Method for evaluating compatibility of waste plastic modified asphalt based on infrared spectrum technology

Abstract

The invention relates to the technical field of road engineering, in particular to a waste plastic modified asphalt compatibility evaluation method based on an infrared spectrum technology, which comprises the following steps: preparing a to-be-tested plastic sheet, and carrying out infrared spectrum analysis on the to-be-tested plastic sheet; calculating the corresponding characteristic peak area of the to-be-tested plastic sheet according to the obtained infrared spectrum data; taking each characteristic peak area of the to-be-tested plastic sheet as an input variable, taking known plastic and asphalt compatibility data as an output variable, and establishing a standard mathematical relationship model; and substituting the infrared spectrum data of the plastic sheet sample into the standard mathematical relationship model, and calculating an output compatibility index, namely the softening point difference. According to the method, the sample preparation process is simplified, and the compatibility of the plastic and the asphalt is predicted by utilizing the infrared spectrum test and the standard mathematical relationship model, so that tedious operation steps in a traditional test method are avoided, and the method has the characteristics of short time consumption, high accuracy, wide adaptability and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of road engineering, and specifically provides a method for evaluating the compatibility of waste plastic modified asphalt based on infrared spectroscopy technology. Background Art

[0002] As an important pavement raw material, the performance of asphalt directly affects the service life, driving safety, and maintenance cost of high-grade asphalt pavements. Traditional asphalt materials are prone to diseases such as fatigue, cracks, and ruts during long-term use, resulting in the gradual degradation of pavement functions.

[0003] As a new type of additive in modified asphalt, waste plastics can effectively improve the rutting resistance, fatigue resistance, low-temperature crack resistance, etc. of asphalt, thereby enhancing the service life and driving safety of roads. Although waste plastic modified asphalt has significant advantages in performance, the compatibility problem between plastics and asphalt remains the core difficulty restricting its wide application. The physical and chemical properties of plastics and asphalt are quite different, often resulting in uneven dispersion during the mixing process, which in turn affects the long-term stability and use effect of their composite materials. Therefore, how to accurately quantify the compatibility between plastics and asphalt and propose reasonable and effective measures to improve this compatibility has become an important topic in the research of waste plastic modified asphalt.

[0004] Existing compatibility testing methods are mostly physical or chemical tests, such as solubility parameter method, thermodynamic model method, microscope observation method, etc. Although these methods can reveal the compatibility between plastics and asphalt to a certain extent, they often have disadvantages such as complex operation, long time consumption, low efficiency, and poor result accuracy. Especially in actual production and engineering applications, it is crucial to quickly and accurately evaluate the compatibility. Therefore, there is an urgent need for a simple, efficient, and more accurate compatibility prediction method to provide strong support in asphalt mixture design and the selection of plastic modifiers. Summary of the Invention

[0005] Aiming at the deficiencies of the existing technology, the present invention provides a method for evaluating the compatibility of waste plastic modified asphalt based on infrared spectroscopy technology. By simplifying the sample preparation process and using infrared spectroscopy testing and standard mathematical relationship models to predict the compatibility of plastics and asphalt, the cumbersome operation steps in traditional testing methods are avoided, and it has the characteristics of short time consumption, high accuracy, and wide adaptability.

[0006] To achieve the above object, the present invention provides the following technical solution: A method for evaluating the compatibility of waste plastic modified asphalt based on infrared spectroscopy technology, comprising the following steps,

[0007] (1) Prepare multiple groups of plastic sheets to be tested and perform infrared spectroscopy analysis on them;

[0008] (2) According to the acquired infrared spectrum data, analyze the absorption peaks of the plastic sheets to be tested in each group within a specific wavelength range, and calculate the corresponding characteristic peak areas of the plastic sheets to be tested in each group based on the peak positions and peak heights of the absorption peaks of each characteristic functional group.

[0009] (3) Take the characteristic peak areas of the plastic sheets to be tested in each group as input variables, and use the known data on the compatibility of plastics and asphalt as output variables to establish a standard mathematical relationship model.

[0010] (4) Substitute the characteristic peak areas of the plastic sheet samples prepared according to the method in step (1) into the above standard mathematical relationship model, and calculate the compatibility index output by the standard mathematical relationship model, which is the softening point difference and represents the degree of compatibility between the plastic sheet samples and asphalt.

[0011] Preferably, in step (1), the plastic sheets to be tested are selected from the plastic sheets to be tested of polyethylene, the plastic sheets to be tested of polyethylene terephthalate, the plastic sheets to be tested of polypropylene, and the plastic sheets to be tested of polyvinyl chloride.

[0012] Preferably, in step (1), the preparation method of the plastic sheets to be tested is as follows: Grind the waste plastics into fine powders, ensuring that the particle size of the fine powders is below 50 μm; uniformly mix the fine powders with dry potassium bromide powder in a mass ratio of 1:100; press the obtained mixture into transparent sample sheets, and thus obtain the plastic sheets to be tested.

[0013] Preferably, during the infrared spectrum analysis, the wavelength range is selected as 4000 - 400 cm -1 ; set the resolution to 4 cm -1 ; set the number of scans to 32 times; set the scanning speed to 1 cm / s.

[0014] Preferably, in step (2), the specific wavelength range is selected as 2500 - 700 cm -1 .

[0015] Preferably, in step (2), the calculation formula for the characteristic peak area is as follows:

[0016]

[0017] Where: A is the characteristic peak area; y(x) is the absorption intensity or transmittance value in the infrared spectrum; x 1 and x 2 are the starting and ending wave numbers of the peak.

[0018] Preferably, in step (3), the known plastic-asphalt compatibility data includes the softening point difference between polyethylene plastic and asphalt, the softening point difference between polyethylene terephthalate plastic and asphalt, the softening point difference between polypropylene plastic and asphalt, and the softening point difference between polyvinyl chloride plastic and asphalt.

[0019] Preferably, in step (3), a non-linear polynomial regression model is used to fit the relationship between the characteristic peak area and the plastic-asphalt compatibility. The established mathematical relationship model is as follows:

[0020] Y = f(X, β) + ε

[0021]

[0022] In the formula: Y is the index of plastic-asphalt compatibility, that is, the softening point difference; f(X, β) is a non-linear fitting function, which depends on the characteristic variable X, that is, the relationship coefficient γ between each characteristic peak area, regression coefficient β and spectral characteristics ij ; β 0 represents the relationship between the plastic sample and compatibility; represents the relationship between a single characteristic peak of the plastic sample and compatibility; represents the relationship between the interaction between the characteristic peaks of the plastic sample and compatibility; ε is the error term.

[0023] Preferably, to prevent the influence of the numerical range on the fitting result, the characteristic variable X and the response variable Y need to be standardized. The established standard mathematical relationship model is as follows:

[0024]

[0025] In the formula: μ i 、σ i are the mean and standard deviation of the i-th characteristic variable; μ Y 、σ Y are the mean and standard deviation of the compatibility index; β 0 ' represents the relationship between the whole plastic sample and compatibility after standardization; represents the relationship between a single characteristic peak of the plastic sample and compatibility after standardization; represents the relationship between the interaction between the characteristic peaks of the plastic sample and compatibility after standardization; ε′ is the relationship after standardization of the error term.

[0026] The present invention provides a method for evaluating the compatibility of waste plastic modified asphalt based on infrared spectroscopy technology, which has the following beneficial effects compared with the prior art:

[0027] The present invention simplifies the sample preparation process and uses infrared spectroscopy testing and a standard mathematical relationship model to predict the compatibility of plastics and asphalt, avoiding the cumbersome operation steps in traditional testing methods, and having the characteristics of short time consumption, high accuracy, and wide adaptability. Among them, through the precise analysis of the characteristic peak area and the establishment of a compatibility prediction model, it can provide an accurate prediction of the compatibility of waste plastic modified asphalt, providing an important reference for material selection and optimization. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings described herein are used to provide a further understanding of the present application, form a part of the present application, and the illustrative embodiments and descriptions thereof are used to explain the present application and do not constitute an improper limitation to the present application. In the drawings:

[0029] Figure 1 is the infrared spectrogram of different plastics of the present invention;

[0030] Figure 2 is a schematic diagram for calculating the characteristic peak area of the infrared spectrum of the present invention;

[0031] Figure 3 is a schematic diagram of the infrared spectrum equipment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The following embodiments are used to illustrate the implementation manners of the present application in detail, so as to fully understand how the present application uses technical means to solve technical problems and achieve the implementation process of technical effects and implement accordingly.

[0033] Example 1

[0034] Establishing a standard mathematical model, including:

[0035] (1) Grind the waste plastic into fine powder to ensure that the particle size of the fine powder is below 50 μm; uniformly mix the fine powder with dry potassium bromide powder at a mass ratio of 1:100; press the obtained mixture into a transparent sample tablet to obtain the plastic tablet to be tested.

[0036] The plastic tablets to be tested prepared here include polyethylene plastic tablets to be tested, polyethylene terephthalate plastic tablets to be tested, polypropylene plastic tablets to be tested, and polyvinyl chloride plastic tablets to be tested.

[0037] (2) Perform infrared spectrum analysis on the plastic tablets to be tested in each group, and select the wavelength range of 4000 - 400 cm -1 ; set the resolution to 4 cm -1 ; set the number of scans to 32 times; set the scan speed to 1 cm / s.

[0038] (3) According to the acquired infrared spectrum data, analyze the absorption peaks of the test plastic sheets in each group within a specific wavelength range (select 2500 - 700 cm -1 ). Based on the peak positions and peak heights of the absorption peaks of each characteristic functional group, calculate the corresponding characteristic peak areas of the test plastic sheets in each group;

[0039] The calculation formula for the characteristic peak area is as follows:

[0040]

[0041] In the formula: A is the characteristic peak area; y(x) is the absorption intensity or transmittance value in the infrared spectrum; x 1 and x 2 are the starting and ending wavenumbers of the peak.

[0042] (4) Take the characteristic peak areas of the test plastic sheets in each group (including the characteristic peak areas of the test polyethylene plastic sheets, the characteristic peak areas of the test polyethylene terephthalate plastic sheets, the characteristic peak areas of the test polypropylene plastic sheets, and the characteristic peak areas of the test polyvinyl chloride plastic sheets) as input variables, and use the known plastic and asphalt compatibility data (the softening point difference between polyethylene plastic and asphalt, 2.5 °C, the softening point difference between polyethylene terephthalate plastic and asphalt, 5.4 °C, the softening point difference between polypropylene plastic and asphalt, 3.7 °C, the softening point difference between polyvinyl chloride plastic and asphalt, 5.2 °C) as output variables to establish a standard mathematical relationship model;

[0043] Adopt a non - linear polynomial regression model to fit the relationship between the characteristic peak area and the plastic - asphalt compatibility. The established mathematical relationship model is as follows:

[0044] Y = f(X, β)+ε

[0045]

[0046] In the formula: Y is the index of plastic - asphalt compatibility, that is, the softening point difference; f(X, β) is a non - linear fitting function, which depends on the characteristic variable X, that is, the relationship between each characteristic peak area, the regression coefficient β, and the correlation coefficient γ of the spectral characteristics ij ; β 0 represents the relationship between the plastic sample and compatibility; represents the relationship between a single characteristic peak of the plastic sample and compatibility; represents the relationship between the interaction between the characteristic peaks of the plastic sample and compatibility; ε is the error term.

[0047] To prevent the influence of the numerical range on the fitting result, the characteristic variable X and the response variable Y need to be standardized;

[0048]

[0049] The established standard mathematical relationship model is as follows:

[0050]

[0051] In the formula: μ i , σ i are the mean and standard deviation of the i-th characteristic variable; μ Y , σ Y are the mean and standard deviation of the compatibility index; β 0 ' represents the relationship between the whole plastic sample and the standardized compatibility; represents the relationship between a single characteristic peak of the plastic sample and the standardized compatibility; represents the relationship between the interaction between the characteristic peaks of the plastic sample and the standardized compatibility; ε' is the relationship after standardizing the error term.

[0052] (5) Substitute the infrared spectrum data (the area of each characteristic peak) of the plastic sheet sample prepared according to the method in step (1) into the above standard mathematical relationship model, and calculate the compatibility index output by the standard mathematical relationship model, which is the softening point difference, and it represents the compatibility degree between the plastic sheet sample and the asphalt.

[0053] The softening point difference is one of the important indexes for evaluating the compatibility between asphalt and modifier. It reflects the interaction strength between asphalt and modifier, and is usually used to judge the dispersion state and compatibility of the modifier in asphalt. Small softening point difference (≤2.5 °C): good compatibility and excellent performance. Medium softening point difference (2.5 °C - 5 °C): medium compatibility and limited performance improvement. Large softening point difference (>5 °C): poor compatibility and deteriorated performance.

[0054] Example 2

[0055] A method for evaluating the compatibility of waste plastic modified asphalt based on infrared spectrum technology, including:

[0056] (1) Select waste plastic of polyethylene (PE) as the sample and grind it into fine powder, ensuring that the particle size of the fine powder is below 50 μm; uniformly mix the fine powder with dry potassium bromide powder at a mass ratio of 1:100; press the obtained mixture into a transparent sample sheet, ensuring that the thickness of the sample sheet is uniform and convenient for infrared light to pass through.

[0057] (2) Place the sample sheet on the sample holder of the infrared spectrometer, ensure good contact between the sample sheet and the optical system, and perform infrared spectrum analysis on it; select the wavelength range of 4000 - 400 cm -1 ; set the resolution to 4 cm -1 ; set the number of scans to 32 times; set the scanning speed to 1 cm / s.

[0058] (3) Based on the obtained infrared spectrum data, analyze the absorption peaks of the sample wafer to be tested in a specific wavelength range (select 2500 - 700 cm -1 ), and calculate the corresponding characteristic peak areas of the sample wafer according to the peak positions and peak heights of the absorption peaks of each characteristic functional group.

[0059] (4) Substitute the characteristic peak areas into the standard mathematical relationship model in Example 1 to calculate the compatibility index output by the model, and this index is the softening point difference.

[0060] The waste polyethylene plastic selected in this example is not from the same batch as that in Example 1.

[0061] The infrared spectrum analysis and calculation results of the waste PE plastic sample wafer are shown in Table 1.

[0062] Table 1 Waste PE plastic sample wafer

[0063]

[0064]

[0065] Example 3

[0066] A method for evaluating the compatibility of waste plastic modified asphalt based on infrared spectrum technology is basically the same as that in Example 2, except that: the waste PE plastic is replaced by waste polyethylene terephthalate (PET) plastic.

[0067] The waste polyethylene terephthalate plastic selected in this example is not from the same batch as that in Example 1.

[0068] The infrared spectrum analysis and calculation results of the waste PET plastic sample wafer are shown in Table 2.

[0069] Table 2 Waste PET plastic sample wafer

[0070]

[0071]

[0072] Example 4

[0073] A method for evaluating the compatibility of waste plastic modified asphalt based on infrared spectrum technology is basically the same as that in Example 2, except that: the waste PE plastic is replaced by waste polyvinyl chloride (PVC) plastic.

[0074] The waste polyvinyl chloride plastic selected in this example is not from the same batch as that in Example 1.

[0075] The infrared spectrum analysis and calculation results of the waste PVC plastic sample wafer are shown in Table 3.

[0076] Table 3 PVC waste plastic sample pieces

[0077]

[0078] Example 5

[0079] A method for evaluating the compatibility of waste plastic modified asphalt based on infrared spectroscopy is basically the same as that in Example 2, except that: the PE waste plastic is replaced with polypropylene (PP) waste plastic.

[0080] The polypropylene waste plastic selected in this example is not from the same batch as that in Example 1.

[0081] The calculation results of infrared spectrum analysis of PP waste plastic sample pieces are shown in Table 4.

[0082] Table 4 PP waste plastic sample pieces

[0083]

[0084] Example 6

[0085] A method for evaluating the compatibility of waste plastic modified asphalt based on infrared spectroscopy is basically the same as that in Example 2, except that: the PE waste plastic is replaced with low-density polyethylene (LDPE) waste plastic.

[0086] The calculation results of infrared spectrum analysis of LDPE waste plastic sample pieces are shown in Table 5.

[0087] Table 5 LDPE waste plastic sample pieces

[0088]

[0089]

[0090] Comparative Example 1

[0091] A method for testing the compatibility of waste plastic modified asphalt includes:

[0092] Conduct a 48-hour heat storage test of the 4.0% PE modified asphalt sample in a segregation tube (refer to T 0661-2011 in the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" JTG E20-2011). First, prepare the synthesized PE modified asphalt sample, with each sample weighing approximately 50 g, and place it vertically in a special aluminum test tube with a diameter of 25 mm and a length of 140 mm. Subsequently, place the test tube in a high-temperature oven at 163 °C. After heating the asphalt to a flowing state, quickly transfer the test tube to a refrigerator for at least 4 hours of freezing treatment to ensure that the asphalt sample is fully cooled and solidified. After the freezing is completed, evenly cut each asphalt sample into three sections along the length direction, and conduct softening point tests on the asphalt parts in the upper and lower sections of the test tube respectively. Each modified asphalt is tested twice. Calculate the difference between the softening points of the two parts. The magnitude of this difference directly reflects the tendency of component separation of the asphalt due to temperature fluctuations during storage, and is used to quantitatively evaluate the segregation degree of different waste plastic modified asphalt blends, that is, the compatibility of waste plastic modified asphalt.

[0093] The PE waste plastic used in this comparative example is from the same batch as that in Example 2.

[0094] Comparative Example 2

[0095] A method for testing the compatibility of waste plastic modified asphalt includes:

[0096] Conduct a 48-hour heat storage test of the 4.0% PET modified asphalt sample in a segregation tube (refer to T 0661-2011 in the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" JTG E20-2011). First, prepare the synthesized PET modified asphalt sample, with each sample weighing approximately 50 g, and place it vertically in a special aluminum test tube with a diameter of 25 mm and a length of 140 mm. Subsequently, place the test tube in a high-temperature oven at 163 °C. After heating the asphalt to a flowing state, quickly transfer the test tube to a refrigerator for at least 4 hours of freezing treatment to ensure that the asphalt sample is fully cooled and solidified. After the freezing is completed, evenly cut each asphalt sample into three sections along the length direction, and conduct softening point tests on the asphalt parts in the upper and lower sections of the test tube respectively. Each modified asphalt is tested twice. Calculate the difference between the softening points of the two parts. The magnitude of this difference directly reflects the tendency of component separation of the asphalt due to temperature fluctuations during storage, and is used to quantitatively evaluate the segregation degree of different waste plastic modified asphalt blends, that is, the compatibility of waste plastic modified asphalt.

[0097] The PET waste plastic used in this comparative example is from the same batch as that in Example 3.

[0098] Comparative Example 3

[0099] A method for testing the compatibility of waste plastic modified asphalt includes:

[0100] Conduct a 48-hour heat storage test of the 4.0% PVC modified asphalt sample in a segregation tube (refer to T 0661-2011 "Test Procedures for Bitumen and Bituminous Mixtures in Highway Engineering" in JTG E20-2011). First, prepare the synthesized PVC modified asphalt sample, with each sample weighing approximately 50 g. Vertically place it in a special aluminum test tube with a diameter of 25 mm and a length of 140 mm. Subsequently, place the test tube in a high-temperature oven at 163 °C. After heating the asphalt to a flowing state, quickly transfer the test tube to a refrigerator for at least 4 hours of freezing treatment to ensure that the asphalt sample is fully cooled and solidified. After the freezing is completed, evenly cut each asphalt sample into three segments along the length direction, and conduct softening point tests on the asphalt parts in the upper and lower segments of the test tube respectively. Each modified asphalt is tested twice. Calculate the difference between the softening points of the two parts. The magnitude of this difference directly reflects the tendency of component separation of the asphalt due to temperature fluctuations during storage, and is used to quantitatively evaluate the segregation degree of different waste plastic modified asphalt blends, that is, the compatibility of waste plastic modified asphalt.

[0101] The PVC waste plastic used in this comparative example is from the same batch as that in Example 4.

[0102] Comparative Example 4

[0103] A method for testing the compatibility of waste plastic modified asphalt, including:

[0104] Conduct a 48-hour heat storage test of the 4.0% PP modified asphalt sample in a segregation tube (refer to T 0661-2011 "Test Procedures for Bitumen and Bituminous Mixtures in Highway Engineering" in JTG E20-2011). First, prepare the synthesized PP modified asphalt sample, with each sample weighing approximately 50 g. Vertically place it in a special aluminum test tube with a diameter of 25 mm and a length of 140 mm. Subsequently, place the test tube in a high-temperature oven at 163 °C. After heating the asphalt to a flowing state, quickly transfer the test tube to a refrigerator for at least 4 hours of freezing treatment to ensure that the asphalt sample is fully cooled and solidified. After the freezing is completed, evenly cut each asphalt sample into three segments along the length direction, and conduct softening point tests on the asphalt parts in the upper and lower segments of the test tube respectively. Each modified asphalt is tested twice. Calculate the difference between the softening points of the two parts. The magnitude of this difference directly reflects the tendency of component separation of the asphalt due to temperature fluctuations during storage, and is used to quantitatively evaluate the segregation degree of different waste plastic modified asphalt blends, that is, the compatibility of waste plastic modified asphalt.

[0105] The PP waste plastic used in this comparative example is from the same batch as that in Example 5.

[0106] Comparative Example 5

[0107] A method for testing the compatibility of waste plastic modified asphalt, comprising:

[0108] Conduct a segregation tube heat storage test on a 4.0% LDPE modified asphalt sample for 48 hours (refer to JTG E20 - 2011 "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" T 0661 - 2011). First, prepare the synthesized LDPE modified asphalt sample, with each sample weighing about 50 g. Vertically place it in a special aluminum test tube with a diameter of 25 mm and a length of 140 mm. Subsequently, place the test tube in a high - temperature oven at 163 °C. After heating the asphalt to a flowing state, quickly transfer the test tube to a refrigerator for at least 4 hours of freezing treatment to ensure that the asphalt sample is fully cooled and solidified. After freezing, evenly cut each asphalt sample into three sections along the length direction, and conduct softening point tests on the asphalt parts in the upper and lower sections of the test tube respectively. Each modified asphalt is tested twice. Calculate the difference between the softening points of the two parts. The magnitude of this difference directly reflects the tendency of component separation of the asphalt due to temperature fluctuations during storage, and is used to quantitatively evaluate the segregation degree of different waste plastic modified asphalt blends, that is, the compatibility of waste plastic modified asphalt.

[0109] The LDPE waste plastic used in this comparative example is from the same batch as that in Example 6.

[0110] Prediction and verification of the compatibility between plastic and asphalt

[0111] Two groups of tests were conducted. Among them, the softening point difference calculated by the standard mathematical model in the example is denoted as the predicted value; the softening point difference obtained in the comparative example is denoted as the measured value. The test results are shown in Table 2.

[0112] Table 2 Compatibility

[0113]

[0114] As can be seen from the above table: the correlation degrees R of the two groups of samples of the measured value and the predicted value 2 Are 0.94 and 0.99 respectively, indicating that the method for evaluating the compatibility performance of waste plastic modified asphalt based on infrared spectroscopy technology proposed by the present invention has accurate prediction results.

[0115] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for evaluating the compatibility of waste plastic modified asphalt based on infrared spectroscopy technology, characterized in that: The following steps are involved: (1) preparing multiple groups of plastic sheets to be tested and performing infrared spectroscopy analysis on them; (2) Analyze the absorption peaks of each group of plastic sheets to be tested within a specific wavelength range based on the acquired infrared spectrum data, and calculate the corresponding characteristic peak areas of each group of plastic sheets to be tested based on the peak positions and peak heights of the absorption peaks of each characteristic functional group; (3) Using the characteristic peak areas of each group of tested plastic sheets as input variables and the known compatibility data of plastics and asphalt as output variables, a standard mathematical relationship model is established; (4) Substituting the characteristic peak areas of the plastic sheet sample prepared according to the method in step (1) into the above-mentioned standard mathematical relationship model, calculating the compatibility index output by the standard mathematical relationship model, namely the softening point difference, which represents the degree of compatibility between the plastic sheet sample and asphalt.

2. The method for evaluating the compatibility of waste plastic modified asphalt based on infrared spectroscopy technology according to claim 1 is characterized in that: In step (1), the plastic sheet to be tested is selected from a polyethylene plastic sheet to be tested, a polyethylene terephthalate plastic sheet to be tested, a polypropylene plastic sheet to be tested, and a polyvinyl chloride plastic sheet to be tested.

3. The method for evaluating the compatibility of waste plastic modified asphalt based on infrared spectroscopy technology according to claim 2 is characterized in that: The preparation method of the plastic sheet to be tested is as follows: grinding waste plastic into fine powder, ensuring that the particle size of the fine powder is below 50 μm; uniformly mixing the fine powder with dry potassium bromide powder at a mass ratio of 1:100; pressing the obtained mixture into a transparent sample sheet to obtain the plastic sheet to be tested.

4. The method for evaluating the compatibility of waste plastic modified asphalt based on infrared spectroscopy technology according to claim 2 is characterized in that: In the infrared spectrum analysis, the wavelength range is selected from 4000 to 400 cm -1 ; Set the resolution to 4cm -1 ; The number of scans was set to 32 times; The scanning speed was set to 1 cm / s.

5. The method for evaluating the compatibility of waste plastic modified asphalt based on infrared spectroscopy technology according to claim 1 is characterized in that: In step (2), the specific wavelength range is selected from 2500 to 700 cm -1 .

6. The method for evaluating the compatibility of waste plastic modified asphalt based on infrared spectroscopy technology according to claim 1, characterized in that: In step (2), the characteristic peak area calculation formula is as follows: Where: A is the characteristic peak area; y(x) is the absorption intensity or transmittance value in the infrared spectrum; x1 and x2 are the starting and ending wavenumbers of the peak.

7. The method for evaluating the compatibility of waste plastic modified asphalt based on infrared spectroscopy technology according to claim 2 is characterized in that: In step (3), the known plastic and asphalt compatibility data include the softening point difference between polyethylene plastic and asphalt, the softening point difference between polyethylene terephthalate plastic and asphalt, the softening point difference between polypropylene plastic and asphalt, and the softening point difference between polyvinyl chloride plastic and asphalt.

8. The method for evaluating the compatibility of waste plastic modified asphalt based on infrared spectroscopy technology according to claim 1 is characterized in that: In step (3), a nonlinear polynomial regression model is used to fit the relationship between the characteristic peak area and the compatibility of plastic and asphalt. The established mathematical relationship model is as follows: Y=f(X,β)+ε Where: Y is the index of compatibility between plastic and asphalt, i.e., softening point difference; f(X, β) is a nonlinear fitting function, which depends on the characteristic variable X, i.e., the relationship coefficient γ between each characteristic peak area, regression coefficient β and spectral characteristics ij ; β0 represents the relationship between plastic sample and compatibility; Represents the relationship between a single characteristic peak of a plastic sample and its compatibility; It represents the relationship between the interaction between the characteristic peaks of plastic samples and compatibility; ε is the error term.

9. The method for evaluating the compatibility of waste plastic modified asphalt based on infrared spectroscopy technology according to claim 8, characterized in that: In order to prevent the numerical range from affecting the fitting results, the characteristic variable X and the response variable Y need to be standardized. The established standard mathematical relationship model is as follows:

10. Where: μ i , σ i is the mean and standard deviation of the ith characteristic variable; μ Y , σ Y is the mean and standard deviation of the compatibility index; β0' represents the relationship between the overall plastic sample and the standardized compatibility; Represents the relationship between a single characteristic peak of a plastic sample and the normalized compatibility; It represents the relationship between the interaction between the characteristic peaks of plastic samples and the standardized compatibility; ε' is the relationship after the standardized error term.

Images