Method for evaluating comprehensive crack resistance of thermosetting epoxy modified asphalt mixture

Abstract

The invention discloses a method for evaluating the comprehensive crack resistance of a thermosetting epoxy modified asphalt mixture, which comprises the following steps: preparing test pieces with different thermosetting epoxy modified asphalt mixing amounts, respectively testing the test pieces at three test temperatures, and recording crack index information in the test process; determining a principal component coefficient of the cracking index information by adopting a principal component analysis method, and constructing principal component vectors which reflect the cracking index information and are mutually independent; solving the variance contribution rates of the principal component vectors, sorting from large to small, and selecting the principal component vectors corresponding to the first two variance contribution rates as evaluation vectors; calculating contribution degrees of different cracking indexes in the evaluation vector, establishing a thermoset epoxy modified asphalt mixture anti-cracking performance evaluation model, and evaluating the anti-cracking performance of the thermoset epoxy modified asphalt mixture. According to the method, a mathematical expression which has definite physical significance and is convenient for engineering application can be formed, and a theoretical basis is provided for anti-cracking design and performance evaluation of the thermosetting epoxy modified asphalt pavement.

Description

Technical Field

[0001] The present invention relates to the field of asphalt mixtures, and in particular to a method for evaluating the comprehensive anti-cracking performance of thermosetting epoxy modified asphalt mixtures. Background Art

[0002] Thermosetting epoxy-modified asphalt mixtures typically consist of base asphalt, aggregate, thermosetting modified resin, and a curing agent. The modification principle is as follows: After incorporating the thermosetting modified resin into the asphalt, it undergoes a cross-linking and hardening reaction with the curing agent, forming a relatively stable three-dimensional network structure between the molecules. Thermosetting modified asphalt offers superior physical and mechanical properties compared to traditional modified asphalt, and is widely used in transportation infrastructure such as steel bridge deck paving, asphalt road surface paving, and airport pavement. Due to the brittleness of thermosetting modified asphalt, traditional asphalt crack resistance evaluation indices may not accurately reflect its crack resistance. Currently, research on thermosetting modified asphalt, both domestically and internationally, has primarily focused on high-temperature stability, rutting resistance, and durability, while research on its crack resistance (particularly low-temperature crack resistance and fatigue crack resistance) remains relatively scarce. Due to a lack of systematic experimental data and theoretical analysis, a universally recognized index system for evaluating the crack resistance of thermosetting modified asphalt has yet to be established. This, to a certain extent, limits the application of this material in cold regions or environments subject to drastic temperature fluctuations. Therefore, in-depth research on the cracking mechanism, crack propagation behavior and influencing factors of thermosetting modified asphalt, and the establishment of a scientific and reasonable evaluation method for crack resistance performance are of great significance for optimizing material design and improving pavement durability. Summary of the Invention

[0003] The present invention provides a method for evaluating the comprehensive anti-cracking performance of thermosetting epoxy modified asphalt mixtures, so as to overcome the technical problem that due to the greater brittleness of thermosetting epoxy modified asphalt materials, traditional asphalt anti-cracking performance evaluation indicators may not accurately reflect their anti-cracking ability. Due to the lack of systematic experimental data and theoretical analysis, a generally recognized indicator system suitable for evaluating the anti-cracking performance of thermosetting epoxy modified asphalt has not yet been formed.

[0004] In order to achieve the above object, the technical solution of the present invention is:

[0005] A method for evaluating the comprehensive anti-cracking performance of a thermosetting epoxy modified asphalt mixture, comprising:

[0006] S1: Prepare specimens for semicircular bending test with different thermosetting epoxy modified asphalt content, test the specimens at three test temperatures, and record the cracking index information of the specimens during the test;

[0007] S2: Use the principal component analysis method to determine the principal component coefficients of the cracking index information of all specimens, and construct a principal component vector that reflects the cracking index information of all specimens and is independent of each other;

[0008] S3: Calculate the variance contribution rate of the principal component vector, sort the variance contribution rates from large to small, and select the principal component vectors corresponding to the first two variance contribution rates as evaluation vectors;

[0009] S4: Calculate the contribution of different cracking indicators in the two evaluation vectors, and establish an evaluation model for the anti-cracking performance of thermosetting epoxy modified asphalt mixture based on the contribution of different cracking indicators in the two evaluation vectors to evaluate the anti-cracking performance of the thermosetting epoxy modified asphalt mixture.

[0010] Furthermore, the cracking index information includes pre-peak fracture energy, post-peak fracture energy, total fracture energy, flexural strength, FI value, crack resistance index and crack initiation index. The expressions of the cracking index information are shown in formula (1):

[0011]

[0012] Where M i-峰前-t 、M i-峰后-t 、M i-总裂-t 、M i-弯拉-t 、M i-FI-t 、M i-抗裂-t and M i-裂萌-t They represent the pre-peak fracture energy, post-peak fracture energy, total fracture energy, flexural strength, FI value, crack resistance index and crack initiation index of the specimen with a thermosetting epoxy modified asphalt content of i% during the test at temperature t; 峰前,i,t 、x 峰后,i,t 、x 总裂,i,t 、x 弯拉,i,t 、x FI,i,t 、x 抗裂,i,t and x 裂萌,i,t They represent the data points corresponding to the cracking index information.

[0013] Furthermore, the principal component analysis method is used to determine the principal component coefficients of the cracking index information of all specimens, and a principal component vector that reflects the cracking index information of all specimens and is independent of each other is constructed, including:

[0014] S21. Standardize all semicircular bending test data using the range standardization method and calculate the correlation matrix of the semicircular bending test data at three test temperatures, as shown in formula (2).

[0015]

[0016] Where R -10 、R 15 and R25 Represents the correlation matrix of semicircular bending test data under three test temperatures; X -10 、X 15 and X 25 Represents the data vector matrix of 7 cracking indicators under three test temperatures; x1 -10 ~x7 -10 、x1 15 ~x7 15 、x1 25 ~x7 25 are the data vectors of seven cracking indices at three test temperatures;

[0017] S22. Solve the principal component coefficient matrix and its covariance matrix in the test data at three test temperatures, as shown in formula (3).

[0018]

[0019] Where A -10 、A 15 and A 25 Represents the principal component coefficient matrix of the cracking index information at three test temperatures; C -10 、C 15 and C 25 They represent the covariance matrices of the cracking index information at three test temperatures; E is the identity matrix; are the principal component coefficients of the seven cracking index information at three test temperatures, are the covariances of the cracking index information at three test temperatures;

[0020] S23, construct the comprehensive principal component coefficient matrix and the principal component vectors of all circular bending test specimens, as shown in formula (4),

[0021]

[0022] Where A c is the comprehensive principal component coefficient matrix; Y1, Y2, Y3, Y4, Y5, Y6 and Y7 represent the principal component vectors of the seven cracking indices, and X1, X2, X3, X4, X5, X6 and X7 represent the pre-peak fracture energy, post-peak fracture energy, total fracture energy, flexural strength, FI value, crack resistance index and crack initiation index, respectively.

[0023] Furthermore, the variance contribution rate of the principal component vector is solved, the variance contribution rates are sorted from large to small, and the principal component vectors corresponding to the first two variance contribution rates are selected as evaluation vectors, including:

[0024] The calculation formula of variance contribution rate is shown in (5).

[0025]

[0026] Where Var(Y1), Var(Y2), Var(Y3), Var(Y4), Var(Y5), Var(Y6) and Var(Y7) represent the variance contribution rates of the seven principal component vectors respectively;

[0027] The variance contribution rates are sorted from large to small, and the principal component vectors corresponding to the first two variance contribution rates are selected as evaluation vectors, which are recorded as PCA1 and PCA2.

[0028] Furthermore, the contribution of different cracking indices in the two evaluation vectors is calculated, and based on the contribution of different cracking indices in the two evaluation vectors, an evaluation model for the crack resistance of thermosetting epoxy modified asphalt mixture is established to evaluate the crack resistance of thermosetting epoxy modified asphalt mixture, including:

[0029] S41. Project the data vectors of the seven cracking indices of all semicircular bending test data at three test temperatures onto PCA1 and PCA2, and calculate the projection value of each index on PCA1 and PCA2, i.e., the contribution, as shown in formula (6):

[0030]

[0031] Wherein, PCA1_contri(Y1), PCA1_contri(Y2), PCA1_contri(Y3), PCA1_contri(Y4), PCA1_contri(Y5), PCA1_contri(Y6) and PCA1_contri(Y7) represent the contribution rates of the seven cracking indices on the PCA1 vector; PCA2_contri(Y1), PCA2_contri(Y2), PCA2_contri(Y3), PCA2_contri(Y4), PCA2_contri(Y5), PCA2_contri(Y6) and PCA2_contri(Y7) represent the contribution rates of the seven cracking indices on the PCA2 vector;

[0032] S42. Calculate PCA1 and PCA2 according to formula (6), as shown in formula (7).

[0033]

[0034] S43. Based on the variance contribution rate of PCA1 and PCA2 and the contribution of cracking index on PCA1 and PCA2, the evaluation model of anti-cracking performance of thermosetting epoxy modified asphalt mixture is constructed, as shown in formula (8).

[0035]

[0036] Among them, CCRI is the comprehensive crack resistance performance, Var1 and Var2 represent the variance contribution rates of vectors PCA1 and PCA2, respectively.

[0037] Beneficial effects: The present invention provides an evaluation method for the comprehensive anti-cracking performance of thermosetting epoxy modified asphalt mixture. Based on the existing cracking indicators, the principal component analysis method is used to reveal the similarities between the indicators, reduce the test dimension of the original data and select the key principal component vectors, and proposes a thermosetting epoxy modified asphalt anti-cracking performance evaluation equation with a concise form and comprehensive information coverage. It can form a mathematical expression with clear physical meaning and convenient engineering application, and provide a theoretical basis for the anti-cracking design and performance evaluation of thermosetting epoxy modified asphalt pavement. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0039] Figure 1 A flow chart of a method for evaluating the comprehensive anti-cracking performance of a thermosetting epoxy modified asphalt mixture provided by the present invention;

[0040] Figure 2 Schematic diagram of performing SCB test and collecting test index information in the present invention;

[0041] Figure 3 The evaluation vector coordinates and the projection diagram of the principal component vector are constructed for the present invention. DETAILED DESCRIPTION

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0043] This embodiment provides a method for evaluating the comprehensive anti-cracking performance of thermosetting epoxy modified asphalt mixture. Figure 1 As shown, including:

[0044] S1: Prepare specimens for semicircular bending test with different thermosetting epoxy modified asphalt content, test the specimens at three test temperatures, and record the cracking index information of the specimens during the test;

[0045] S2: Use the principal component analysis method to determine the principal component coefficients of the cracking index information of all specimens, and construct a principal component vector that reflects the cracking index information of all specimens and is independent of each other;

[0046] S3: Calculate the variance contribution rate of the principal component vector, sort the variance contribution rates from large to small, and select the principal component vectors corresponding to the first two variance contribution rates as evaluation vectors;

[0047] S4: Calculate the contribution of different cracking indicators in the two evaluation vectors, and establish an evaluation model for the anti-cracking performance of thermosetting epoxy modified asphalt mixture based on the contribution of different cracking indicators in the two evaluation vectors to evaluate the anti-cracking performance of the thermosetting epoxy modified asphalt mixture.

[0048] Specifically, specimens were prepared for semicircular bending tests with different thermosetting epoxy modified asphalt content, tested at three different test temperatures, and the cracking index information of the specimens was recorded during the test. By preparing specimens for semicircular bending tests with different thermosetting epoxy modified asphalt content and testing them under multiple temperature conditions, the crack resistance and temperature sensitivity of epoxy modified asphalt mixtures can be systematically evaluated, providing a data basis for constructing an evaluation model, ensuring that the data can cover most temperatures and have applicability;

[0049] Secondly, principal component analysis was used to determine the principal component coefficients of all specimen cracking index information and construct independent principal component vectors reflecting all specimen cracking index information. Principal component analysis can project high-dimensional data into a low-dimensional space, reducing the number of variables while retaining most of the original information. In addition, principal component analysis can reveal similarities between different index data and retain as much unrelated principal component information as possible, making the data easier to analyze.

[0050] Thirdly, the variance contribution rate of the principal component vector is solved, the variance contribution rates are sorted from large to small, and the principal component vectors corresponding to the first two variance contribution rates are selected as evaluation vectors. This can effectively eliminate duplicate information and redundant features between data while retaining the core information of the original data, providing an orthogonalized low-dimensional feature space for subsequent modeling.

[0051] Finally, the contribution of different cracking indicators in the two evaluation vectors is calculated, and based on the contribution of different cracking indicators in the two evaluation vectors, an evaluation model for the anti-cracking performance of thermosetting epoxy modified asphalt mixture is established to evaluate the anti-cracking performance of thermosetting epoxy modified asphalt mixture. The contribution calculation can objectively reflect the influence weight of each SCB indicator on the anti-cracking performance, avoid the subjectivity in traditional empirical evaluation, and integrate multiple SCB indicators to more comprehensively guarantee the anti-cracking performance and improve the accuracy of the evaluation model. It has strong engineering practicality and can provide precise guidance for the anti-cracking design of thermosetting epoxy modified asphalt mixture, reduce the cost of trial and error, and improve pavement durability.

[0052] In a specific embodiment, specimens with different thermosetting epoxy modified asphalt content for semicircular bending test were prepared, different specimens were tested at three test temperatures, and the cracking index information of the specimens during the test was recorded as follows:

[0053] In this scheme, specimens with thermosetting epoxy modified asphalt content of 30%, 40% and 50% were prepared for semicircular bending test. The semicircular bending test was carried out at test temperatures of -10℃, 15℃ and 25℃, and the cracking index information of the specimens during the test was recorded:

[0054] First, the present invention prepares three types of thermosetting epoxy modified asphalt mixtures by adding different contents of thermosetting epoxy resin modified asphalt to three groups of the same aggregate, and makes them into specimens for semicircular bending tests;

[0055] Secondly, semicircular bending tests were carried out on the specimens at -10℃, 15℃ and 25℃ respectively. The pre-peak fracture energy, post-peak fracture energy, total fracture energy, flexural strength, FI value, crack resistance index and crack initiation index of various asphalt mixtures at different temperatures were recorded by DIC technology and acoustic emission equipment. SCB test and collection of test index information such as Figure 2 As shown in the figure, the test environment temperature and the load applied by the roller to the mixture specimen are adjusted by the buttons on the test bench equipment. The displacement photos of the asphalt mixture at different temperatures are taken using a DIC camera. The elastic waves released when the asphalt breaks are captured using an acoustic emission sensor. The acoustic emission signal parameters (amplitude, energy, frequency, rise time, etc.) are analyzed to locate the damage source and determine the damage type. The expressions of the various cracking index information are shown in formula (9).

[0056]

[0057] Where M i-峰前-t 、M i-峰后-t 、M i-总裂-t 、M i-弯拉-t 、M i-FI-t 、M i-抗裂-t and Mi-裂萌-t They represent the pre-peak fracture energy, post-peak fracture energy, total fracture energy, flexural strength, FI value, crack resistance index and crack initiation index of the specimen with a thermosetting epoxy modified asphalt content of i% during the test at temperature t; 峰前,i,t 、x 峰后,i,t 、x 总裂,i,t 、x 弯拉,i,t 、x FI,i,t 、x 抗裂,i,t and x 裂萌,i,t They represent the data points corresponding to the cracking index information, and the final test data are shown in Table 1:

[0058] Table 1

[0059]

[0060]

[0061] In this scheme, by preparing semi-circular bend test (SCB, Semi-Circular Bend) specimens with different thermosetting epoxy modified asphalt content and testing them under multiple temperature conditions, the crack resistance and temperature sensitivity of thermosetting epoxy modified asphalt mixtures can be systematically evaluated, providing a data basis for constructing an evaluation model, ensuring that the data can cover most temperatures and is applicable.

[0062] In a specific embodiment, the principal component analysis method is used to determine the principal component coefficients of the cracking index information of all specimens, and the scheme for constructing the principal component vectors that reflect the cracking index information of all specimens and are independent of each other is:

[0063] S21. Standardize all semicircular bending test data using the range standardization method and calculate the correlation matrix of the semicircular bending test data at three test temperatures, as shown in formula (10).

[0064]

[0065] Where R -10 、R 15 and R 25 Represents the correlation matrix of semicircular bending test data under three test temperatures; X -10 、X 15 and X 25 Represents the data vector matrix of 7 cracking indicators under three test temperatures; x1 -10 ~x7 -10 、x1 15 ~x7 15 、x1 25 ~x7 25 are the data vectors of seven cracking indices at three test temperatures;

[0066] S22. Solve the principal component coefficient matrix and its covariance matrix in the test data at three test temperatures, as shown in formula (11),

[0067]

[0068] Where A -10 、A 15 and A 25 Represents the principal component coefficient matrix of the cracking index information at three test temperatures; C -10 、C 15 and C 25 They represent the covariance matrices of the cracking index information at three test temperatures; E is the identity matrix; are the principal component coefficients of the seven cracking index information at three test temperatures, are the covariances of the cracking index information at three test temperatures;

[0069] S23, construct the comprehensive principal component coefficient matrix and the principal component vector of the specimen, as shown in formula (12),

[0070]

[0071] Where A c is the comprehensive principal component coefficient matrix; Y1, Y2, Y3, Y4, Y5, Y6 and Y7 represent the principal component vectors of the seven cracking indices, and X1, X2, X3, X4, X5, X6 and X7 represent the pre-peak fracture energy, post-peak fracture energy, total fracture energy, flexural strength, FI value, crack resistance index and crack initiation index, respectively.

[0072] In this approach, principal component analysis (PCA) can project high-dimensional data into a low-dimensional space, reducing the number of variables while retaining most of the original information. Furthermore, PCA can reveal similarities between different indicator data and preserve as much unrelated principal component information as possible, making the data easier to analyze.

[0073] In a specific embodiment, the variance contribution rates of the principal component vectors are calculated, the variance contribution rates are sorted from large to small, and the principal component vectors corresponding to the first two variance contribution rates are selected as the evaluation vectors. The solution is:

[0074] The calculation formula of variance contribution rate is shown in (13),

[0075]

[0076] Where Var(Y1), Var(Y2), Var(Y3), Var(Y4), Var(Y5), Var(Y6) and Var(Y7) represent the variance contribution rates of the seven principal component vectors respectively;

[0077] The variance contribution rates are sorted from large to small, and the principal component vectors corresponding to the first two variance contribution rates are selected as evaluation vectors, which are recorded as PCA1 and PCA2.

[0078] In this scheme, the principal component vector with the largest variance contribution rate is selected as the main vector, which can effectively eliminate duplicate information and redundant features between data while retaining the core information of the original data, and provide an orthogonal low-dimensional feature space for subsequent modeling.

[0079] In a specific embodiment, the contribution of different cracking indices in two evaluation vectors is calculated, and an evaluation model for the crack resistance of thermosetting epoxy modified asphalt mixture is established based on the contribution of different cracking indices in the two evaluation vectors. The scheme for evaluating the crack resistance of thermosetting epoxy modified asphalt mixture is:

[0080] S41. Project the data vectors of the seven cracking indices of all semicircular bending test data at three test temperatures onto PCA1 and PCA2, as follows: Figure 3 As shown, the projection values ​​of each indicator on PCA1 and PCA2, that is, the contribution, are calculated as shown in formula (14).

[0081]

[0082] Wherein, PCA1_contri(Y1), PCA1_contri(Y2), PCA1_contri(Y3), PCA1_contri(Y4), PCA1_contri(Y5), PCA1_contri(Y6) and PCA1_contri(Y7) represent the contribution rates of the seven cracking indices on the PCA1 vector; PCA2_contri(Y1), PCA2_contri(Y2), PCA2_contri(Y3), PCA2_contri(Y4), PCA2_contri(Y5), PCA2_contri(Y6) and PCA2_contri(Y7) represent the contribution rates of the seven cracking indices on the PCA2 vector;

[0083] S42. Calculate PCA1 and PCA2 according to formula (14), as shown in formula (15).

[0084]

[0085] S43. Based on the variance contribution rate of PCA1 and PCA2 and the contribution of cracking index on PCA1 and PCA2, an evaluation model for the cracking resistance of thermosetting epoxy modified asphalt mixture is constructed, as shown in formula (16).

[0086]

[0087] Among them, CCRI is the comprehensive crack resistance performance, Var1 and Var2 represent the variance contribution rates of vectors PCA1 and PCA2, respectively.

[0088] Where CCRI is the comprehensive crack resistance. In this scheme, PCA1 = -0.201 × pre-peak fracture energy + 0.628 × post-peak fracture energy + 0.116 × total fracture energy + (-0.481) × flexural strength + 0.853 × crack resistance index + 0.982 × FI value + 0.953 × crack initiation index; PCA2 = 0.879 × pre-peak fracture energy + 0.457 × post-peak fracture energy + 0.979 × total fracture energy + 0.587 × flexural strength + (-0.367) × crack resistance index + (-0.132) × FI value + (-0.028) × crack initiation index.

[0089] In this scheme, the contribution calculation can objectively reflect the influence weight of each SCB indicator on the anti-cracking performance, avoiding the subjectivity in traditional empirical evaluation. The integration of multiple SCB indicators can more comprehensively guarantee the anti-cracking performance and improve the accuracy of the evaluation model. It has strong engineering practicality and can provide precise guidance for the anti-cracking design of thermosetting epoxy modified asphalt mixtures, reduce the cost of trial and error, and improve the durability of the pavement.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for evaluating the comprehensive anti-cracking performance of thermosetting epoxy modified asphalt mixture, characterized in that: include: S1: Prepare specimens for semicircular bending test with different thermosetting epoxy modified asphalt content, test the specimens at three test temperatures, and record the cracking index information of the specimens during the test; S2: Use the principal component analysis method to determine the principal component coefficients of the cracking index information of all specimens, and construct a principal component vector that reflects the cracking index information of all specimens and is independent of each other; S3: Calculate the variance contribution rate of the principal component vector, sort the variance contribution rates from large to small, and select the principal component vectors corresponding to the first two variance contribution rates as evaluation vectors; S4: Calculate the contribution of different cracking indicators in the two evaluation vectors, and establish an evaluation model for the anti-cracking performance of thermosetting epoxy modified asphalt mixture based on the contribution of different cracking indicators in the two evaluation vectors to evaluate the anti-cracking performance of the thermosetting epoxy modified asphalt mixture.

2. The method for evaluating the comprehensive crack resistance of thermosetting epoxy modified asphalt mixture according to claim 1, characterized in that: The cracking index information includes pre-peak fracture energy, post-peak fracture energy, total fracture energy, flexural strength, FI value, crack resistance index and crack initiation index. The expressions of each cracking index information are shown in formula (1): Where M i-峰前-t 、M i-峰后-t 、M i-总裂-t 、M i-弯拉-t 、M i-FI-t 、M i-抗裂-t and M i-裂萌-t They represent the pre-peak fracture energy, post-peak fracture energy, total fracture energy, flexural strength, FI value, crack resistance index and crack initiation index of the specimen with a thermosetting epoxy modified asphalt content of i% during the test at temperature t; 峰前,i,t 、x 峰后,i,t 、x 总裂,i,t 、x 弯拉,i,t 、x FI,i,t 、x 抗裂,i,t and x 裂萌,i,t They represent the data points corresponding to the cracking index information.

3. The method for evaluating the comprehensive crack resistance of thermosetting epoxy modified asphalt mixture according to claim 2, characterized in that: The principal component analysis method is used to determine the principal component coefficients of the cracking index information of all specimens, and a principal component vector that reflects the cracking index information of all specimens and is independent of each other is constructed, including: S21. Standardize all semicircular bending test data using the range standardization method and calculate the correlation matrix of the semicircular bending test data at three test temperatures, as shown in formula (2). Where R -10 、R 15 and R 25 Represents the correlation matrix of semicircular bending test data under three test temperatures; X -10 、X 15 and X 25 Represents the data vector matrix of 7 cracking indicators under three test temperatures; x1 -10 ~x7 -10 、x1 15 ~x7 15 、x1 25 ~x7 25 are the data vectors of seven cracking indices at three test temperatures; S22. Solve the principal component coefficient matrix and its covariance matrix in the test data at three test temperatures, as shown in formula (3). Where A -10 、A 15 and A 25 Represents the principal component coefficient matrix of the cracking index information at three test temperatures; C -10 、C 15 and C 25 They represent the covariance matrices of the cracking index information at three test temperatures; E is the identity matrix; are the principal component coefficients of the seven cracking index information at three test temperatures, are the covariances of the cracking index information at three test temperatures; S23, construct the comprehensive principal component coefficient matrix and the principal component vectors of all specimens, as shown in formula (4), Where A c is the comprehensive principal component coefficient matrix; Y1, Y2, Y3, Y4, Y5, Y6 and Y7 represent the principal component vectors of the seven cracking indices, and X1, X2, X3, X4, X5, X6 and X7 represent the pre-peak fracture energy, post-peak fracture energy, total fracture energy, flexural strength, FI value, crack resistance index and crack initiation index, respectively.

4. The method for evaluating the comprehensive crack resistance of thermosetting epoxy modified asphalt mixture according to claim 3, characterized in that: Solve the variance contribution rate of the principal component vector, sort the variance contribution rates from large to small, and select the principal component vectors corresponding to the first two variance contribution rates as evaluation vectors, including, The calculation formula of variance contribution rate is shown in (5). Where Var(Y1), Var(Y2), Var(Y3), Var(Y4), Var(Y5), Var(Y6) and Var(Y7) represent the variance contribution rates of the seven principal component vectors respectively; The variance contribution rates are sorted from large to small, and the principal component vectors corresponding to the first two variance contribution rates are selected as evaluation vectors, which are recorded as PCA1 and PCA2.

5. The method for evaluating the comprehensive anti-cracking performance of a thermosetting epoxy modified asphalt mixture according to claim 4, wherein: The contribution of different cracking indices in the two evaluation vectors is calculated, and based on the contribution of different cracking indices in the two evaluation vectors, an evaluation model for the crack resistance of thermosetting epoxy modified asphalt mixture is established to evaluate the crack resistance of thermosetting epoxy modified asphalt mixture, including: S41. Project the data vectors of the seven cracking indices of all semicircular bending test data at three test temperatures onto PCA1 and PCA2, and calculate the projection value of each index on PCA1 and PCA2, i.e., the contribution, as shown in formula (6): Wherein, PCA1_contri(Y1), PCA1_contri(Y2), PCA1_contri(Y3), PCA1_contri(Y4), PCA1_contri(Y5), PCA1_contri(Y6) and PCA1_contri(Y7) represent the contribution rates of the seven cracking indices on the PCA1 vector; PCA2_contri(Y1), PCA2_contri(Y2), PCA2_contri(Y3), PCA2_contri(Y4), PCA2_contri(Y5), PCA2_contri(Y6) and PCA2_contri(Y7) represent the contribution rates of the seven cracking indices on the PCA2 vector; S42. Calculate PCA1 and PCA2 according to formula (6), as shown in formula (7). S43. Based on the variance contribution rate of PCA1 and PCA2 and the contribution of cracking index on PCA1 and PCA2, the evaluation model of anti-cracking performance of thermosetting epoxy modified asphalt mixture is constructed, as shown in formula (8). Among them, CCRI is the comprehensive crack resistance performance, Var1 and Var2 represent the variance contribution rates of vectors PCA1 and PCA2, respectively.

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