Comprehensive evaluation method for influence factors of asphalt-aggregate interface bonding strength

Abstract

The invention discloses a comprehensive evaluation method for asphalt-aggregate interface bonding strength influence factors, which comprises the following steps: (1) collecting and screening historical data of the factors influencing the asphalt-aggregate interface bonding strength, and establishing an asphalt-aggregate interface drawing strength evaluation system; (2) carrying out the following pretreatment on the aggregate to prepare an asphalt-aggregate interface drawing sample; (3) the drawing rate is set, and the drawing strength corresponding to the multiple drawing samples is tested; (4) comprehensively evaluating the drawing strength by using a conjoint analysis method; good adhesion between the asphalt and the aggregate is ensured, and the performance and durability of the asphalt mixture are improved.

Description

Technical Field

[0001] The invention relates to the technical field of adhesion performance evaluation, and in particular to a comprehensive evaluation method for factors affecting asphalt-aggregate interface bonding strength. Background Art

[0002] The bonding strength between asphalt and aggregate is an important factor that determines the overall performance stability of asphalt mixtures and even asphalt pavements. This bonding strength is mainly determined by the cohesion of asphalt, the adhesion between asphalt and aggregate, and the strength of the aggregate itself. How to effectively measure the bonding strength of the asphalt-aggregate interface and analyze its influencing factors is crucial to improving the performance and durability of asphalt mixtures.

[0003] Prior art: A test device and method for testing the asphalt-aggregate interface adhesion, which can qualitatively compare the interface adhesion effects of different types of asphalt and aggregate, but cannot quantify the size of the interface adhesion energy; although the Binder Bond Strength (BBS) test published by AASHTOTP91-2015 can quantify the interface adhesion strength between asphalt and aggregate, the asphalt binder bonding strength is determined by the adhesive bond strength (BBS) test, and the analysis factors of the adhesion strength are relatively single, which cannot meet the analysis and evaluation of multiple factors affecting the asphalt-aggregate interface bonding strength, resulting in low accuracy of the factor evaluation results. Summary of the invention

[0004] Purpose of the invention: The purpose of the present invention is to provide a comprehensive evaluation method for factors affecting the asphalt-aggregate interface bond strength, so as to solve the problems that the existing comprehensive analysis of factors affecting the asphalt-aggregate interface bond strength cannot be quantified and the evaluation results are not accurate.

[0005] Technical solution: A comprehensive evaluation method for factors affecting asphalt-aggregate interface bonding strength according to the present invention comprises the following steps:

[0006] (1) Collect and screen historical data on factors affecting the asphalt-aggregate interface bond strength, and establish an asphalt-aggregate interface pull-out strength evaluation system;

[0007] (2) The aggregate is pretreated as follows to prepare asphalt-aggregate interface pull-out specimens;

[0008] (3) setting the pulling rate and testing the pulling strength corresponding to a plurality of pulling specimens;

[0009] (4) Use the combined analysis method to comprehensively evaluate the pull-out strength.

[0010] Furthermore, step (1) is specifically as follows: collect historical data on factors affecting the asphalt-aggregate interface bonding strength, screen out factors that have a significant impact on the asphalt-aggregate interface bonding strength, and take multiple levels for each factor; use orthogonal experiments to construct multiple asphalt-aggregate interface tensile strength evaluation systems.

[0011] Furthermore, in step (1), the historical data of factors affecting the asphalt-aggregate interface bonding strength include: asphalt film thickness, asphalt type, aggregate type, aging effect, and dry or wet environment.

[0012] Furthermore, in step (1), the thickness of the asphalt film is 0.1 mm-0.8 mm; the type of asphalt is 70#-90#; the type of aggregate is quartz, calcite, and albite; and the aging effect is unaged, short-term aged, and long-term aged.

[0013] Furthermore, the pretreatment of step (2) is as follows: the surface of the aggregate is cut and polished until the surface is flat, cleaned, dried, and then polished with 220-mesh sandpaper; after polishing, the surface of the aggregate is cleaned and dried, and then cooled to room temperature after drying.

[0014] Furthermore, the drying temperature is 80°C ± 5°C, and the drying time is 1h to 2h.

[0015] Furthermore, in step (2), when preparing the drawing specimen, the short-term aging of the asphalt is as follows: the temperature of the rotary thin film oven is set to 163°C ± 0.5°C, and preheated for not less than 16 hours; then 35g ± 0.5g of asphalt is added, and the asphalt is placed in the rotary thin film oven for 85 minutes to complete the short-term aging of the asphalt;

[0016] Long-term aging of asphalt is as follows: short-term aged asphalt is placed in a pressure aging test instrument for 20h±10min at a temperature of 90-110℃ and a pressure of 2.1MPa to complete the long-term aging of asphalt;

[0017] The water environment is as follows: the asphalt-aggregate specimens prepared according to the asphalt type, asphalt film thickness, aggregate type and aging effect are first placed at room temperature for 1 hour; then the asphalt-aggregate specimens are completely immersed in a water bath at 60±1℃ for 24 hours, and finally placed in a dry environment for 1 hour to room temperature.

[0018] Further, step (4) includes the following steps:

[0019] (41) Constructing a sample matrix X: Constructing a sample matrix X according to the evaluation system in step (1), wherein each column of the sample matrix X represents an evaluation system for the tensile strength of the asphalt-aggregate interface; each row of the sample matrix X consists of (X0, ..., X ij )composition;

[0020] Among them: X0 is a constant term, which is 1; i is the number of factors, j is the number of levels for each factor, and X ij Is the influencing factor i taking the jth level, if yes then X ij The value is 1, otherwise X ij The value is 0;

[0021] (42)Construct multivariate linear equation:

[0022] y=XA (1)

[0023] Among them, the constant vector y is the pull-out strength corresponding to the pull-out specimen prepared by each asphalt-aggregate interface pull-out strength evaluation scheme; A is the correlation coefficient of the sample matrix, which is also the utility value a corresponding to each level of the constant term and multiple factors. i The column vector is composed of; i is the number of factors;

[0024] Transform formula (1) to calculate the correlation coefficient A of the sample matrix

[0025] A=(X T X) -1 X T y (2)

[0026] (43) Calculate the importance value I of each factor i :

[0027] According to the calculated correlation coefficient A, the importance value I of each factor is calculated using the following formula i ;

[0028] I i =|a imax -a imin | (3)

[0029] Among them, a imax is the utility value a corresponding to each level under the i-th factor i The maximum value of a imin is the utility value a corresponding to each level under the i-th factor i The minimum value of

[0030] (44) Calculate the importance F of each factor i

[0031] According to the importance value I i Calculate the importance of each factor F i , the calculation formula is as follows:

[0032]

[0033] Where: n is the maximum value of factor i, which is a positive integer;

[0034] (45) Comprehensive evaluation: importance of calculation F i The sizes of the factors are ranked to determine the importance of the factors affecting the asphalt-aggregate interface bond strength.

[0035] An electronic device described in the present invention includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the computer program is loaded into the processor, any one of the methods for planning a flight path for a drone is implemented.

[0036] A storage medium described in the present invention stores a computer program, and when the computer program is executed by a processor, it implements any one of the methods for planning a flight path for an unmanned aerial vehicle.

[0037] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: by constructing an asphalt-aggregate interface pull-out strength evaluation scheme and a pull-out strength test, and then using a joint analysis method to comprehensively evaluate the factors affecting the asphalt-aggregate interface bonding strength (such as asphalt film thickness, asphalt type, aggregate type, aging effect, dry / water environment), the importance of the factors affecting the asphalt-aggregate interface bonding strength is determined by the importance of the factors, and the factors affecting the asphalt-aggregate interface bonding strength are quantitatively evaluated and analyzed. By analyzing the importance of the asphalt-aggregate interface bonding strength, a material combination with better comprehensive performance can be selected to ensure good adhesion between asphalt and aggregate, and improve the performance and durability of asphalt mixtures; the comprehensive evaluation method provided can screen out the optimal ratio design of the asphalt-aggregate interface bonding strength according to the calculated utility value of each factor level, so as to determine the technical measures for asphalt-aggregate mixing and guide the construction process, thereby enhancing the adhesion performance between the asphalt-aggregate interface. Therefore, the evaluation method of the present invention is of great significance to improving the service life of asphalt pavement. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0039] The technical solution of the present invention is further described below in conjunction with the accompanying drawings.

[0040] like Figure 1 As shown, an embodiment of the present invention provides a comprehensive evaluation method for factors affecting asphalt-aggregate interface bonding strength, comprising the following steps:

[0041] S1. Constructing a tensile strength evaluation scheme for the asphalt-aggregate interface

[0042] Historical data on factors affecting the asphalt-aggregate interface bond strength were collected, and factors with significant influence on the asphalt-aggregate interface bond strength were screened out. Each factor had multiple levels. Multiple asphalt-aggregate interface pull-out strength evaluation schemes were constructed using orthogonal experiments.

[0043] Among them, the factors that have a significant impact on the asphalt-aggregate interface bond strength include: asphalt film thickness, asphalt type, aggregate type, aging effect and dry / water environment. Since the asphalt film thickness is 0.1mm-0.8mm, the asphalt film thickness is 0.1mm, 0.2mm, 0.4mm, 0.6mm and 0.8mm. The asphalt types are two commonly used asphalts on pavements, namely 70# asphalt and 90# asphalt. The aggregate types are the main mineral components of several commonly used aggregates on roads, quartz, calcite and albite. The aging effect considers unaged, short-term aging and long-term aging. The dry / water environment is dry and water.

[0044] S2. Preparation of asphalt-aggregate interface pull-out specimens

[0045] According to the multiple asphalt-aggregate interface pull-out strength evaluation schemes constructed above, a corresponding multiple pull-out specimens are prepared.

[0046] In step S2 of the present invention, the aggregate is pretreated as follows before preparing the drawing specimen: the aggregate surface is cut and polished until the surface is flat, cleaned, and then dried and polished with 220-grit sandpaper; after polishing, the aggregate surface is cleaned and dried, and then cooled to room temperature after drying. The drying temperature is 80°C ± 5°C, and the drying time is 1h to 2h.

[0047] In step S2 of the present invention, when preparing the drawing specimen, the short-term aging of the asphalt is as follows: the temperature of the rotary thin film oven is set to 163°C ± 0.5°C, and preheated for not less than 16 hours; then 35g ± 0.5g of asphalt is added, and the asphalt is placed in the rotary thin film oven for 85 minutes to complete the short-term aging of the asphalt.

[0048] In step S2 of the present invention, when preparing the drawing specimen, the long-term aging of the asphalt is: the short-term aged asphalt is placed in a pressure aging test instrument for 20h±10min at a temperature of 90-110°C and a pressure of 2.1MPa to complete the long-term aging of the asphalt.

[0049] In step S2 of the present invention, when preparing the pulling specimen, the water environment means: the asphalt-aggregate specimen prepared according to the asphalt type, asphalt film thickness, aggregate type and aging effect is first placed at room temperature for 1 hour; then the asphalt-aggregate specimen is placed in a water bath environment at 60±1°C and completely immersed for 24 hours, and finally placed in a dry environment for 1 hour to room temperature.

[0050] S3. Asphalt-aggregate interface bond strength test

[0051] The pulling rate is set, and the pulling strengths corresponding to the plurality of pulling samples in step S2 are measured respectively. The pulling rate is set to 0.7 MP / s.

[0052] S4. Comprehensive evaluation using conjoint analysis

[0053] S41, constructing a sample matrix X;

[0054] According to step S1, multiple asphalt-aggregate interface pull-out strength evaluation schemes are constructed, and a sample matrix X is constructed. Each column of the sample matrix X represents an asphalt-aggregate interface pull-out strength evaluation scheme; each row of the sample matrix X is composed of (X0, ..., X ij )composition;

[0055] Among them: X0 is a constant term, which is 1; i is the number of factors, j is the number of levels for each factor, and X ij Is the influencing factor i taking the jth level, if yes then X ij The value is 1, otherwise X ij The value is 0;

[0056] S42, construct multivariate linear equations;

[0057] y=XA (1)

[0058] Where: the constant vector y is the pull-out strength corresponding to the pull-out specimen prepared by each asphalt-aggregate interface pull-out strength evaluation scheme; A is the correlation coefficient of the sample matrix, which is also the utility value a corresponding to each level of the constant term and multiple factors. i The column vector is composed of; i is the number of factors;

[0059] S43, transform formula (1) to calculate the correlation coefficient A of the sample matrix

[0060] A=(X T X) -1 X T y (2)

[0061] S44. Calculate the importance value I of each factor i

[0062] According to the correlation coefficient A calculated in step S43, the importance value I of each factor is calculated using the following formula: i ;

[0063] I i =|a imax -a imin | (3)

[0064] Where: aimax is the utility value a corresponding to each level under the i-th factor i The maximum value of a imin is the utility value a corresponding to each level under the i-th factor i The minimum value of

[0065] S45. Calculate the importance of each factor F i

[0066] According to the importance value I in step S44 i Calculate the importance of each factor F i , the calculation formula is as follows:

[0067]

[0068] Where: n is the maximum value of factor i, which is a positive integer;

[0069] S46. Comprehensive evaluation

[0070] The importance of the above calculation F i The sizes of the factors are ranked to determine the importance of the factors affecting the asphalt-aggregate interface bond strength.

[0071] Specific experiments:

[0072] The comprehensive evaluation method for factors affecting the asphalt-aggregate interface bonding strength provided by the present invention is described in detail below with reference to preferred embodiments.

[0073] Example

[0074] like Figure 1 As shown, this embodiment provides a comprehensive evaluation method for factors affecting asphalt-aggregate interface bonding strength, comprising the following steps:

[0075] S1. Constructing a tensile strength evaluation scheme for the asphalt-aggregate interface

[0076] Historical data on factors affecting the asphalt-aggregate interface bond strength were collected, and factors with significant influence on the asphalt-aggregate interface bond strength were screened out. Each factor had multiple levels. Multiple asphalt-aggregate interface pull-out strength evaluation schemes were constructed using orthogonal experiments.

[0077] In this embodiment, by analyzing the historical data of the research results on the pull-out strength of the asphalt-aggregate interface in the past 10 years and combining it with expert experience, five factors with more significant influence are selected from the many factors affecting the pull-out strength of the asphalt-aggregate interface: asphalt film thickness, asphalt type, aggregate type, aging effect and dry / water environment.

[0078] For the above five factors, the asphalt film thickness takes five levels: 0.1mm, 0.2mm, 0.4mm, 0.6mm, and 0.8mm; the asphalt type takes two levels: 70# asphalt and 90# asphalt; the aggregate type takes three levels: quartz, calcite, and albite; the aging effect takes three levels: unaged, short-term aging, and long-term aging; the dry / water environment takes two levels: dry and water.

[0079] According to the five selected factors and the corresponding levels of each factor, multiple asphalt-aggregate interface pull-out strength evaluation schemes were constructed using orthogonal tests. A total of 25 asphalt-aggregate interface pull-out strength evaluation schemes were constructed, as shown in Table 1.

[0080] Table 1 Evaluation scheme table constructed by orthogonal experiment

[0081]

[0082]

[0083] S2. Preparation of asphalt-aggregate interface pull-out specimens

[0084] According to the 25 asphalt-aggregate interface pull-out strength evaluation schemes constructed above, 25 corresponding pull-out specimens were prepared.

[0085] In this embodiment, the drawing sample preparation includes the following steps:

[0086] (1) Asphalt aging treatment

[0087] In order to improve the accuracy of the evaluation of the influence of asphalt type and aging on the asphalt-aggregate interface bond strength, the asphalt rotating thin film heating test (RTFOT) was carried out on 70# asphalt and 90# asphalt according to the Test Procedure for Asphalt and Asphalt Mixtures in Highway Engineering (JTG E20-2011) for aging.

[0088] Specifically: the temperature of the rotary thin film oven is set to 163℃±0.5℃. In order to ensure that the air in the oven is heated evenly, the oven is preheated at the set temperature for no less than 16 hours. 35g±0.5g of asphalt is added to the sample bottle required by the specification, and the bottle is placed in the rotary thin film oven for 85 minutes before the asphalt is taken out to obtain short-term aging.

[0089] Long-term asphalt aging is the short-term aging obtained by the rotating film heating test of asphalt, and the pressure aging container accelerated asphalt aging test (PAV) specified in the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG E20-2011). During PAV aging, the asphalt is placed in the pressure aging test instrument for 20h±10min, the temperature is 90-110℃, and the pressure is 2.1MPa to obtain long-term aging.

[0090] (2) Aggregate processing

[0091] The following treatments were performed on the aggregates: the surfaces of the three minerals were cut and polished until the surface was flat, cleaned, and dried, and then polished with 220-mesh sandpaper; after polishing, they were cleaned and then placed in an oven for drying. The oven temperature was set to 80°C, and they were taken out after 1 hour and cooled to room temperature.

[0092] (3) Preparation of pull-out specimens with different asphalt film thicknesses: The prepared asphalt was placed in an oven at 110°C for 0.5 h to heat the asphalt until it was in a fluid state. Asphalt in different aged states was spread evenly on the surface of the treated aggregate. The asphalt film thickness was measured and controlled by a vernier caliper to be 0.1 mm, 0.2 mm, 0.4 mm, 0.6 mm and 0.8 mm respectively. The pulling die for the pulling test was placed on the surface of the aggregate with different film thicknesses to prepare the asphalt-aggregate interface pulling specimens. The specimens were left to stand at room temperature for 24 h before the pulling specimens were measured.

[0093] According to the asphalt type (70# asphalt and 90# asphalt), aging effect (unaged, short-term aged and long-term aged), aggregate type (quartz, calcite and albite) and asphalt film thickness in Table 1, asphalt-aggregate pull-out specimens were prepared and the interface bonding strength test was carried out.

[0094] Furthermore, if the influence of water environment on the interfacial bonding strength is considered, the prepared asphalt-aggregate pull-out specimen is placed at room temperature for 1 hour, and then the asphalt-aggregate pull-out specimen is completely immersed in a water bath at 60±1℃ for 24 hours. Finally, it is taken out and placed in a dry environment for 1 hour until it reaches room temperature before the pull-out test is carried out.

[0095] S3. Asphalt-aggregate interface bond strength test

[0096] The pulling rate is set, and the pulling strengths corresponding to the 25 pulling samples in step S2 are measured respectively.

[0097] In this embodiment, the pull-out strength test includes the following steps: using the PosiTest AT-A fully automatic digital display pull-out adhesion tester to perform a pull-out test on the prepared asphalt-aggregate sample, the pull-out rate is set to 0.7MP / s, and during the test, ensure that the pull-out tester and the sample are in a vertical state.

[0098] In order to ensure the accuracy of the measurement results, at least three sets of parallel tests were conducted on each pull-out specimen to ensure that the mean square error of the three test results did not exceed 0.2. The average value was finally taken as the pull-out strength output for subsequent evaluation and analysis. The pull-out strength results corresponding to the 25 pull-out specimens are shown in Table 2.

[0099] Table 2 Experimental test results

[0100] Evaluation plan Asphalt film thickness Asphalt Type Aggregate Type Aging Effects Water Pull-out strength / MPa 1 0.1mm 70# Quartz Short-term aging Water 2.23 2 0.1mm 70# Calcite Long-term aging Water 2.06 3 0.1mm 70# Quartz Not aged dry 3.21 4 0.1mm 90# Calcite Not aged dry 3.26 5 0.1mm 90# Sodium feldspar Short-term aging dry 3.92 6 0.2mm 90# Quartz Not aged Water 1.81 7 0.2mm 70# Quartz Short-term aging Water 2.01 8 0.2mm 70# Calcite Long-term aging dry 2.79 9 0.2mm 90# Calcite Short-term aging dry 3.13 10 0.2mm 70# Sodium feldspar Not aged dry 3.61 11 0.4mm 90# Quartz Not aged Water 1.71 12 0.4mm 90# Sodium feldspar Long-term aging Water 2.22 13 0.4mm 70# Quartz Short-term aging dry 2.85 14 0.4mm 70# Calcite Not aged dry 2.84 15 0.4mm 70# Calcite Short-term aging dry 3.11 16 0.6mm 90# Calcite Not aged Water 1.73 17 0.6mm 70# Sodium feldspar Short-term aging Water 2.31 18 0.6mm 70# Quartz Long-term aging dry 2.37 19 0.6mm 70# Quartz Not aged dry 2.64 20 0.6mm 90# Calcite Short-term aging dry 2.82 21 0.8mm 70# Calcite Not aged Water 1.71 22 0.8mm 70# Calcite Short-term aging Water 1.75 23 0.8mm 90# Quartz Long-term aging dry 2.26 24 0.8mm 90# Quartz Short-term aging dry 2.56 25 0.8mm 70# Sodium feldspar Not aged dry 3.32

[0101] S4, S41, construct sample matrix X

[0102] According to step S1, multiple asphalt-aggregate interface pull-out strength evaluation schemes are constructed, and a sample matrix X is constructed. Each column of the sample matrix X represents an asphalt-aggregate interface pull-out strength evaluation scheme; each row of the sample matrix X is composed of (X0, ..., X ij ) where: X0 is a constant term, which is 1; i is the number of factors, j is the number of levels for each factor, and X ij Is the influencing factor i taking the jth level, if yes then X ij The value is 1, otherwise X ij The value is 0.

[0103] In this embodiment, since 25 asphalt-aggregate interface pull-out strength evaluation schemes are constructed, the sample matrix X has 25 rows, each of which is composed of (X0, ...X ij )composition.

[0104] In this embodiment, i is the number of factors, j is the level number of each factor, and i is 1, 2, 3, 4, and 5. Specifically, the first factor is the asphalt film thickness, and j is 1, 2, 3, 4, and 5; the second factor is the asphalt type, and j is 1, 2; the third factor is the asphalt type, and j is 1, 2, and 3; the fourth factor is the aging effect, and j is 1, 2, and 3; the fifth factor is whether there is water, and j is 1, 2. ij Is whether factor i takes the jth level. When the corresponding i-th factor takes the jth level, then X ij is 1, otherwise, when the corresponding i-th factor does not take the j-th level, then X ij The value is 0.

[0105] Therefore, in the sample matrix X, the first row is (1,1,0,0,0,0,1,0,1,0,0,0,1,0,0,1), and the first 1 is the constant term X0. The second 1 is X 11 , the factor is the asphalt film thickness, and the level is 0.1 mm. This is because in Table 1, in the first evaluation scheme, the asphalt film thickness is 0.1 mm, so X 11 The value is 1; if the asphalt film thickness does not take other levels, then X 12 , X 13 , X 14 , X 15 The value is 0. The third 1 is X 21 , indicating that the factor is the type of asphalt, and the impact level is 70# asphalt. This is because in Table 1, in the first evaluation scheme, the type of asphalt is 70# asphalt, so X 21The value is 1; therefore, the other levels of asphalt types X 22 The value is 0. The fourth 1 is X 31 , indicating that the influencing factor is the type of aggregate and the influencing level is quartz. This is because in Table 1, in the first evaluation scheme, the type of aggregate is quartz, so X 31 The value is 1; other levels of aggregate types X 32 , X 33 The value is 0. The fourth 1 is X 42 , indicating that the factor is aging and the level is short-term aging. This is because in Table 1, in the first evaluation scheme, the aging effect is short-term aging, so X 22 The value is 1; other levels of aging effect X 41 , X 43 The value is 0. The fifth 1 is X 52 , indicating that the factor is dry / water environment, and the level is water. This is because in Table 1, in the first evaluation scheme, the dry / water environment takes water, X 52 The value is, dry / water other level X 51 The value is 0.

[0106]

[0107] S42. Constructing multivariate linear equations

[0108] y=XA (1)

[0109] Where: the constant vector y is the pull-out strength of the pull-out specimen prepared by each asphalt-aggregate interface pull-out strength evaluation scheme; A is the correlation coefficient of the sample matrix, which is also the constant term X0 and each level X of multiple factors. ij The corresponding utility value a i A column vector consisting of ; i is the number of factors.

[0110] Preferably, referring to Table 2, the constant vector y is (2.23, 2.06, 3.21, 3.26, 3.92, 1.81, 2.01, 2.79, 3.13, 3.61, 1.71, 2.22, 2.85, 2.84, 3.11, 1.73, 2.31, 2.37, 2.64, 2.82, 1.71, 1.75, 2.26, 2.56, 3.32).

[0111] S43, transform formula (1) to calculate the correlation coefficient A of the sample matrix

[0112] A=(X T X) -1 X T y (2)

[0113] Substitute the sample matrix in step S41 and the constant vector y in step S42 into formula (2) to calculate the correlation coefficient A, see Table 3, which is also the utility value a corresponding to the constant term X0 and each level of multiple factors. i A column vector consisting of ; i is the number of factors.

[0114] S44. Calculate the importance value I of each factor i

[0115] According to the correlation coefficient A calculated in step S43, the importance value I of each factor is calculated using the following formula: i ;

[0116] I i =|a imax -a imin | (3)

[0117] Where: a imax is the utility value a corresponding to each level under the i-th factor i The maximum value of a imin is the utility value a of each level under the i-th factor i The minimum value of .

[0118] Preferably, the utility value a corresponding to each level under the i-th factor i The maximum values ​​are 0.367, 0.023, 0.422, 0.138 and 0.513 respectively; the utility value a corresponding to each level under the i-th factor i The maximum values ​​are -0.249, -0.023, -0.289, -0.191 and -0.513 respectively.

[0119] Finally, the corresponding importance values ​​of the five factors were determined, namely I1 to I5, which are 0.616, 0.046, 0.711, 0.329 and 1.026 respectively.

[0120] S45. Calculate the importance of each factor F i

[0121] According to the importance value I in step S44 i Calculate the importance of each factor F i , the calculation formula is as follows:

[0122]

[0123] Where: n is the maximum value of factor i, which is a positive integer.

[0124] In this embodiment, I1-I5 of 0.616, 0.046, 0.711, 0.329 and 1.026 are substituted into formula (4) to calculate the importance F1, F2, F3, F4 and F5 corresponding to the five factors. For details, see Table 3.

[0125] Table 3 Importance analysis table

[0126]

[0127]

[0128] S46. Comprehensive evaluation

[0129] The importance of the above calculation F i The sizes of the factors are ranked to determine the importance of the factors affecting the asphalt-aggregate interface bond strength.

[0130] According to Table 4, the utility value of each factor level on the interface bonding strength can be obtained. i When >0, it indicates that the level is positively correlated with the bond strength. The corresponding conditions are asphalt film thickness of 0.1mm and 0.2mm, asphalt type of 70# asphalt, aggregate type of sodium feldspar, aging effect of short-term aging or no aging, and in a dry environment, the utility values ​​of these levels are positive.

[0131] Furthermore, the reliability and accuracy of the comprehensive evaluation method of factors affecting the asphalt-aggregate interface bonding strength provided by the present invention are verified.

[0132] Verification 1

[0133] The calculation errors of the multivariate linear equation, correlation coefficient calculation formula and importance value calculation formula constructed by the present invention are mainly analyzed.

[0134] In the embodiment, the sample matrix X and the constant vector y are (2.23, 2.06, 3.21, 3.26, 3.92, 1.81, 2.01, 2.79, 3.13, 3.61, 1.71, 2.22, 2.85, 2.84, 3.11, 1.73, 2.31, 2.37, 2.64, 2.82, 1.71, 1.75, 2.26, 2.56, 3.32).

[0135] Substituting into formula (2), the least squares method is used to estimate the unknown vector A of the multivariate linear regression equation, and the estimated value of the correlation coefficient A is calculated:

[0136] After calculation, the least squares estimate

[0137] Referring to formula (1), the estimated value Substitution Calculate the estimated pull-out strength Calculation can be obtained Obtain an estimate of the pull-out strength for each evaluation scenario Next, the goodness of fit of the regression model is evaluated based on the estimated values ​​obtained above.

[0138] (1) The standard error SE is calculated as follows:

[0139]

[0140] Where:

[0141] RSS is the regression sum of squares

[0142] n is the sample size;

[0143] k is the number of independent variables;

[0144] is the estimated value of the pull-out strength under the i-th evaluation scheme; i ranges from 1 to 25;

[0145] It is the average value of the pull-out strength test values ​​corresponding to the 25 evaluation schemes.

[0146] Preferably, according to Table 2, It is 2.57MPa.

[0147] (2) Model significance analysis

[0148] The t value is calculated according to the following formula:

[0149]

[0150] The F value is calculated according to the following formula:

[0151]

[0152] Where: ESS is the residual sum of squares

[0153] y i is the test value of the pull-out strength under the ith evaluation scheme; see Table 2 for details.

[0154] Calculate R according to the following formula 2

[0155]

[0156] Where: TSS is the total sum of squares Adjust R according to the following formula 2

[0157]

[0158] (3) Pearson's R and Kendall's tau indicators were used to evaluate the correctness of the joint analysis model. The calculation formula of Pearson's correlation coefficient is as follows:

[0159]

[0160] In the formula, is the estimated value of the pull-out strength under the i-th evaluation scheme; y i is the test value of the pull-out strength under the i-th evaluation scheme, is the average value of the pull-out strength test values ​​corresponding to the 25 evaluation schemes, and the result is 2.57MPa; It is the average value of the estimated pull-out strength corresponding to the 25 evaluation schemes.

[0161] The Kendall correlation coefficient calculation formula is as follows:

[0162]

[0163] Where: C is the number of consistent pairs in the sample pairs (i.e., y i >y j and The logarithm of the data, or y i <y j and The number of data pairs); D is the number of inconsistent pairs in the sample pairs.

[0164] y j It is expressed as the test value of the pull-out strength under the jth evaluation scheme; It is expressed as the estimated value of the pull-out strength under the jth evaluation scheme.

[0165] Specifically, the test value of the pull-out strength y5 (3.92) > y6 (1.81), the estimated value of the pull-out strength The pair is marked as identical, C increases by 1; the test value of the pull-out strength is y 19 (2.64)<y 20 (2.82), estimated value of pull-out strength It is marked as an inconsistent pair and D increases by 1.

[0166] After calculation, the values ​​of Pearson's R and Kendall's tau were 0.996 and 0.959 respectively. The total sum of squares TSS, residual sum of squares ESS, and regression sum of squares RSS were 9.67, 1.24, and 11.12 respectively. The obtained regression coefficients, standard errors, t values, and R 2 , adjust R 2 , F values ​​are shown in Table 4.

[0167] Table 4 Results analysis table

[0168]

[0169]

[0170] See Table 4. After calculation, the F value is 357.78, with a significance of <0.01, which is significant at the level of α=0.05. Therefore, the constructed calculation model fully meets the accuracy requirements. 2 , Pearson correlation coefficient, and Kendall correlation coefficient are all close to 1, indicating that the constructed calculation model has high accuracy.

[0171] Verification 2

[0172] In order to verify the accuracy of the importance analysis of each factor in the joint analysis, the pull-out test was re-conducted, and the level of influencing factors with positive utility values ​​was selected for the experiment, that is, the utility value a in Table 3 i Factor levels greater than 0.

[0173] The asphalt types are 70# asphalt and 90# asphalt, the asphalt film thickness is 0.1mm and 0.2mm, the aggregate type is sodium feldspar, the aging effect is unaged and short-term aging, and the dry / water environment is the dry environment. Then, the orthogonal test is used to design the composition scheme of the asphalt-aggregate interface bond strength, and the optimal ratio design table of each factor level that is positively correlated with the asphalt-aggregate interface bond strength is obtained, as shown in Table 5.

[0174] For the design schemes in Table 5, pull-out specimens were made by referring to the method of the embodiment, and the pull-out strength values ​​of the pull-out specimens under various design schemes were tested, as shown in Table 5.

[0175] Table 5 Optimal ratio design table

[0176] Serial number Asphalt film thickness Asphalt Type Aggregate Type Aging Effects Dry / water environment Pull-out strength value / MPa 1 0.1mm 70# Sodium feldspar Not aged dry 3.87 2 0.1mm 70# Sodium feldspar Short-term aging dry 4.04 3 0.1mm 90# Sodium feldspar Not aged dry 3.81 4 0.1mm 90# Sodium feldspar Short-term aging dry 3.92 5 0.2mm 70# Sodium feldspar Not aged dry 3.61 6 0.2mm 70# Sodium feldspar Short-term aging dry 3.71 7 0.2mm 90# Sodium feldspar Not aged dry 3.53 8 0.2mm 90# Sodium feldspar Short-term aging dry 3.68

[0177] As can be seen from Table 5, the pull-out strength corresponding to the asphalt film thickness of 0.1mm, the aggregate type is sodium feldspar, the aging effect is short-term aging, the dry environment and the asphalt type is 70# (serial number 2) is 4.04MPa; the pull-out strength corresponding to the asphalt film thickness of 0.1mm, the aggregate type is sodium feldspar, the aging effect is short-term aging, the dry environment and the asphalt type is 90# (serial number 4) is 3.92MPa. After comparison, the pull-out strengths corresponding to serial numbers 2 and 4 are relatively close, but the bonding strength when the asphalt type is 70# is slightly greater than the bonding strength when the asphalt type is 90#. This result is consistent with the utility value a in Table 3. i The trend of change is consistent, that is, the utility value corresponding to the asphalt type factor is the smallest, and the utility value of 70# asphalt is greater than that of 90# asphalt. This further verifies the reliability of the joint analysis model used in the present invention.

[0178] In summary, the present invention constructs an asphalt-aggregate interface pull-out strength evaluation scheme and a pull-out strength test, and then uses a joint analysis method to comprehensively evaluate the factors affecting the asphalt-aggregate interface bond strength (such as asphalt film thickness, asphalt type, aggregate type, aging effect, dry / water environment), and determines the importance of the factors affecting the asphalt-aggregate interface bond strength by the importance of the factors.

[0179] The comprehensive evaluation method provided by the present invention analyzes the relationship between the asphalt-aggregate interface bonding strength and the influencing factors, and can be used as a way to quantitatively evaluate the importance of the factors affecting the interface bonding strength. In addition, the optimal ratio design of the asphalt-aggregate interface bonding strength can be screened according to the calculated utility values ​​of each factor level, so as to determine the technical measures for asphalt-aggregate mixing (aggregate type is sodium feldspar, asphalt film thickness is 0.1mm, short-term aging effect is used, and it is noted that the construction should be carried out in a dry environment and the dryness of the material should be ensured), thereby enhancing the adhesion performance between the asphalt-aggregate interface, which is of great significance to improving the service life of the asphalt pavement.

[0180] An embodiment of the present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the computer program is loaded into the processor, the method for comprehensively evaluating factors affecting the asphalt-aggregate interface bonding strength as described in any one of the preceding items is implemented.

[0181] An embodiment of the present invention further provides a storage medium storing a computer program, wherein the computer program, when executed by a processor, implements any one of the methods for comprehensively evaluating factors affecting asphalt-aggregate interface bonding strength.

Claims

1. A comprehensive evaluation method for factors affecting asphalt-aggregate interface bonding strength, characterized in that: The following steps are involved: (1) Collect and screen historical data on factors affecting the asphalt-aggregate interface bond strength, and establish an asphalt-aggregate interface pull-out strength evaluation system; (2) The aggregate is pretreated as follows to prepare asphalt-aggregate interface pull-out specimens; (3) setting the pulling rate and testing the pulling strength corresponding to a plurality of pulling specimens; (4) Use the combined analysis method to comprehensively evaluate the pull-out strength.

2. A comprehensive evaluation method for factors affecting asphalt-aggregate interface bonding strength according to claim 1, characterized in that: Step (1) is as follows: collect historical data on factors affecting the asphalt-aggregate interface bonding strength, screen out factors that have a significant impact on the asphalt-aggregate interface bonding strength, and take multiple levels for each factor; use orthogonal experiments to construct multiple asphalt-aggregate interface tensile strength evaluation systems.

3. A comprehensive evaluation method for factors affecting asphalt-aggregate interface bonding strength according to claim 2, characterized in that: In step (1), the historical data of factors affecting the asphalt-aggregate interface bonding strength include: asphalt film thickness, asphalt type, aggregate type, aging effect, and dry or wet environment.

4. A comprehensive evaluation method for factors affecting asphalt-aggregate interface bonding strength according to claim 3, characterized in that: In step (1), the thickness of the asphalt film is 0.1 mm-0.8 mm; the type of asphalt is 70#-90#; the type of aggregate is quartz, calcite, and albite; and the aging effect is unaged, short-term aged, and long-term aged.

5. The method for comprehensive evaluation of factors affecting asphalt-aggregate interface bonding strength according to claim 1, characterized in that: The pretreatment of step (2) is as follows: the surface of the aggregate is cut and polished until the surface is flat, cleaned, dried, and then polished with 220-mesh sandpaper; after polishing, the surface of the aggregate is cleaned and dried, and then cooled to room temperature after drying.

6. A comprehensive evaluation method for factors affecting asphalt-aggregate interface bonding strength according to claim 5, characterized in that: The drying temperature is 80℃±5℃, and the drying time is 1h~2h.

7. A comprehensive evaluation method for factors affecting asphalt-aggregate interface bonding strength according to claim 4, characterized in that: In step (2), when preparing the drawing specimen, the short-term aging of the asphalt is as follows: the temperature of the rotary thin film oven is set to 163°C ± 0.5°C, and preheated for not less than 16 hours; then 35g ± 0.5g of asphalt is added, and the asphalt is placed in the rotary thin film oven for 85 minutes to complete the short-term aging of the asphalt; Long-term aging of asphalt is as follows: short-term aged asphalt is placed in a pressure aging test instrument for 20h±10min at a temperature of 90-110℃ and a pressure of 2.1MPa to complete the long-term aging of asphalt; The water environment is as follows: the asphalt-aggregate specimens prepared according to the asphalt type, asphalt film thickness, aggregate type and aging effect are first placed at room temperature for 1 hour; then the asphalt-aggregate specimens are completely immersed in a water bath at 60±1℃ for 24 hours, and finally placed in a dry environment for 1 hour to room temperature.

8. The method for comprehensive evaluation of factors affecting asphalt-aggregate interface bonding strength according to claim 1, characterized in that: Step (4) comprises the following steps: (41) Constructing a sample matrix X: Constructing a sample matrix X according to the evaluation system in step (1), wherein each column of the sample matrix X represents an evaluation system for the tensile strength of the asphalt-aggregate interface; each row of the sample matrix X consists of (X0, ..., X ij )composition; Among them: X0 is a constant term, which is 1; i is the number of factors, j is the number of levels for each factor, and X ij Is the influencing factor i taking the jth level, if yes then X ij The value is 1, otherwise X ij The value is 0; (42)Construct multivariate linear equation: y=XA (1) Among them, the constant vector y is the pull-out strength corresponding to the pull-out specimen prepared by each asphalt-aggregate interface pull-out strength evaluation scheme; A is the correlation coefficient of the sample matrix, which is also the utility value a corresponding to each level of the constant term and multiple factors. i The column vector is composed of; i is the number of factors; Transform formula (1) to calculate the correlation coefficient A of the sample matrix A=(X T X) -1 X T y (2) (43) Calculate the importance value I of each factor i : According to the calculated correlation coefficient A, the importance value I of each factor is calculated using the following formula i ; I i =|a imax -a imin | (3) Among them, a imax is the utility value a corresponding to each level under the i-th factor i The maximum value of a imin is the utility value a corresponding to each level under the i-th factor i The minimum value of (44) Calculate the importance of each factor F i According to the importance value I i Calculate the importance of each factor F i , the calculation formula is as follows: Where: n is the maximum value of factor i, which is a positive integer; (45) Comprehensive evaluation: importance of calculation F i The sizes of the factors are ranked to determine the importance of the factors affecting the asphalt-aggregate interface bond strength.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the computer program is loaded into the processor, a comprehensive evaluation method for factors affecting asphalt-aggregate interface bonding strength according to any one of claims 1 to 8 is implemented.

10. A storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, a comprehensive evaluation method for factors affecting asphalt-aggregate interface bonding strength according to any one of claims 1-8 is implemented.

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