stress, are the highest, about 19%, which reflects the importance of the two indicators in evaluating the performance of caulking glue and has a higher reference value for the long-term use of materials. In contrast, the weights of low-temperature tensile stress and short-term aging cone penetration ratio are about 4%, and the weights of the indicators are relatively small. From the test results, it can be seen that the constructed indicator system can fully reflect the performance of caulking glue.

[0289] 3.4 Analysis of evaluation results

[0290] The evaluation results of the evaluation system proposed in this study are compared with the evaluation results of the current evaluation method, as shown in Table 10.

[0291] Table 10 Comparison of evaluation results

[0292]

[0293]

[0294] The positive ideal solution (D+) is the distance between the sample object and the optimal solution, and the negative ideal solution (D-) represents the distance between the sample object and the worst solution. The comprehensive score index is calculated based on the two distance values, reflecting the degree of proximity between the sample object and the optimal solution. As shown in Table 10, sample E has the smallest positive ideal solution distance and the largest negative ideal solution distance. Therefore, it has the highest comprehensive score and is the best performance sample among all sample objects. Sample F has the largest positive ideal solution distance, the smallest negative ideal solution distance, and the lowest comprehensive score index, which is a poor quality sample. The current standard evaluation method can only judge whether the sample is qualified or not, but cannot give the performance of each sample. The entropy weight-TOPSIS evaluation method proposed in this study is used to judge the quality of the test samples. For the ranking under different use temperature conditions, the ranking order of -30℃ caulking glue is D>A>C>B, and the ranking order of -20℃ caulking glue is E>G>H>F. It can be seen that the evaluation system based on entropy weight-TOPSIS has certain advantages.

[0295] 4 Conclusion

[0296] (1) The long-term and short-term aging performance of joint sealants is mainly evaluated by the ratio of cone penetration, softening point difference, and compression elastic recovery rate. The test results show that a larger cone penetration ratio, a smaller softening point difference, and a larger compression elastic recovery rate ratio indicate that the joint sealant has better thermal aging performance. According to the test results, the cone penetration ratio, softening point difference, and other indicators were classified and graded. For short-term aging, the cone penetration ratio is 90% as the limit value, and for long-term aging, the cone penetration ratio is 50% as the limit value. The compression elastic recovery rate after short-term aging should be no less than 30%, and the compression elastic recovery rate after long-term aging is 20% as the limit value. These are the most suitable evaluation indicators for evaluating the working performance of joint sealants for asphalt pavements in seasonally frozen areas.

[0297] (2) The experimental test results of the caulking glue samples show that the injection viscosity and injection depth of the heated caulking glue are also important factors that cannot be ignored. The test results show that when evaluating the viscosity of the caulking glue, 1-3 Pa·s at 190℃ should be used as the control index, and the injection depth should be no less than 5cm. The low-temperature tensile index of the caulking glue after immersion in water should be controlled at δmin(-30℃)≥0.06Mpa and δmin(-20℃)≥0.03Mpa, and the adhesion of the caulking glue after freeze-thaw cycles should be controlled at δmin(-30℃)≥0.03Mpa and δmin(-20℃)≥0.025Mpa.

[0298] (3) The entropy weight-TOPSIS method was used to construct a new evaluation system for the performance of asphalt pavement joint sealants in seasonally frozen areas, and the weights of the newly added evaluation indicators and the evaluation indicators used were calculated based on the test results. By evaluating the joint sealant samples at -30℃ and -20℃ and comparing the evaluation results with the evaluation results of the current specifications, the entropy weight-TOPSIS method can not only determine whether the samples are qualified, but also comprehensively judge the quality of the samples based on the evaluation results of each indicator. The evaluation results show that the overall performance of sample D at -30℃ is the best, and the overall performance of sample E at -20℃ is the best. The entropy weight-TOPSIS evaluation system can be used to more comprehensively evaluate the performance of the heating type joint sealant, among which the long-term and short-term performance evaluation is an effective supplement to the current specifications.

[0299] The caulking glue at -30℃ was tested.

[0300] (1) Determine whether the basic performance meets the requirements of JT / T-740

[0301] The cone penetration was 93.4 mm, the softening point was 81.1°C, the fluidity was 2 mm, the compression elastic recovery rate was 57.5%, and it passed three cycles at low temperature.

[0302] (2) After the construction process simulation (short-term aging simulation), the cone penetration softening point, fluidity, compression elastic recovery rate, and low-temperature tensile stress were tested. The softening point after short-term aging was measured to be 81.1°C, the cone penetration was 82.8mm after short-term aging, and 62.7mm after long-term aging. The cone penetration ratio after short-term aging was calculated to be 88.6%, and after long-term aging was 67.2%. The compression elastic recovery rate after short-term aging was 43.3%, and the compression elastic recovery rate after long-term aging was 51.01%. Test the viscosity and injection depth.

[0303] (3) The cyclic tensile force before and after aging measured by low-temperature tensile test was 759N and 606N before aging, and 499N and 275N after aging.

[0304] (4) After the caulking glue was immersed in water, the low-temperature tensile test showed that the three cycle forces were 1181N, 708N, and 375N respectively.

[0305] (5) After the freeze-thaw cycle of the caulking glue, the three cycle forces are 167N, 151N, and 148N respectively.

[0306] (6) Rank the performance of caulking glue based on the entropy weight-TOPSIS method.

[0307] Test the sealant at -20℃

[0308] (1) Based on JT / T-740, its basic performance was determined to be 84.2 mm, the softening point was 81.7°C, the fluidity was 0.5 mm, the compression elasticity recovery rate was 35.4, and it passed three cycles at low temperature.

[0309] (2) After the construction process simulation (short-term aging simulation), the cone penetration softening point, fluidity, compression elastic recovery rate, and low-temperature tensile stress were tested. The softening point after short-term aging was measured to be 84.6°C, the cone penetration was 83.2mm after short-term aging, and 63.2mm after long-term aging. The calculated cone penetration ratio after short-term aging was 98.8%, and after long-term aging was 75.0%. The compression elastic recovery rate after short-term aging was 31.6%, and the compression elastic recovery rate after long-term aging was 24.1%. Test the viscosity and injection depth.

[0310] (3) The cyclic tensile force before and after aging was 560N and 301N before aging, and 307N and 287N after aging.

[0311] (4) After the caulking glue was immersed in water, the low-temperature tensile test results of the three cycles were 324N, 304N, and 297N respectively.

[0312] (5) After freeze-thaw cycles, the three cycle forces of the caulking glue are 309N, 239N, and 221N respectively.

[0313] (6) Rank the performance of caulking glue based on the entropy weight-TOPSIS method.

[0314] The following are two embodiments of the present invention in industrial applications:

[0315] Example 1: Asphalt pavement crack repair project on highways in seasonally frozen areas

[0316] On a highway in a northeastern province, cracks frequently appear on asphalt pavements due to cold weather and large temperature differences, especially during the winter freezing season, when the cracks are further aggravated. To solve the crack problem, the local transportation department decided to use caulking glue to repair the cracks. To ensure the repair effect, the project introduced the comprehensive determination method of the performance of caulking glue for asphalt pavements in freezing zones of the present invention.

[0317] 1. Material selection: Among the various caulking glues provided by material suppliers, the entropy weight-TOPSIS combined evaluation model is used to analyze multiple indicators such as aging test, cone penetration ratio, compression elastic recovery rate and low-temperature tensile performance of the present invention to obtain the caulking glue that is most suitable for the local seasonal freezing environment.

[0318] 2. Performance verification: Based on the test results, the supplier of the best caulking glue was determined, and on-site verification was carried out before construction to ensure that the caulking glue can maintain good tensile properties in low temperature environments, has a high compression elastic recovery rate, and adapts to the special climatic environment of seasonal freezing areas.

[0319] 3. Repair effect: After a period of application monitoring, the cracks on the repaired highway did not show any obvious expansion or damage, proving that the caulking glue selected through this comprehensive measurement method has good adaptability and durability, thereby improving the service life of the road.

[0320] Example 2: Municipal road winter maintenance project

[0321] Municipal roads in a northern city are often affected by freeze-thaw cycles in winter, which leads to aggravated road cracks, affecting driving safety and road service life. The municipal engineering department uses the caulking glue performance determination method of the present invention to screen the most suitable caulking glue material for road crack repair before and after winter.

[0322] 1. Material testing and evaluation: The municipal department purchased a variety of commonly used caulking glues on the market, and conducted short-term and long-term aging tests respectively. The performance of these caulking glues was measured through indicators such as cone penetration ratio, compression elastic recovery rate and low-temperature tensile performance. The entropy weight method was used to determine the weight of each indicator, and the TOPSIS method was used for comprehensive evaluation.

[0323] 2. Optimization selection: The test results show that a certain type of caulking glue exhibits excellent tensile strength under low temperature conditions, and has a high compression elastic recovery rate after long-term aging. The municipal engineering department selected this material for urban road crack repair based on the comprehensive score of the evaluation model.

[0324] 3. Actual application effect: The repaired road maintained good integrity throughout the winter, with no obvious crack expansion or caulking material falling off, and the road surface remained stable after the spring thaw. The successful application of this project provides an important technical reference for winter road maintenance in municipal departments and reduces maintenance costs.

[0325] These two embodiments demonstrate the practical application of the present invention in asphalt pavement repair projects under different climatic conditions, effectively improving the durability and adaptability of road crack repair.

[0326] It should be noted that the embodiments of the present invention can be implemented by hardware, software, or a combination of software and hardware. The hardware part can be implemented using dedicated logic; the software part can be stored in a memory and executed by an appropriate instruction execution system, such as a microprocessor or dedicated design hardware. It can be understood by a person of ordinary skill in the art that the above-mentioned devices and methods can be implemented using computer executable instructions and / or contained in a processor control code, such as a carrier medium such as a disk, CD or DVD-ROM, a programmable memory such as a read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. Such code is provided on the carrier medium. The device and its modules of the present invention can be implemented by hardware circuits such as very large-scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, etc., or programmable hardware devices such as field programmable gate arrays, programmable logic devices, etc., can also be implemented by software executed by various types of processors, and can also be implemented by a combination of the above-mentioned hardware circuits and software, such as firmware.

[0327] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. A comprehensive determination method for the performance of asphalt pavement joint sealant in seasonally frozen areas, characterized in that: The following steps are involved: Step 1: Through short-term and long-term aging tests, it is proposed to add cone penetration ratio, compression elastic recovery rate, and low-temperature tensile evaluation indicators; Step 2: The entropy weight-TOPSIS combination method is used to construct an index evaluation model suitable for the working performance of asphalt pavement joint sealing glue in seasonally frozen areas.

2. The method for comprehensive determination of performance of asphalt pavement joint sealant in seasonally frozen areas as claimed in claim 1, characterized in that: Calculation of the cone penetration ratio: Where, Kp is the ratio of cone penetration of the residue after heating the sample, %; P1 is the cone penetration of the sample before heating (0.1mm), mm; P2 is the cone penetration of the sample after heating, mm; The difference in softening points is used as an evaluation index to judge the aging performance of the caulking glue and calculated: ΔT=T2-T1 (2) Formula, ΔT is the change in the softening point of the sample after heating, ℃; T1 is the softening point of the sample before heating aging, ℃; T2 is the softening point of the sample after heating aging, ℃.

3. The comprehensive determination method for the performance of asphalt pavement sealant in seasonally frozen areas as claimed in claim 1 is characterized in that: The compression elastic recovery rate: The compression elastic recovery rate after short-term aging is used as the main indicator, and the ratio of the compression elastic recovery rate before and after aging is used as the indicator after long-term aging: Where Kr is the ratio of the residual compressive elastic recovery rate of the sample after heating, r1 is the compressive elastic recovery rate after long-term aging, P+100–F, and r2 is the compressive elastic recovery rate after short-term aging, %.

4. The comprehensive determination method for the performance of asphalt pavement sealant in seasonally frozen areas as claimed in claim 1 is characterized in that: The low temperature tensile evaluation index: Since the tensile force of the caulking glue plays a major role in the low-temperature stretching process, the short-term aging minimum tensile stress index at -30℃ and -20℃ is used as the evaluation basis for the low-temperature tensile performance, and the calculation is: Where, δnt is the maximum tensile stress at the tth cycle, MPa; t is the third cycle or the number of cycles when failure occurs; Ft is the maximum tensile force at the tth cycle, kN; A is the force-bearing area, mm2; Therefore, the short-term aging minimum tensile stress at -30℃ and -20℃ should be determined by equation (5). If both are satisfied, the larger the better.

5. The method for comprehensive determination of performance of asphalt pavement joint sealant in seasonally frozen areas as claimed in claim 1, characterized in that: The entropy weight-TOPSIS combination method includes: an entropy weight method and a TOPSIS method.

6. The comprehensive determination method of the performance of asphalt pavement joint sealant in seasonally frozen areas as claimed in claim 5 is characterized in that: The entropy weight method: (1) Normalized decision matrix Among them, A1, A2, ..., An are alternatives; C1, C2, ..., Cm are index items, and xij is the score of Ai according to index Ci; its benefit index can be normalized by (7), and its cost index can be standardized by (8); Among them, max xij is the maximum value of the alternative value of j, and min xij is the minimum value of the alternative value of j; (2) Calculate the contribution of the i-th solution to the j-th index; In the formula, pij represents the contribution index of the i-th alternative with j index; (3) Calculate the entropy value eij of the j-th index; In the formula, the constant k is generally taken as k = 1 / ln n, which can ensure that 0 <eij<1; (4) The coefficient of each indicator weight is determined by the following formula: g j =1-e j (12) Among them, gj indicates that the contribution of each scheme to the j index is inconsistent and is determined by; TOPSIS method: The application of TOPSIS should follow the following steps: multiply the corresponding weights by matrix B to obtain the weighted normalized decision matrix B as shown in (13). The positive ideal solution Aj+ and the negative ideal solution Aj- are determined as follows: Define the maximum distance between the positive ideal solution and the negative ideal solution, Calculate the relative closeness of the positive ideal solution to each alternative, 7. A system for comprehensively evaluating the performance of asphalt pavement joint sealant in seasonally frozen areas, which implements the method for comprehensively determining the performance of asphalt pavement joint sealant in seasonally frozen areas as claimed in any one of claims 1 to 6, characterized in that: The comprehensive evaluation system for the performance of asphalt pavement sealant in seasonally frozen areas includes: The test module is used to propose additional evaluation indicators such as cone penetration ratio, compression elastic recovery rate, and low-temperature tensile strength through short-term and long-term aging tests; The construction module is used to construct an index evaluation model for the working performance of asphalt pavement joint filling glue in seasonally frozen areas by adopting the entropy weight-TOPSIS combination method.

8. A computer device, characterized in that: The computer device includes a memory and a processor, the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the method for comprehensive determination of the performance of asphalt pavement joint sealing glue in seasonally frozen areas as described in any one of claims 1-6.

9. A computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor executes the steps of the method for comprehensively determining the performance of asphalt pavement joint sealant in seasonally frozen areas as described in any one of claims 1 to 6.

10. An information data processing terminal, characterized in that: The information data processing terminal is used to implement the comprehensive evaluation system for the performance of asphalt pavement caulking glue in seasonally frozen areas as described in claim 7.

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