Asphalt aging degree detection method for asphalt mixture thermal recycling

Abstract

The invention relates to the technical field of material testing, in particular to an asphalt aging degree detection method for thermal recycling of an asphalt mixture, which comprises the following steps: acquiring asphalt samples in the same batch, detecting the asphalt samples by using a dynamic shear rheometer at different testing temperatures, acquiring the physical aging performance of the asphalt in the same batch, and determining the aging degree of the asphalt in the asphalt mixture. And obtaining the internal chemical aging performance of the same batch of asphalt by combining the difference between the absorption peak intensity of each functional group in the first functional group and the second functional group of each asphalt sample and the corresponding standard absorption peak intensity, and obtaining the comprehensive aging performance of the same batch of asphalt by fusing the asphalt physical aging performance and the asphalt internal chemical aging performance. Therefore, the problems of incomplete and inaccurate analysis and the like caused by a single method are avoided, the aging characteristics of the asphalt can be deeply analyzed from two aspects of physics and chemistry, and the aging degree of the asphalt can be accurately and comprehensively obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of material testing, and in particular to a method for detecting the degree of asphalt aging used for thermal recycling of asphalt mixtures. Background Art

[0002] Thermal recycling of asphalt mixtures involves regenerating aged asphalt mixtures through thermal regeneration technology, restoring their properties and enabling their reuse in road construction and maintenance. One of the core challenges of this process is accurately assessing the degree of asphalt aging. Aged asphalt degrades performance, affecting the quality of the recycled mixture. Therefore, determining the degree of aging is crucial for determining the dosage of regenerants and process parameters, ensuring that the recycled asphalt mixture meets performance requirements.

[0003] Current asphalt aging testing typically uses a dynamic shear rheometer (DSR) to measure asphalt's rheological properties, understanding its elasticity and fluidity at different temperatures, thereby revealing the asphalt's aging degree. However, asphalt aging occurs in distinct stages and is a non-uniform process. Especially during road use, the degree of aging is affected by a variety of factors (such as traffic load, temperature fluctuations, and moisture). Dynamic shear rheometer testing alone only provides macroscopic physical properties of aged asphalt, and therefore cannot accurately and comprehensively assess the asphalt's aging degree. Summary of the Invention

[0004] In order to solve the technical problem that existing asphalt aging degree detection methods cannot accurately and comprehensively obtain the asphalt aging degree, the purpose of the present invention is to provide an asphalt aging degree detection method for hot recycling of asphalt mixtures. The technical solution adopted is as follows:

[0005] In a first aspect of the present invention, a method for detecting the degree of asphalt aging for thermal recycling of asphalt mixture is provided, comprising:

[0006] Obtain samples of various asphalts from the same batch;

[0007] At different test temperatures, each asphalt sample is tested using a dynamic shear rheometer to obtain the physical aging performance of the asphalt of the same batch;

[0008] Obtaining a first functional group and a second functional group of each asphalt sample, wherein the first functional group is a functional group with an increased absorption peak intensity, and the second functional group is a functional group with a decreased absorption peak intensity;

[0009] Obtaining the internal chemical aging performance of the same batch of asphalt according to the difference between the absorption peak intensity of each functional group in the first functional group and the second functional group and the corresponding standard absorption peak intensity;

[0010] The physical aging performance of the asphalt and the internal chemical aging performance of the asphalt are integrated to obtain the comprehensive aging performance of the asphalt of the same batch.

[0011] In an exemplary embodiment, the asphalt samples are tested using a dynamic shear rheometer at different test temperatures to obtain the physical aging performance of the asphalt of the same batch, including:

[0012] At different test temperatures, each asphalt sample was tested using a dynamic shear rheometer to obtain the initial aging performance of each asphalt sample;

[0013] According to the fluctuation of the initial aging performance of the asphalt samples in the same batch, the uneven and complex aging trend of the same batch is obtained.

[0014] In an exemplary embodiment, the asphalt samples are tested using a dynamic shear rheometer at different test temperatures to obtain the initial aging performance of each asphalt sample, including:

[0015] At different test temperatures, each asphalt sample was tested using a dynamic shear rheometer to obtain the core parameters of each asphalt sample;

[0016] Based on the differences between the core parameters of each asphalt sample and the corresponding standard core parameters at the same test temperature, the parameter change rates of the core parameters of each asphalt sample before and after aging at different test temperatures were obtained;

[0017] The effect of each test temperature on aging is used as a weight, and the parameter change rates of each core parameter of the asphalt sample before and after aging at different test temperatures are integrated to obtain the initial aging performance of the asphalt sample.

[0018] In an exemplary embodiment, using the influence of each test temperature on aging as a weight includes:

[0019] The sum of the temperatures of all the test temperatures is calculated, and the ratio of each test temperature to the sum of the temperatures is used as the weight of each test temperature.

[0020] In an exemplary embodiment, the effects of various test temperatures on aging are used as weights, and the parameter change rates of various core parameters of the asphalt sample before and after aging at different test temperatures are integrated to obtain the initial aging performance of the asphalt sample, including:

[0021] Calculate the average value of the parameter change rate of each core parameter of the asphalt sample before and after aging at each test temperature to obtain the average parameter change rate of the asphalt sample before and after aging at the test temperature;

[0022] Taking the effect of each test temperature on aging as the weight, the average change rate of the parameters of the asphalt samples before and after aging at each test temperature was weighted and summed to obtain the initial aging performance of the asphalt samples.

[0023] In an exemplary embodiment, obtaining the internal chemical aging performance of the same batch of asphalt according to the difference between the absorption peak intensity of each functional group in the first functional group and the second functional group and the corresponding standard absorption peak intensity includes:

[0024] Obtaining an absorption peak intensity difference between the absorption peak intensity of each functional group in the first functional group and the second functional group and the standard absorption peak intensity of the corresponding functional group;

[0025] The absorption peak intensity differences in the asphalt samples are integrated to obtain the internal chemical aging performance of the asphalt samples;

[0026] According to the internal chemical aging performance of all asphalt samples in the same batch, the internal chemical aging performance of the asphalt in the same batch is obtained.

[0027] In an exemplary embodiment, the absorption peak intensity difference in the fused asphalt sample is used to obtain the internal chemical aging performance of the asphalt sample, including:

[0028] Calculate the sum of the first difference and the second difference in the first asphalt sample to obtain the internal chemical aging performance of the first asphalt sample; the first asphalt sample is any asphalt sample, and the first difference is the difference in absorption peak intensity between the absorption peak intensity of each functional group in the first functional group of the first asphalt sample and the standard absorption peak intensity of the corresponding functional group; the second difference is the difference in absorption peak intensity between the absorption peak intensity of each functional group in the second functional group of the first asphalt sample and the standard absorption peak intensity of the corresponding functional group.

[0029] In an exemplary embodiment, obtaining the internal chemical aging performance of the asphalt of the same batch according to the internal chemical aging performance of all asphalt samples in the same batch includes:

[0030] The average value of the internal chemical aging performance of each asphalt sample in the same batch is calculated as the internal chemical aging performance of the asphalt in the same batch.

[0031] In an exemplary embodiment, the integration of the physical aging performance of asphalt and the internal chemical aging performance of asphalt to obtain the comprehensive aging performance of the same batch of asphalt includes:

[0032] According to the initial aging performance of each asphalt sample, the average initial aging performance of the same batch is obtained;

[0033] Obtaining an impact weight based on the uneven and complex aging trend of the same batch;

[0034] According to the influence weights, the average initial aging performance and the internal chemical aging performance of the asphalt of the same batch are weightedly summed to obtain the comprehensive aging performance of the asphalt of the same batch.

[0035] In an exemplary embodiment, the weighted sum of the average initial aging performance and the internal chemical aging performance of the asphalt of the same batch is performed according to the influence weight to obtain the comprehensive aging performance of the asphalt of the same batch, including:

[0036] Calculating the product of the internal chemical aging performance of the asphalt and the impact weight to obtain a first product;

[0037] Calculating the product of the average initial aging performance and the negative correlation weight to obtain a second product; the sum of the negative correlation weight and the impact weight is 1;

[0038] The sum of the first product and the second product is calculated as the comprehensive aging performance of the asphalt of the same batch.

[0039] The present invention has the following beneficial effects: first, a dynamic shear rheometer is used to obtain the physical aging performance of asphalt of the same batch, and then the physical complexity of the asphalt aging process is determined; then, the internal chemical aging performance of the asphalt of the same batch is obtained by combining the functional groups with increased absorption peak intensity and the functional groups with reduced absorption peak intensity of the asphalt sample with the difference in the corresponding standard absorption peak intensity; finally, the physical aging performance of asphalt and the internal chemical aging performance of asphalt are comprehensively considered to obtain the comprehensive aging performance of asphalt of the same batch. This avoids the problems of incomplete and accurate analysis brought about by a single method, and can deeply analyze the aging characteristics of asphalt from both physical and chemical levels, so as to accurately and comprehensively obtain the degree of asphalt aging. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a flow chart of a method for detecting the degree of asphalt aging for hot recycling of asphalt mixtures provided by one embodiment of the present invention;

[0041] Figure 2 This is a flowchart for obtaining the overall physical aging performance of asphalt provided by one embodiment of the present invention;

[0042] Figure 3 is a flow chart for obtaining the initial aging performance of an asphalt sample provided by one embodiment of the present invention;

[0043] Figure 4 This is a specific calculation flow chart of the initial aging performance provided by one embodiment of the present invention;

[0044] Figure 5 This is a flow chart for obtaining the internal chemical aging performance of asphalt provided by one embodiment of the present invention;

[0045] Figure 6 This is a flow chart for obtaining the comprehensive aging performance of asphalt provided by one embodiment of the present invention;

[0046] Figure 7 This is a specific calculation flow chart of the comprehensive aging performance of asphalt provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0047] To further illustrate the technical means and effects employed by the present invention to achieve its intended objectives, the following detailed description of the specific embodiments, structures, features, and effects of the present invention is provided in conjunction with the accompanying drawings and preferred embodiments. In the following description, references to "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which this invention belongs. The data and information collected in this application have been obtained with full consent and authorization, and the collection, use, and processing of relevant information must comply with the relevant laws, regulations, and standards of the relevant countries and regions.

[0049] In this embodiment, a dynamic shear rheometer is used to test multiple asphalt samples in the same batch to obtain relevant rheological property data. First, the standardization of the test conditions needs to be determined as follows: (1) Test temperature: According to the use environment and performance grade of the asphalt (such as PG grading), a suitable test temperature is selected. There are multiple test temperature settings, including high temperature and medium temperature. The number of test temperature settings and the specific temperature values ​​of each test temperature are set according to actual needs. For example, the high temperature test temperature is 68°C and the medium temperature test temperature is 24°C. (2) Frequency range: 10 rad / s (about 1.59 Hz) is usually used as the standard frequency. (3) Strain level: Ensure that the test is within the linear viscoelastic range (such as 12% strain). (4) Sample preparation: Ensure that the preparation conditions of the asphalt samples before and after aging are consistent (such as thin film oven aging RTFOT, pressure aging PAV).

[0050] like Figure 1 As shown, the present embodiment provides a method for detecting the degree of asphalt aging for hot recycling of asphalt mixture, comprising the following steps:

[0051] Step 1: Obtain asphalt samples from the same batch.

[0052] Step 2: Use a dynamic shear rheometer to test each asphalt sample at different test temperatures to obtain the physical aging performance of the same batch of asphalt.

[0053] Step 3: Obtain the first functional group and the second functional group of each asphalt sample, where the first functional group is the functional group with increased absorption peak intensity, and the second functional group is the functional group with decreased absorption peak intensity.

[0054] Step 4: The internal chemical aging performance of the same batch of asphalt is obtained based on the difference between the absorption peak intensity of each functional group in the first functional group and the second functional group and the corresponding standard absorption peak intensity.

[0055] Step 5: Combine the physical aging performance of asphalt and the internal chemical aging performance of asphalt to obtain the comprehensive aging performance of the same batch of asphalt.

[0056] The specific implementation process of each step is described below with reference to the accompanying drawings.

[0057] Step 1: Obtain asphalt samples from the same batch.

[0058] In the asphalt to be tested, multiple samples are randomly selected from the same batch (i.e., the same source) of asphalt, and these samples are used as the asphalt samples of the batch in subsequent testing. The number of asphalt samples selected is determined by actual conditions.

[0059] Step 2: Use a dynamic shear rheometer to test each asphalt sample at different test temperatures to obtain the physical aging performance of the same batch of asphalt.

[0060] Thermal recycling of asphalt mixture refers to the treatment of old asphalt with additives and other treatments to restore its performance. Chemical and physical changes will occur during the aging process of asphalt. Accurately assessing the degree of aging of asphalt can help add suitable additives to the old asphalt, namely regeneration agents, plasticizers, antioxidants, etc., to help improve the fluidity and ductility of the asphalt, and make up for the losses during the aging process of asphalt.

[0061] This step involves analyzing the physical properties of the asphalt samples. Using a dynamic shear rheometer, each asphalt sample from the same batch is tested at different test temperatures to determine the physical aging characteristics of the asphalt.

[0062] In an exemplary embodiment, Figure 2 As shown in the figure, the overall process of obtaining the physical aging performance of asphalt includes:

[0063] Step 2-1: At different test temperatures, each asphalt sample is tested using a dynamic shear rheometer to obtain the initial aging performance of each asphalt sample.

[0064] At different test temperatures, each asphalt sample is first tested using a dynamic shear rheometer to obtain the initial aging performance of each asphalt sample. In an exemplary embodiment, Figure 3 As shown in Figure 2, the process of obtaining the initial aging performance of each asphalt sample includes:

[0065] Step 2-1-1: Use a dynamic shear rheometer to test each asphalt sample at different test temperatures to obtain the core parameters of each asphalt sample.

[0066] For ease of description, the first asphalt sample is set to be any asphalt sample in the same batch, and the first test temperature is set to be any test temperature.

[0067] A dynamic shear rheometer was used to test the first asphalt sample at a first test temperature to obtain core parameters of the first asphalt sample. The core parameters of the first asphalt sample obtained by the dynamic shear rheometer are the complex shear modulus (G*) and phase angle (δ), which reflect the first asphalt sample's ability to resist shear deformation and its viscoelastic ratio, respectively.

[0068] Step 2-1-2: Based on the differences between the core parameters of each asphalt sample and the corresponding standard core parameters at the same test temperature, the parameter change rates of the core parameters of each asphalt sample before and after aging at different test temperatures are obtained.

[0069] At each test temperature, asphalt has a standard core parameter. This standard core parameter refers to the core parameter of the asphalt when it is not aged. In an exemplary embodiment, an unaged asphalt sample is obtained and tested at each test temperature using a dynamic shear rheometer. The core parameters of the unaged asphalt sample at each test temperature are obtained and defined as the standard core parameters at each test temperature. The standard core parameters include the standard complex shear modulus and the standard phase angle.

[0070] Obtain the differences between the core parameters of the first asphalt sample at the first test temperature and the core parameters of the corresponding standard at the same first test temperature. The calculation formula is as follows:

[0071] Δq l,i,t =|q l,i,t -q′ i,t |;

[0072] Where Δq l,i,trepresents the absolute value of the difference between the ith core parameter of the lth asphalt sample at the tth test temperature and the ith standard core parameter at the tth test temperature, q′ i,t represents the value of the i-th standard core parameter at the t-th test temperature, q l,i,t It represents the actual value of the i-th core parameter of the l-th asphalt sample at the t-th test temperature.

[0073] As explained above, since the core parameters include two parameters, i is 1 and 2, which are the complex shear modulus and phase angle respectively. When it is the complex shear modulus, the absolute value of the difference between the complex shear modulus and the standard complex shear modulus is calculated; when it is the phase angle, the absolute value of the difference between the phase angle and the standard phase angle is calculated.

[0074] Then, based on the differences between the core parameters of each asphalt sample and the corresponding standard core parameters at the same test temperature, the parameter change rates of the core parameters of each asphalt sample before and after aging at different test temperatures were obtained. The calculation formula is as follows:

[0075]

[0076] Among them, Q l,i,t It represents the parameter change rate of the i-th core parameter of the l-th asphalt sample at the t-th test temperature before and after aging. norm represents the normalization function. The normalization method here can be: obtain the maximum and minimum values ​​of all the parameter change rates before and after aging corresponding to the l-th asphalt sample, and then use the maximum and minimum value normalization method to normalize the value of the i-th core parameter before and after aging. Normalize it and put it into the numerical range of 0-1 to eliminate the dimension and facilitate subsequent calculations.

[0077] Using this method, we can determine the rate of change of each core parameter of each asphalt sample before and after aging at different test temperatures. By comparing the changes in core parameter data before and after aging, we can reflect the physical aging of the asphalt.

[0078] Step 2-1-3: Using the effect of each test temperature on aging as a weight, integrate the parameter change rates of each core parameter of the asphalt sample before and after aging at different test temperatures to obtain the initial aging performance of the asphalt sample.

[0079] After asphalt has been exposed to sunlight for a long time, oxidized and other factors, its composition and structure will change, resulting in an increase in viscosity and a decrease in elasticity and fluidity. Therefore, during the aging process of asphalt, especially under the accelerated conditions of high temperature, the physical and chemical changes caused by aging will become more obvious. Therefore, the core parameters of higher test temperatures can better reflect the aging performance of asphalt than the core parameters of lower test temperatures. The higher the test temperature, the more it can reflect the aging performance of asphalt. Then, the higher the test temperature, the more emphasis is placed on its corresponding core parameters. Therefore, the impact of each test temperature on aging is used as a weight, and the initial aging performance is defined based on the performance of asphalt samples at different test temperatures.

[0080] In one exemplary embodiment, the specific implementation method of using the impact of each test temperature on aging as a weight includes calculating the sum of all test temperatures and using the ratio of each test temperature to the sum as the weight of each test temperature. For example, if the test temperatures are 68°C and 24°C, the weight of the test temperature of 68°C is 68 / (68+24), and the weight of the test temperature of 24°C is 24 / (68+24). Therefore, the sum of the weights of all test temperatures is 1.

[0081] Based on the obtained weights of each test temperature, combined with the parameter change rates of each core parameter of the asphalt sample before and after aging at different test temperatures, the initial aging performance of the asphalt sample is obtained. In an exemplary embodiment, Figure 4 As shown, a specific calculation process of the initial aging performance is given as follows:

[0082] Step 2-1-3-1: Calculate the average value of the parameter change rate of each core parameter of the asphalt sample before and after aging at each test temperature to obtain the average parameter change rate of the asphalt sample before and after aging at the test temperature.

[0083] Step 2-1-3-2: Using the effect of each test temperature on aging as the weight, perform weighted summation on the average rate of change of parameters of the asphalt sample before and after aging at each test temperature to obtain the initial aging performance of the asphalt sample.

[0084] Based on the above steps, the calculation formula for the initial aging performance is as follows:

[0085]

[0086] Among them, W l represents the initial aging performance of the lth asphalt sample, T represents the number of test temperatures, I represents the number of types of core parameters, and s t Represents the weight of the tth test temperature.

[0087] Through the above method, the initial aging performance of each asphalt sample was obtained.

[0088] Step 2-2: Based on the fluctuations in the initial aging performance of the asphalt samples in the same batch, the degree of uneven and complex aging trend of the same batch is obtained.

[0089] Even though asphalt samples from the same batch originate from the same region, different samples may have been affected by different environmental factors during their use, such as temperature, humidity, and traffic load. Traffic load, in particular, affects asphalt aging at different rates due to the varying loads it experiences when used in locations with significantly different traffic volumes. Based on this, the degree of uneven and complex aging trends for the batch is determined based on the fluctuations in the initial aging performance of asphalt samples within the same batch.

[0090] In an exemplary embodiment, the standard deviation is used to represent the fluctuation. Then, the standard deviation of the initial aging performance of asphalt samples in the same batch is calculated, and the uneven and complex aging trend of the batch is obtained based on the obtained standard deviation. The calculation formula is as follows:

[0091]

[0092] Here, E represents the degree of uneven and complex aging trends of the asphalt samples in the batch, σ represents the calculated standard deviation, and L represents the number of asphalt samples in the batch. Since the standard deviation ranges from zero to zero, normalization can be performed using the following formula: 1-exp(-z), where z represents the normalization target (i.e., the standard deviation in this embodiment), and exp represents an exponential function with the natural constant e as its base.

[0093] Step 3: Obtain the first functional group and the second functional group of each asphalt sample, where the first functional group is the functional group with increased absorption peak intensity, and the second functional group is the functional group with decreased absorption peak intensity.

[0094] Step 2, using dynamic shear rheometer, reveals the uneven and complex aging trends of asphalt samples from the same batch. This analysis is based on the asphalt's macroscopic physical properties (inferring asphalt aging by measuring rheological properties). However, asphalt also undergoes chemical degradation during aging, particularly oxidation reactions. Therefore, this step reveals the chemical changes that cause aging, ultimately providing an accurate and comprehensive assessment of asphalt aging behavior.

[0095] Taking the first asphalt sample as an example, Fourier transform infrared spectroscopy (FTIR) is used to obtain the first functional group and the second functional group of the first asphalt sample. The first functional group is the functional group with increased absorption peak intensity, and the second functional group is the functional group with decreased absorption peak intensity.

[0096] The reason why functional groups with increased absorption peak intensity and functional groups with decreased absorption peak intensity are obtained is that during the aging process of asphalt, the generation of certain organic functional groups (such as esters, aldehydes, carboxylic acids, etc.) will cause the absorption peak intensity related to these functional groups to increase, while the absorption peak intensity of the original functional groups (such as CH stretching vibration and aromatic compound peaks) will decrease.

[0097] After obtaining the first functional group and the second functional group of the first asphalt sample, the number of functional groups contained in the first functional group and the number of functional groups contained in the second functional group are obtained, and the absorption peak intensity of each functional group contained in the first functional group and the absorption peak intensity of each functional group contained in the second functional group are also obtained.

[0098] Step 4: The internal chemical aging performance of the same batch of asphalt is obtained based on the difference between the absorption peak intensity of each functional group in the first functional group and the second functional group and the corresponding standard absorption peak intensity.

[0099] Obtain the standard absorption peak intensity. Similar to the process for obtaining the standard core parameters described above, Fourier transform infrared spectroscopy is used to obtain the absorption peak intensities of each functional group of the unaged asphalt sample, thereby obtaining the absorption peak intensities of each functional group of the unaged asphalt sample, which are defined as the standard absorption peak intensities.

[0100] The internal chemical aging performance of the same batch of asphalt is obtained by the difference between the absorption peak intensity of each functional group in the first functional group and the second functional group and the corresponding standard absorption peak intensity. The greater the difference, the stronger the internal chemical aging performance of the asphalt, that is, the more serious the internal chemical aging of the asphalt.

[0101] In an exemplary embodiment, Figure 5 As shown, a specific process for obtaining the internal chemical aging performance of asphalt is given as follows:

[0102] Step 4-1: Obtain the absorption peak intensity difference between the absorption peak intensity of each functional group in the first functional group and the second functional group and the standard absorption peak intensity of the corresponding functional group.

[0103] For the first asphalt sample, the absorption peak intensity difference between the absorption peak intensity of each functional group in the first functional group of the first asphalt sample and the standard absorption peak intensity of each corresponding functional group is obtained. In this embodiment, the absorption peak intensity difference is the absolute value of the difference in the absorption peak intensity. For example, the absolute value of the absorption peak intensity difference between the absorption peak intensity of functional group x in the first functional group of the first asphalt sample and the standard absorption peak intensity of functional group x is obtained. The first difference is set as the absorption peak intensity difference between the absorption peak intensity of each functional group in the first functional group of the first asphalt sample and the standard absorption peak intensity of the corresponding functional group.

[0104] Similarly, the absorption peak intensity difference between the absorption peak intensity of each functional group in the second functional group of the first asphalt sample and the standard absorption peak intensity of each corresponding functional group is obtained. In this embodiment, the absorption peak intensity difference is the absolute value of the difference in the absorption peak intensity. For example, the absolute value of the absorption peak intensity difference between the absorption peak intensity of functional group y in the second functional group of the first asphalt sample and the standard absorption peak intensity of functional group y is obtained. The second difference is set as the absorption peak intensity difference between the absorption peak intensity of each functional group in the second functional group of the first asphalt sample and the standard absorption peak intensity of the corresponding functional group.

[0105] Step 4-2: Integrate the absorption peak intensity differences in the asphalt sample to obtain the internal chemical aging performance of the asphalt sample.

[0106] All absorption peak intensity differences involved in the first asphalt sample are merged to obtain the internal chemical aging performance index of the first asphalt sample. In an exemplary embodiment, the internal chemical aging performance index of the first asphalt sample is obtained by calculating the sum of the first difference and the second difference in the first asphalt sample.

[0107] In an exemplary embodiment, the calculation formula for the internal chemical aging performance of an asphalt sample is given as follows:

[0108]

[0109] Among them, R l represents the internal chemical aging performance of the first asphalt sample, |Δr l,g | represents the absolute value of the difference between the absorption peak intensity of the gth functional group in the first functional group of the lth asphalt sample and the standard absorption peak intensity of the same functional group, |Δr l,g′ | represents the absolute value of the difference between the absorption peak intensity of the g′th functional group in the second functional group of the lth asphalt sample and the standard absorption peak intensity of the same functional group, G represents the number of functional groups contained in the first functional group of the lth asphalt sample, and G′ represents the number of functional groups contained in the second functional group of the lth asphalt sample.

[0110] Step 4-3: Obtain the internal chemical aging performance of the asphalt of the same batch based on the internal chemical aging performance of all asphalt samples in the same batch.

[0111] Step 4-2 obtains the internal chemical aging performance of each asphalt sample. Based on the internal chemical aging performance of all asphalt samples in the same batch, the internal chemical aging performance of the asphalt batch is obtained. In an exemplary embodiment, the internal chemical aging performance of each asphalt sample in the batch is averaged and then normalized to obtain the internal chemical aging performance of the asphalt batch. The calculation formula is as follows:

[0112]

[0113] Here, R represents the internal chemical aging performance of the asphalt batch. Normalization here can be performed as follows: 1-exp(-z), where z represents the treatment object and exp represents an exponential function with the natural constant e as the base.

[0114] Step 5: Combine the physical aging performance of asphalt and the internal chemical aging performance of asphalt to obtain the comprehensive aging performance of the same batch of asphalt.

[0115] Asphalt aging testing is typically performed using a single method, lacking a comprehensive approach. Dynamic shear rheometers analyze the physical properties, while Fourier transform infrared spectroscopy provides a chemical analysis. This integration of the physical and internal chemical aging characteristics of asphalt yields a comprehensive aging profile for the batch, enabling a more comprehensive and accurate analysis, facilitating subsequent thermal recycling of asphalt mixtures.

[0116] In an exemplary embodiment, Figure 6 As shown, a specific process for obtaining the comprehensive aging performance of asphalt is given as follows:

[0117] Step 5-1: Based on the initial aging performance of each asphalt sample, obtain the average initial aging performance of the same batch.

[0118] In step 2-1, the initial aging performance of each asphalt sample is obtained, and the average value of the initial aging performance of each asphalt sample in the same batch is calculated to obtain the average initial aging performance of the batch.

[0119] Step 5-2: Obtain the impact weight based on the unevenness and complex aging trend of the same batch.

[0120] In this embodiment, the uneven and complex aging trend degree E of the batch is used as the influence weight.

[0121] Step 5-3: Based on the impact weights, perform weighted summation of the average initial aging performance and internal chemical aging performance of asphalt of the same batch to obtain the comprehensive aging performance of asphalt of the same batch.

[0122] The uneven and complex aging trend of a batch of asphalt is assessed by the rheological properties of the asphalt samples within the batch, which indicates the consistency and aging differences of the batch. This reflects the complexity of the environmental impacts to which the batch of asphalt is subjected during actual use. The greater the impact of actual environmental factors, the more attention should be paid to its internal chemical aging performance. When the impact of environmental factors is smaller (the aging differences of the asphalt samples are small, the relevant properties of the material do not change much during use, and the asphalt is more stable), more attention should be paid to the initial aging performance of the asphalt samples.

[0123] Therefore, in one exemplary embodiment, Figure 7 As shown, a specific calculation process for the comprehensive aging performance of this batch of asphalt is given as follows:

[0124] Step 5-3-1: Calculate the product of the internal chemical aging performance of asphalt and the impact weight to obtain the first product.

[0125] Step 5-3-2: Calculate the product of the average initial aging performance and the negative correlation weight to obtain a second product.

[0126] Step 5-3-3: Calculate the sum of the first product and the second product as the comprehensive aging performance of the same batch of asphalt.

[0127] Among them, the sum of the negative correlation weight and the influence weight is 1, and the negative correlation weight is obtained by the influence weight.

[0128] In an exemplary embodiment, the calculation formula for the comprehensive aging performance of asphalt is given as follows:

[0129]

[0130] Among them, Y represents the comprehensive aging performance of the asphalt of this batch, represents the average initial aging performance of the batch, and (1-E) represents the negative correlation weight. By taking a weighted sum of the physical and chemical aging characteristics of each asphalt sample within the same batch, we can more accurately assess the aging trend of the asphalt samples within that batch.

[0131] Thus, the asphalt samples of the same batch are analyzed to obtain the comprehensive aging performance of the asphalt of the batch. If multiple batches of asphalt are initially obtained in this embodiment, the above process is followed for each other batch of asphalt to obtain the comprehensive aging performance of each batch of asphalt.

[0132] A higher value for the asphalt's comprehensive aging performance (Y) indicates a higher degree of aging for that batch of asphalt. Subsequently, a threshold for asphalt aging can be set, with batches of asphalt corresponding to a comprehensive aging performance greater than or equal to the threshold being designated as highly aged, and batches of asphalt corresponding to a comprehensive aging performance less than the threshold being designated as less aged. Furthermore, in subsequent applications, the higher the asphalt's aging, the more additives will be required to meet subsequent recycling requirements. Therefore, when completing asphalt aging testing in subsequent applications, relevant test data can be included to facilitate subsequent additive replenishment by professionals. This will not be discussed further.

[0133] It should be noted that the order in which the embodiments of the present invention are described above is for illustrative purposes only and does not necessarily represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or sequential order shown to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0134] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

Claims

1. A method for detecting the degree of asphalt aging for thermal recycling of asphalt mixture, characterized in that: include: Obtain samples of various asphalts from the same batch; At different test temperatures, each asphalt sample is tested using a dynamic shear rheometer to obtain the physical aging performance of the asphalt of the same batch; Obtaining a first functional group and a second functional group of each asphalt sample, wherein the first functional group is a functional group with an increased absorption peak intensity, and the second functional group is a functional group with a decreased absorption peak intensity; Obtaining the internal chemical aging performance of the same batch of asphalt according to the difference between the absorption peak intensity of each functional group in the first functional group and the second functional group and the corresponding standard absorption peak intensity; The physical aging performance of the asphalt and the internal chemical aging performance of the asphalt are integrated to obtain the comprehensive aging performance of the asphalt of the same batch.

2. The asphalt aging degree detection method for asphalt mixture thermal recycling according to claim 1 is characterized in that: The asphalt samples were tested using a dynamic shear rheometer at different test temperatures to obtain the physical aging performance of the asphalt of the same batch, including: At different test temperatures, each asphalt sample was tested using a dynamic shear rheometer to obtain the initial aging performance of each asphalt sample; According to the fluctuation of the initial aging performance of each asphalt sample in the same batch, the uneven and complex aging trend degree of the same batch is obtained.

3. The asphalt aging degree detection method for asphalt mixture thermal recycling as claimed in claim 2, characterized in that: At different test temperatures, each asphalt sample was tested using a dynamic shear rheometer to obtain the initial aging performance of each asphalt sample, including: At different test temperatures, each asphalt sample was tested using a dynamic shear rheometer to obtain the core parameters of each asphalt sample; Based on the differences between the core parameters of each asphalt sample and the corresponding standard core parameters at the same test temperature, the parameter change rates of the core parameters of each asphalt sample before and after aging at different test temperatures were obtained; The effect of each test temperature on aging is used as a weight, and the parameter change rates of each core parameter of each asphalt sample before and after aging at different test temperatures are integrated to obtain the initial aging performance of each asphalt sample.

4. The asphalt aging degree detection method for hot recycling of asphalt mixture according to claim 3 is characterized in that: The weights of the effects of various test temperatures on aging include: The sum of the temperatures of all the test temperatures is calculated, and the ratio of each test temperature to the sum of the temperatures is used as the weight of each test temperature.

5. The asphalt aging degree detection method for asphalt mixture thermal recycling as claimed in claim 3, characterized in that: The effects of various test temperatures on aging are weighted, and the parameter change rates of various core parameters of each asphalt sample before and after aging at different test temperatures are integrated to obtain the initial aging performance of each asphalt sample, including: For any asphalt sample from the same batch, calculate the average value of the parameter change rate of each core parameter of the asphalt sample before and after aging at each test temperature, and obtain the average parameter change rate of the asphalt sample before and after aging at the test temperature; Taking the effect of each test temperature on aging as the weight, the average change rate of the parameters of the asphalt samples before and after aging at each test temperature was weighted and summed to obtain the initial aging performance of the asphalt samples.

6. A method for detecting the degree of asphalt aging for thermal recycling of asphalt mixture according to any one of claims 1 to 5, characterized in that: The internal chemical aging performance of the same batch of asphalt is obtained based on the difference between the absorption peak intensity of each functional group in the first functional group and the second functional group and the corresponding standard absorption peak intensity, including: Obtaining an absorption peak intensity difference between the absorption peak intensity of each functional group in the first functional group and the second functional group and the standard absorption peak intensity of the corresponding functional group; Combining the absorption peak intensity differences in each asphalt sample to obtain the internal chemical aging performance of each asphalt sample; According to the internal chemical aging performance of all asphalt samples in the same batch, the internal chemical aging performance of the asphalt in the same batch is obtained.

7. The asphalt aging degree detection method for asphalt mixture thermal recycling according to claim 6, characterized in that: The internal chemical aging performance of each asphalt sample is obtained by integrating the absorption peak intensity differences in each asphalt sample, including: Calculate the sum of the first difference and the second difference in the first asphalt sample to obtain the internal chemical aging performance of the first asphalt sample; the first asphalt sample is any asphalt sample, and the first difference is the difference in absorption peak intensity between the absorption peak intensity of each functional group in the first functional group of the first asphalt sample and the standard absorption peak intensity of the corresponding functional group; the second difference is the difference in absorption peak intensity between the absorption peak intensity of each functional group in the second functional group of the first asphalt sample and the standard absorption peak intensity of the corresponding functional group.

8. The asphalt aging degree detection method for asphalt mixture thermal recycling according to claim 6, characterized in that: The internal chemical aging performance of the asphalt of the same batch is obtained based on the internal chemical aging performance of all asphalt samples in the same batch, including: The average value of the internal chemical aging performance of each asphalt sample in the same batch is calculated as the internal chemical aging performance of the asphalt in the same batch.

9. The asphalt aging degree detection method for asphalt mixture thermal recycling as claimed in claim 2, characterized in that: The integration of the physical aging performance of asphalt and the internal chemical aging performance of asphalt to obtain the comprehensive aging performance of the same batch of asphalt includes: According to the initial aging performance of each asphalt sample, the average initial aging performance of the same batch is obtained; Obtaining an impact weight based on the uneven and complex aging trend of the same batch; According to the influence weights, the average initial aging performance and the internal chemical aging performance of the asphalt of the same batch are weightedly summed to obtain the comprehensive aging performance of the asphalt of the same batch.

10. The asphalt aging degree detection method for asphalt mixture thermal recycling according to claim 9, characterized in that: The weighted sum of the average initial aging performance and the internal chemical aging performance of the asphalt of the same batch is performed according to the influence weight to obtain the comprehensive aging performance of the asphalt of the same batch, including: Calculating the product of the internal chemical aging performance of the asphalt and the impact weight to obtain a first product; Calculating the product of the average initial aging performance and the negative correlation weight to obtain a second product; the sum of the negative correlation weight and the impact weight is 1; The sum of the first product and the second product is calculated as the comprehensive aging performance of the asphalt of the same batch.

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