A method for predicting the fatigue life of recycled asphalt based on activation energy

Abstract

This invention discloses a method for predicting the fatigue life of recycled asphalt based on activation energy, comprising: analyzing the aging kinetic characteristics of new and old asphalt to obtain the aging activation energy E of new and old asphalt. acr_新 E acr_旧 DSR fatigue tests were performed on new asphalt to establish a fatigue damage model φ. V (N)=aN b The fatigue damage rate when new asphalt is completely destroyed is calculated, and the fatigue life of recycled asphalt is predicted based on the mass percentage of old asphalt in the recycled asphalt. This invention quantifies the influence of the incorporation of old asphalt on the fatigue damage behavior of new asphalt, and can more accurately and effectively evaluate the fatigue performance of recycled asphalt.

Description

Technical Field

[0001] This invention relates to the field of asphalt fatigue performance evaluation, and in particular to a method for predicting the fatigue life of recycled asphalt based on activation energy. Background Technology

[0002] Efficiently utilizing the large amount of reclaimed asphalt pavement (RAP) generated during highway maintenance is one of the key issues in promoting the green and low-carbon development of road engineering in my country. Road recycling technology refers to mixing RAP with new asphalt and new aggregates in a certain proportion to obtain a recycled mixture that can be used for road paving. However, the presence of old asphalt on the RAP surface affects the performance of the recycled asphalt mixture, which greatly limits the utilization efficiency of RAP.

[0003] The old asphalt on the surface of RAP (Recycled Asphalt Pavement) has hardened and become brittle primarily due to aging. Although the addition of new asphalt can soften, blend, and regenerate the aged asphalt, it cannot completely restore the performance of the old asphalt. Consequently, recycled asphalt, a mixture of new and old asphalt, is more prone to fatigue cracking under the combined effects of long-term repeated loading and environmental factors (such as sunlight and rain), thus affecting the overall service performance of recycled asphalt pavements. Therefore, a reasonable and accurate evaluation of the fatigue performance of recycled asphalt is of great significance for understanding the fatigue damage process of recycled asphalt and for seeking suitable design methods for the composition of recycled materials.

[0004] Fatigue life is a crucial indicator for evaluating the fatigue performance of asphalt, typically represented by the total number of cyclic loads required for fatigue damage to develop until failure. Fatigue life prediction models can reveal the evolution of fatigue damage in materials, providing effective support for improving the performance of materials in practical engineering applications. However, existing research has the following shortcomings:

[0005] Existing asphalt fatigue models do not consider the aging kinetics of materials. Traditional fatigue life characterization methods mostly employ empirical or mechanical models. Empirical models primarily obtain the relationship between the number of cyclic loadings and test conditions (such as strain levels) through fatigue tests, while mechanical models quantify the asphalt fatigue process by incorporating damage or fracture mechanics theories. It is worth noting that aging is one of the main causes of reduced material fatigue life, and the response rates and degrees of aging to new and used asphalt are not entirely the same; that is, their aging kinetics differ, which directly affects the development of fatigue damage behavior in recycled asphalt. Existing fatigue life characterization methods fail to consider the differences in aging resistance between new and used asphalt and their impact on the fatigue damage characteristics of recycled asphalt, and therefore cannot provide scientific and effective guidance for the design of recycled asphalt materials in practical engineering applications.

[0006] The determination of the blending ratio of new and recycled asphalt is generally achieved through trial and error. Due to the presence of recycled asphalt, the proportion of reclaimed asphalt (RAP) used is significantly limited. To obtain recycled asphalt materials that meet the requirements of actual engineering projects, several groups of recycled asphalt are typically prepared by mixing the extracted recycled asphalt with new asphalt in different proportions, and then subjected to fatigue tests on a dynamic shear rheometer (DSR). On the one hand, the required amount of recycled asphalt is large, and the commonly used extraction test requires dissolving the RAP with trichloroethylene before recovering the recycled asphalt using the Absen method. During this process, human factors inevitably lead to the residue of a small amount of trichloroethylene or secondary aging of the recycled asphalt, resulting in differences in its performance. On the other hand, the fatigue life of asphalt can typically reach tens of thousands or even hundreds of thousands of cycles, making the entire testing process time-consuming. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention proposes a method for predicting the fatigue life of recycled asphalt based on activation energy.

[0008] The specific technical solution is as follows:

[0009] A method for predicting the fatigue life of recycled asphalt based on activation energy includes the following steps:

[0010] S1: Analyze the aging kinetics of new and old asphalt to obtain the aging activation energy E of new asphalt. acr_新 The aging activation energy E of old asphalt acr_旧 ;

[0011] S2: Conduct DSR fatigue tests on new asphalt, calculate the damage density based on the shear modulus, and fit the data to obtain the damage density φ of the new asphalt under the Nth cycle of loading. V The relationship between (N) and the number of cyclic loads N is expressed by the expression φ. V (N)=aN b a and b are fitting coefficients; calculate the fatigue damage rate when the new asphalt is completely destroyed. The expression is as follows:

[0012]

[0013] In the formula, N fv Indicates the fatigue life of new asphalt;

[0014] S3: Recycled asphalt is obtained by mixing new and old asphalt. The fatigue life N of the recycled asphalt is predicted according to the following formula. fR :

[0015]

[0016] In the formula, m represents the mass percentage of old asphalt in the recycled asphalt.

[0017] Furthermore, S1 is specifically implemented through the following sub-steps:

[0018] S1.1: Prepare multiple groups of new asphalt samples and age them at different temperatures T. a Different aging durations t a Aging tests were conducted to obtain new asphalt samples under different aging conditions; multiple groups of old asphalt samples were prepared and subjected to aging at different temperatures T. a Different aging durations t a Aging tests were conducted to obtain old asphalt samples under different aging conditions.

[0019] S1.2: The carbonyl area CA of new and old asphalt samples under different aging conditions was measured using a Fourier transform infrared spectrometer.

[0020] S1.3: Calculate the change in carbonyl area of ​​new and old asphalt samples with aging time at the same aging temperature, as shown in the following expressions:

[0021] ΔCA new =CA i_new -CA 0_new

[0022] ΔCA old =CA i_old -CA 0_old

[0023] In the formula, ΔCA new ΔCA represents the change in carbonyl area before and after aging of a new asphalt sample. old This indicates the change in carbonyl area before and after aging of an old asphalt sample; CA i_new CA represents the carbonyl area measured at a certain aging time for a new asphalt sample. i_old This represents the carbonyl area measured on an old asphalt sample at a certain aging time; CA 0_new CA represents the carbonyl area measured on the original new asphalt sample. 0_old This represents the carbonyl area measured on the original old asphalt sample;

[0024] The change in carbonyl area and aging time t of new and old asphalt samples were obtained by fitting. a Relational expression:

[0025]

[0026] In the formula, ΔCA ∞_new ΔCA represents the theoretical maximum value of the carbonyl area of ​​a new asphalt sample. ∞_old This represents the theoretical maximum value of the carbonyl area of ​​the old asphalt sample; ρ cnβ represents the scaling factor along the aging time in the new asphalt aging model. cn ρ represents the dimensionless carbonyl area change rate in the new asphalt aging model; co β represents the scaling factor along the aging time in the old asphalt aging model. co This represents the dimensionless carbonyl area change rate in the old asphalt aging model;

[0027] The aging kinetic rate constants for both new and old asphalt samples at this aging temperature are then obtained, expressed as follows:

[0028] k c_老化新 =β cn ·ΔCA ∞_new

[0029] k c_老化旧 =β co ·ΔCA ∞_old

[0030] S1.4: Based on the aging kinetic process rate constants corresponding to different aging temperatures, the relationship between the rate constant and the absolute aging temperature T is fitted. abs Relational expression:

[0031]

[0032] In the formula, A c_老化新 A represents the pre-exponential factor for the aging of new asphalt. c_老化旧 E represents the pre-exponential factor indicating the aging of old asphalt; acr_新 E represents the aging activation energy of new asphalt. acr_旧 T represents the aging activation energy of old asphalt; R represents the ideal gas constant; T represents the aging activation energy of old asphalt. abs The absolute temperature representing aging, T abs =T a +273.15.

[0033] Furthermore, S2 is specifically implemented through the following sub-steps:

[0034] S2.1: A time-scan test was conducted on new asphalt samples using a dynamic shear rheometer in strain control mode, and the test temperature and loading frequency were set, and the shear modulus obtained from the test was recorded.

[0035] S2.2: Calculate the damage density of the new asphalt sample based on the recorded shear modulus:

[0036]

[0037] In the formula, φ V (N) represents the damage density of the new asphalt under the Nth cycle of loading, with a value range of 0 to 1; This represents the shear modulus under the Nth cycle of loading. Indicates the initial shear modulus of the sample;

[0038] By fitting the damage density-cycle loading curve, the following expression is obtained:

[0039] φ V (N)=aN b

[0040] In the formula, a and b are fitting coefficients;

[0041] S2.3: Determine the damage density φ reached when the new asphalt is completely destroyed. max The expression is as follows:

[0042]

[0043] In the formula, φ max ρ represents the theoretical maximum value of the damaged density of new asphalt. d β represents the scaling factor along the number of cyclic loads. d This represents the dimensionless rate of change of damage density.

[0044] When the new asphalt is completely destroyed, that is, when the damaged density of the new asphalt reaches φ max At that time, the corresponding fatigue damage rate expression is as follows:

[0045]

[0046] In the formula, N fV This indicates the fatigue life of new asphalt.

[0047] Furthermore, the new asphalt sample is made of #70 base asphalt, denoted as 70-A, and SBS modified asphalt is also selected, denoted as SBS-MA; the old asphalt sample is aged #70 base asphalt and aged SBS modified asphalt prepared according to the standards of film heating test and pressure aging vessel accelerated aging test, respectively. The aged #70 base asphalt is denoted as PA, and the aged SBS modified asphalt is denoted as PB.

[0048] Furthermore, in S2, the parameters for the DSR fatigue test are set as follows: a 5% strain level is applied to 70-A, the test temperature is 25℃, the loading frequency is 10Hz, and 70-A is kept at the test temperature for 15min before the test begins; a 10% strain level is applied to SBS-MA, the test temperature is 25℃, the loading frequency is 10Hz, and 70-A is kept at the test temperature for 15min before the test begins.

[0049] The beneficial effects of this invention are:

[0050] (1) The method of the present invention takes into full account the difference in aging resistance between new and old asphalt from the perspective of aging kinetics, quantifies the influence of the incorporation of old asphalt on the fatigue damage behavior of new asphalt, and establishes a fatigue life characterization method, revealing the intrinsic relationship between material fatigue damage characteristics and aging, and can more accurately and effectively evaluate the fatigue performance of recycled asphalt.

[0051] (2) The method of the present invention can also determine the mixing ratio of new and old asphalt according to the actual fatigue life required by the recycled asphalt, which greatly reduces the time and manpower costs required by the traditional trial and error method, significantly reduces the cumbersome test process, avoids interference from various factors, reduces errors in the test process, and helps to improve the utilization efficiency of old asphalt and promote the high-quality development of recycled asphalt pavement technology. Attached Figure Description

[0052] Figure 1 This is a flowchart of the fatigue life prediction method for recycled asphalt based on activation energy proposed in an embodiment of the present invention.

[0053] Figure 2 This is a flowchart of the method for obtaining the aging activation energy of new and old asphalt in an embodiment of the present invention.

[0054] Figure 3 This is a flowchart of a method for obtaining the fatigue damage rate when a new asphalt sample is completely destroyed, as described in an embodiment of the present invention.

[0055] Figure 4 This is a schematic diagram comparing the predicted fatigue life and the measured fatigue life of recycled asphalt in an embodiment of the present invention. Detailed Implementation

[0056] The present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments. The objectives and effects of the present invention will become clearer as a result. The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0057] like Figure 1 As shown, a method for predicting the fatigue life of recycled asphalt based on activation energy specifically includes the following steps:

[0058] S1: Analyze the aging kinetics of new and old asphalt to obtain the aging activation energy E of new asphalt. acr_新 The aging activation energy E of old asphalt acr_旧 ,like Figure 2 As shown, this is achieved through the following sub-steps:

[0059] S1.1: Prepare multiple groups of new asphalt samples and place them in pressure aging containers, aging them at different temperatures T. aDifferent aging durations t a Aging tests were conducted to obtain new asphalt samples under different aging conditions; multiple groups of old asphalt samples were prepared and placed in pressure aging containers, and subjected to different aging temperatures T. a Different aging durations t a Aging tests were conducted to obtain old asphalt samples under different aging conditions. In this embodiment, the aging temperature T... a The aging time is t at 90℃, 100℃, or 110℃. a Nine groups of new asphalt samples with different aging temperatures and durations were collected, with aging times of 10h, 20h, or 40h, and nine groups of old asphalt samples with different aging temperatures and durations.

[0060] S1.2: Place new asphalt samples and old asphalt samples under different aging conditions in a Fourier transform infrared spectrometer to measure the carbonyl area CA.

[0061] S1.3: Calculate the change in carbonyl area of ​​new and old asphalt samples with aging time at the same aging temperature, as shown in the following expressions:

[0062] ΔCA new =CA i_new -CA 0_new

[0063] ΔCA old =CA i_old -CA 0_old

[0064] In the formula, ΔCA new ΔCA represents the change in carbonyl area before and after aging of a new asphalt sample. old This indicates the change in carbonyl area before and after aging of an old asphalt sample; CA i_new CA represents the carbonyl area measured at a certain aging time for a new asphalt sample. i_old This represents the carbonyl area measured on an old asphalt sample at a certain aging time; CA 0_new CA represents the carbonyl area measured on the original new asphalt sample. 0_old This represents the carbonyl area measured on the original old asphalt sample.

[0065] The change in carbonyl area and aging time t of new and old asphalt samples were obtained by fitting. a The relationship curve is expressed as follows:

[0066]

[0067] In the formula, ΔCA ∞_new ΔCA represents the theoretical maximum value of the carbonyl area of ​​a new asphalt sample. ∞_oldThis represents the theoretical maximum value of the carbonyl area of ​​the old asphalt sample; ρ cn β represents the scaling factor along the aging time in the new asphalt aging model. cn ρ represents the dimensionless carbonyl area change rate in the new asphalt aging model; co β represents the scaling factor along the aging time in the old asphalt aging model. co This represents the dimensionless carbonyl area change rate in the old asphalt aging model.

[0068] The aging kinetic rate constants for both new and old asphalt samples at this aging temperature are then obtained, expressed as follows:

[0069] k c_老化新 =β cr ·ΔCA ∞_new

[0070] k c_老化旧 =β cr ·ΔCA ∞_old

[0071] S1.4: Obtain the aging kinetic process rate constants corresponding to different aging temperatures using the method in S1.3, and fit the rate constants to the absolute aging temperature T. abs The relationship curve is expressed as follows:

[0072]

[0073] In the formula, A c_老化新 A represents the pre-exponential factor for the aging of new asphalt. c_老化旧 The pre-exponential factors representing the aging of old asphalt were all obtained through fitting; E acr_新 E represents the aging activation energy of new asphalt. acr_旧 The aging activation energy of old asphalt is expressed in kJ / mol and obtained through fitting; R represents the ideal gas constant in J / mol / K, which is a known quantity; T abs The absolute temperature representing aging, T abs =T a +273.15, in units of K, is a known quantity.

[0074] Based on the relationship between the rate constant of the aging kinetic process and the absolute temperature of the aging reaction, the activation energy E of new asphalt for aging is obtained. acr_新 The aging activation energy E of old asphalt acr_旧 .

[0075] S2: Conduct DSR fatigue tests on new asphalt, establish a fatigue damage model and determine its parameters, thereby obtaining the fatigue damage rate when the new asphalt sample is completely destroyed, such as... Figure 3 As shown, this is achieved through the following sub-steps:

[0076] S2.1: A dynamic shear rheometer was used to conduct a time-scan test on the new asphalt sample in strain control mode. The test temperature and loading frequency were set, and the shear modulus obtained from the test was recorded.

[0077] S2.2: Calculate the damage density of the new asphalt sample based on the recorded shear modulus:

[0078]

[0079] In the formula, N represents the number of cyclic loads, and φ V (N) represents the damage density of the new asphalt under the Nth cycle of loading, with a value range of 0 to 1; This represents the shear modulus under the Nth cycle of loading, in kPa. This indicates the initial shear modulus of the sample, expressed in kPa.

[0080] By fitting the damage density-cycle loading curve, the relationship between the two is obtained as follows:

[0081] φ V (N)=aN b

[0082] In the formula, a and b are fitting coefficients.

[0083] S2.3: Use the following formula to fit the damage density-cycle loading curve to determine the damage density φ reached when the new asphalt is completely destroyed. max :

[0084]

[0085] In the formula, φ max ρ represents the theoretical maximum value of the damaged density of new asphalt. d β represents the scaling factor along the number of cyclic loads. d This represents the dimensionless rate of change of damage density.

[0086] When the new asphalt is completely destroyed (i.e., the damage density reaches φ) max When the fatigue damage rate is 100%, the corresponding fatigue damage rate can be calculated using the following formula:

[0087]

[0088] In the formula, N fV This indicates the fatigue life of new asphalt.

[0089] S3: Establish the fatigue damage rate expression when recycled asphalt is completely destroyed and calculate the fatigue life. The specific steps are as follows:

[0090] Recycled asphalt is obtained by mixing new asphalt and old asphalt in a certain proportion, and the E determined by S1 is... acr_新 E acr_旧 Substituting the new asphalt fatigue damage rate determined by S2 into the following formula:

[0091]

[0092] In the formula, The value of N represents the fatigue damage rate when the recycled asphalt is completely destroyed; m represents the mass percentage of old asphalt in the recycled asphalt, which can be set according to actual needs. fR This indicates the fatigue life of recycled asphalt.

[0093] The fatigue life prediction model for recycled asphalt is obtained, and its expression is as follows:

[0094]

[0095] The present invention will be specifically described below through the following embodiments.

[0096] Example 1

[0097] S1: In this embodiment, the new asphalt samples are made of #70 base asphalt (70-A) and SBS modified asphalt (SBS-MA). The aged #70 base asphalt (hereinafter referred to as PA) and aged SBS modified asphalt (hereinafter referred to as PB) are prepared according to the standards of film heating test and pressure aging vessel accelerated aging test, respectively. These are the old asphalt samples.

[0098] The four types of asphalt samples were poured into stainless steel pans that met the thin film heating standard and placed in pressure aging containers for aging at different degrees. The specific aging conditions are shown in Table 1.

[0099] Table 1 Asphalt Aging Test Scheme

[0100]

[0101] Asphalt samples aged at different aging temperatures and times as shown in Table 1 were taken out and subjected to Fourier transform infrared spectroscopy (FTIR) tests. The infrared spectra of each asphalt sample were analyzed, with wavenumbers ranging from 1650 to 1820 cm⁻¹. -1 It is the carbonyl C=O absorption peak.

[0102] The final calculated aging activation energy indices for the four asphalt samples were 70-A:E acr_新1 = 54.75 kJ / mol, SBS-MA: E acr_新2 = 66.04 kJ / mol; PA: E acr_旧1 =113.14 kJ / mol, PB:E acr_旧2 = 89.46 kJ / mol.

[0103] S2: DSR was used to conduct time-scan tests under strain control mode on 70-A and SBS-MA asphalt samples respectively. The strain level applied to 70-A was 5% and the strain level applied to SBS-MA was 10%. The test temperature was 25℃ and the loading frequency was 10Hz. Before the test, the new asphalt samples were kept at the test temperature for 15min. After the test started, parameters such as shear modulus and phase angle were recorded.

[0104] In this embodiment, the fatigue damage model expressions for 70-A and SBS-MA are as follows:

[0105] 70-A: φ(N)=0.0054N 0.4698

[0106] SBS-MA: φ(N)=0.0224N 0.2680

[0107] When the new asphalt sample was completely destroyed, the fatigue damage rate corresponding to 70-A was 7.52E-06, and the fatigue damage rate corresponding to SBS-MA was 1.62E-06.

[0108] S3: Recycled asphalt prepared by mixing new and old asphalt in different proportions. The recycling scheme is shown in Table 2.

[0109] Table 2 Types of Recycled Asphalt

[0110] serial number Old asphalt type New types of asphalt Quality of old asphalt: Quality of new asphalt RA11 PA 70-A 1:1 RA21 PA 70-A 2:1 RB11 PB SBS-MA 1:1 RB21 PB SBS-MA 2:1

[0111] Specifically, when preparing recycled asphalt samples, the heating and stirring temperature was 150℃, the stirring rate was 1500 r / min, and the stirring time was 30 min.

[0112] According to the formula, the predicted fatigue life of recycled asphalt is:

[0113] RA11:38988. RA21:34416. RB11:63748. RB21:60535.

[0114] To verify the predictive effect of the method of the present invention, recycled asphalt was subjected to DSR fatigue tests according to the method and parameter settings of S2. The measured fatigue life was calculated and compared with the predicted fatigue life value mentioned above, and plotted as follows. Figure 4 The graph shows a comparison between the measured fatigue life and the predicted fatigue life. (From...) Figure 4 As can be seen, the data points almost coincide with the contour lines, indicating that the fatigue damage model determined by the method in this embodiment of the invention can accurately predict the fatigue life of different recycled asphalt, thus demonstrating the effectiveness of this method.

[0115] Furthermore, the method of this invention can also provide guidance on material composition design for long-life recycled asphalt, particularly in determining the blending ratio of new and used asphalt. This method can be used to calculate the ratio based on actual engineering requirements. For known fatigue life requirements, the method of this invention can also be used to calculate the mass percentage of used asphalt in the recycled asphalt, as detailed below:

[0116] Assuming that the fatigue life of the recycled asphalt obtained by mixing PB and SBS-MA is required to be 68,000 cycles (total number of cycles), according to the design method provided by this invention, by substituting into the expression for predicting the fatigue life of the recycled asphalt, the PB addition ratio (mass percentage of PB in the recycled asphalt) can be calculated to be 29%.

[0117] Assuming that the fatigue life of the recycled asphalt obtained after mixing PA and 70-A is required to be 50,000 cycles (total number of cycles), according to the design method provided by this invention, by substituting into the expression for predicting the fatigue life of the recycled asphalt, the PA addition ratio (mass percentage of PA in the recycled asphalt) can be calculated to be 19%.

[0118] It will be understood by those skilled in the art that the above descriptions are merely preferred examples of the invention and are not intended to limit the invention. Although the invention has been described in detail with reference to the foregoing examples, those skilled in the art can still modify the technical solutions described in the foregoing examples or make equivalent substitutions for some of the technical features. All modifications and equivalent substitutions made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A method for predicting the fatigue life of recycled asphalt based on activation energy, characterized in that, Includes the following steps: S1: Analyze the aging kinetics of new and old asphalt to obtain the aging activation energy E of new asphalt. acr_新 The aging activation energy E of old asphalt acr_旧 ; S2: Conduct DSR fatigue tests on new asphalt, calculate the damage density of the new asphalt sample based on the shear modulus, and fit the result to obtain the damage density φ of the new asphalt under the Nth cycle of loading. V The relationship between (N) and the number of cyclic loads N is expressed by the expression φ. V (N)=aN b a and b are fitting coefficients; calculate the fatigue damage rate when the new asphalt is completely destroyed. The expression is as follows: In the formula, N fv Indicates the fatigue life of new asphalt; S3: Recycled asphalt is obtained by mixing new and old asphalt. The fatigue life N of the recycled asphalt is predicted according to the following formula. fR : In the formula, m represents the mass percentage of old asphalt in the recycled asphalt.

2. The method for predicting the fatigue life of recycled asphalt based on activation energy according to claim 1, characterized in that, S1 is specifically implemented through the following sub-steps: S1.1: Prepare multiple groups of new asphalt samples and age them at different temperatures T. a Different aging durations t a Aging tests were conducted to obtain new asphalt samples under different aging conditions; Multiple groups of old asphalt samples were prepared and subjected to different aging temperatures T. a Different aging durations t a Aging tests were conducted to obtain old asphalt samples under different aging conditions. S1.2: The carbonyl area CA of new and old asphalt samples under different aging conditions was measured using a Fourier transform infrared spectrometer. S1.3: Calculate the change in carbonyl area of ​​new and old asphalt samples with aging time at the same aging temperature, as shown in the following expressions: ΔCA new =CA i_new -THAT 0_new ΔCA old =CA i_old -THAT 0_old In the formula, ΔCA new ΔCA represents the change in carbonyl area before and after aging of a new asphalt sample. old This indicates the change in carbonyl area before and after aging of an old asphalt sample; CA i_new CA represents the carbonyl area measured at a certain aging time for a new asphalt sample. i_old This represents the carbonyl area measured on an old asphalt sample at a certain aging time; CA 0_new CA represents the carbonyl area measured on the original new asphalt sample. 0_old This represents the carbonyl area measured on the original old asphalt sample; The change in carbonyl area and aging time t of new and old asphalt samples were obtained by fitting. a Relational expression: In the formula, ΔCA ∞_new ΔCA represents the theoretical maximum value of the carbonyl area of ​​a new asphalt sample. ∞_old This represents the theoretical maximum value of the carbonyl area of ​​the old asphalt sample; ρ cn β represents the scaling factor along the aging time in the new asphalt aging model. cn This represents the dimensionless carbonyl area change rate in the new asphalt aging model; ρ co β represents the scaling factor along the aging time in the old asphalt aging model. co This represents the dimensionless carbonyl area change rate in the old asphalt aging model; The aging kinetic rate constants for both new and old asphalt samples at this aging temperature are then obtained, expressed as follows: k c_老化新 =b cn ·ΔCA ∞_new k c_老化旧 =b co ·ΔCA ∞_old S1.4: Based on the aging kinetic process rate constants corresponding to different aging temperatures, the relationship between the rate constant and the absolute aging temperature T is fitted. abs Relational expression: In the formula, A c_老化新 A represents the pre-exponential factor for the aging of new asphalt. c_老化旧 E represents the pre-exponential factor indicating the aging of old asphalt; acr_新 E represents the aging activation energy of new asphalt. acr_旧 T represents the aging activation energy of old asphalt; R represents the ideal gas constant; T represents the aging activation energy of old asphalt. abs The absolute temperature representing aging, T abs =T a +273.

15.

3. The method for predicting the fatigue life of recycled asphalt based on activation energy according to claim 1, characterized in that, S2 is specifically implemented through the following sub-steps: S2.1: A time-scan test was conducted on new asphalt samples using a dynamic shear rheometer in strain control mode, and the test temperature and loading frequency were set, and the shear modulus obtained from the test was recorded. S2.2: Calculate the damage density of the new asphalt sample based on the recorded shear modulus: In the formula, φ V (N) represents the damage density of the new asphalt under the Nth cycle of loading, with a value range of 0 to 1; This represents the shear modulus under the Nth cycle of loading. Indicates the initial shear modulus of the sample; By fitting the damage density-cycle loading curve, the following expression is obtained: φ V (N)=aN b In the formula, a and b are fitting coefficients; S2.3: Determine the damage density φ reached when the new asphalt is completely destroyed. max The expression is as follows: In the formula, φ max ρ represents the theoretical maximum value of the damaged density of new asphalt. d β represents the scaling factor along the number of cyclic loads. d This represents the dimensionless rate of change of damage density. When the new asphalt is completely destroyed, that is, when the damaged density of the new asphalt reaches φ max At that time, the corresponding fatigue damage rate expression is as follows: In the formula, N fV This indicates the fatigue life of new asphalt.

4. The method for predicting the fatigue life of recycled asphalt based on activation energy according to claim 2, characterized in that, The new asphalt samples were made of #70 base asphalt, denoted as 70-A, and SBS modified asphalt, denoted as SBS-MA. The old asphalt samples were aged #70 base asphalt and aged SBS modified asphalt prepared according to the standards of film heating test and pressure aging vessel accelerated aging test, respectively. The aged #70 base asphalt was denoted as PA, and the aged SBS modified asphalt was denoted as PB.

5. The method for predicting the fatigue life of recycled asphalt based on activation energy according to claim 4, characterized in that, In S2, the parameters for the DSR fatigue test are set as follows: 5% strain level is applied to 70-A, the test temperature is 25℃, the loading frequency is 10Hz, and 70-A is kept at the test temperature for 15min before the test begins; 10% strain level is applied to SBS-MA, the test temperature is 25℃, the loading frequency is 10Hz, and 70-A is kept at the test temperature for 15min before the test begins.

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