DSR-based method for rapidly predicting low-temperature performance of asphalt

Abstract

The invention relates to the technical field of road engineering, in particular to a DSR-based method for rapidly predicting low-temperature performance of asphalt, which comprises the following steps: preparing an asphalt cylinder sample; performing a strain amplitude scanning test to obtain a linear viscoelasticity interval; performing frequency scanning test to obtain asphalt dynamic modulus and phase angle data at different frequencies at low temperature; according to the prediction model, converting the dynamic modulus and the phase angle into a creep stiffness modulus and a creep stiffness modulus change rate; and finally, according to a low-temperature performance grade evaluation standard, obtaining the low-temperature grade of the asphalt sample. According to the method, the low-temperature performance of the asphalt can be rapidly predicted, a tedious bending beam rheometer test is not needed, and the test efficiency is greatly improved. The method also has the characteristics of low sample demand, simple operation, accurate result and the like, can be used for rapidly predicting the low-temperature performance of the laboratory asphalt, and also can be applied to asphalt extracted from a pavement core sample, so that the purpose of rapidly obtaining the low-temperature performance of the asphalt is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of road engineering, and in particular to a method for quickly predicting the low-temperature performance of asphalt based on DSR. Background Art

[0002] Low-temperature cracking of asphalt pavements is a common form of pavement failure. Its formation mechanism primarily stems from the shrinkage stress of the asphalt mixture exceeding the material's inherent tensile strength during a sudden temperature drop. Research has shown that asphalt's low-temperature rheological properties are a key factor influencing the crack resistance of asphalt pavements. When the pavement's service temperature falls significantly below the asphalt's low-temperature tolerance, asphalt pavements are highly susceptible to low-temperature cracking. Therefore, accurately characterizing asphalt's low-temperature properties and applying them to appropriate engineering scenarios is crucial for improving the performance and extending the service life of asphalt pavements.

[0003] At present, my country uses three major indicators, namely needle penetration, ductility, and softening point, to evaluate and grade asphalt performance. However, the test temperature range of this grading method is usually 5-90°C, which fails to cover the low temperature range of the service environment of asphalt pavement. The American AASHTO specification proposes a PG grading method to determine the high and low temperature performance of asphalt. Among them, a bending beam rheometer (BBR) is used to determine the low temperature performance grade of asphalt. However, the BBR test has disadvantages such as complex sample preparation, cumbersome procedures, and large sample requirements, which reduce the efficiency of asphalt low temperature performance testing. At the same time, the high cost of purchasing BBR equipment is also a major constraint affecting the characterization of asphalt low temperature performance through the PG grading method. It can be seen that there is an urgent need to develop a fast and efficient method for characterizing asphalt low temperature performance.

[0004] Patent CN119023455A discloses a method for predicting the low-temperature performance of asphalt using DSR, but this method requires relatively complex master curve fitting and linear viscoelastic conversion, which increases the computational workload; Patent CN118329656A discloses a method for determining the low-temperature performance of asphalt through a DSR test in ramp mode, but this method still obtains data such as the complex modulus in the DSR test and does not achieve the prediction of low-temperature performance parameters under the current standards, making it difficult to promote; Patent CN117272580A discloses a method for predicting the low-temperature performance of DSR. Although this method can simplify the BBR test operation process and more accurately predict the low-temperature performance of asphalt, it involves viscoelastic calculations for frequency domain and time domain conversion, which increases the difficulty of actual calculation operations. In response to the above technical drawbacks, a method for quickly predicting the low-temperature performance of asphalt based on dynamic shear rheometer (DSR) is proposed. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention provides a method for quickly predicting the low-temperature performance of asphalt based on DSR, which can realize the rapid prediction of the low-temperature performance of asphalt and has the advantages of small sample requirement, simple test steps, convenient and accurate calculation, etc.

[0006] To achieve the above object, the present invention provides the following technical solution: a method for quickly predicting the low-temperature performance of asphalt based on DSR, comprising the following steps:

[0007] S1. Prepare asphalt sample;

[0008] S2. Conduct a linear amplitude sweep test on the asphalt sample to determine its linear viscoelastic strain range;

[0009] S3. Select the temperature corresponding to the bending beam rheometer test, perform a temperature-frequency sweep test on the asphalt sample, and obtain the dynamic modulus and phase angle at different temperatures and frequencies;

[0010] S4. Fitting the acquired dynamic modulus and phase angle data using a master curve model to obtain a dynamic modulus master curve and a phase angle master curve;

[0011] S5. Based on the asphalt low-temperature performance prediction model, calculate the low-temperature performance evaluation parameters, namely the creep stiffness modulus and the creep stiffness change rate;

[0012] S6. Evaluate and analyze the prediction results based on the low-temperature performance grading evaluation standard to obtain the low-temperature performance grade of the measured asphalt sample.

[0013] Preferably, in step S1, the asphalt sample is cylindrical, with specific dimensions of: 4 mm in diameter and 2 mm in height.

[0014] Preferably, in step S2, the test temperature of the linear amplitude sweep test is -24°C, and the test frequency is 1 Hz.

[0015] Preferably, in step S3, the temperature corresponding to the bending beam rheometer test is selected with a gradient of 6°C, starting from -12°C and ending at -24°C, that is, the test temperatures are -12°C, -18°C, and -24°C; the test frequency is set to 0.01Hz~1Hz; the strain size is set according to the determined linear viscoelastic strain range.

[0016] Preferably, in step S4, the master curve model is selected from the group consisting of a Sigmoidal model, a CAM model, a CA model, and a 2S2P1D model.

[0017] Preferably, in step S5, the calculation formula of the asphalt low temperature performance prediction model is:

[0018] S=1.9395*G *(ω)| ω＝0.032Hz

[0019] m=0.012*δ(ω)| ω＝0.032Hz

[0020] Where S is the creep modulus; m is the creep rate of change; G * (ω) represents the dynamic modulus at a certain frequency; δ(ω) represents the phase angle at a certain frequency.

[0021] Preferably, in step S6, the evaluation and analysis standard of the prediction result is: determine the lowest temperature that satisfies both S≤300MPa and m≥0.3, and record the temperature 10°C lower than this temperature as the low-temperature performance grade of the asphalt sample.

[0022] The present invention provides a method for quickly predicting the low-temperature performance of asphalt based on DSR, which has the following advantages compared with the existing technology:

[0023] The proposed method for predicting asphalt's low-temperature performance significantly reduces the amount of asphalt used in testing. Conventional BBR testing requires approximately 30g of asphalt, but this method significantly reduces this amount, requiring only 1g of asphalt per test. Test results at multiple temperatures can be obtained, significantly improving testing efficiency and facilitating low-temperature performance testing of asphalt core samples taken from pavement. Furthermore, the proposed method avoids tedious viscoelastic mechanical calculations and rapidly obtains low-temperature performance evaluation indicators for asphalt through a convenient conversion formula, simplifying the calculation process and enhancing the method's applicability. Rapid prediction of asphalt's low-temperature performance through this method provides a reference for selecting asphalt materials for real-world projects, thereby improving the service life of asphalt pavements and extending their service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0025] Figure 1 Flow chart of the test method of the present invention;

[0026] Figure 2 The figure shows the predicted results and measured results of the creep stiffness modulus of asphalt of the present invention;

[0027] Figure 3 This is a graph showing the predicted and measured results of the creep stiffness modulus change rate of asphalt according to the present invention;

[0028] Figure 4 This is a diagram showing the predicted and measured results of the low-temperature performance grade of the asphalt of the present invention;

[0029] Figure 5 The dynamic modulus master curve and phase angle master curve of Example 1 of the present invention;

[0030] Figure 6 The dynamic modulus master curve and phase angle master curve of Example 2 of the present invention;

[0031] Figure 7 These are the dynamic modulus master curve and phase angle master curve of Example 3 of the present invention. DETAILED DESCRIPTION

[0032] The following examples illustrate the implementation methods of the present application in detail, so that the implementation process of how the present application applies technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0033] Example 1

[0034] A method for quickly predicting the low-temperature performance of asphalt based on DSR includes the following steps:

[0035] S1. Prepare an asphalt sample. In this embodiment, an asphalt sample prepared in the laboratory is used. The type of asphalt used is 70# asphalt. The sample is cylindrical with the following dimensions: diameter 4 mm, height 2 mm.

[0036] S2. Perform a linear amplitude sweep test on the asphalt sample, control the test temperature of the linear amplitude sweep test to -24°C and the test frequency to 1 Hz, and determine its linear viscoelastic strain range.

[0037] S3. Select the temperature corresponding to the bending beam rheometer test, that is, -12°C, -18°C, and -24°C as the test temperature, 0.01 Hz to 1 Hz as the test frequency, and control the strain size to 0.03%. Perform a temperature-frequency sweep test on the asphalt sample to obtain the dynamic modulus and phase angle at different temperatures and frequencies;

[0038] S4. Fitting the acquired dynamic modulus and phase angle data through a master curve model, wherein the master curve model selected is a CAM model, to obtain a dynamic modulus master curve and a phase angle master curve;

[0039] S5. Based on the asphalt low-temperature performance prediction model, calculate the low-temperature performance evaluation parameters, namely the creep stiffness modulus and the creep stiffness change rate; wherein the calculation formula of the asphalt low-temperature performance prediction model is:

[0040] S=1.9395*G * (ω)| ω＝0.032Hz

[0041] m=0.012*δ(ω)| ω＝0.032Hz

[0042] Where S is the creep modulus; m is the creep rate of change; G * (ω) represents the dynamic modulus at a certain frequency; δ(ω) represents the phase angle at a certain frequency.

[0043] S6. Evaluate and analyze the predicted results according to the low-temperature performance grading evaluation standard to obtain the low-temperature performance grade of the measured asphalt sample. The evaluation and analysis standard for the predicted results is as follows: determine the lowest temperature that satisfies both S ≤ 300 MPa and m ≥ 0.3. The temperature 10°C lower than this temperature is recorded as the low-temperature performance grade of the asphalt sample.

[0044] Example 2

[0045] A method for quickly predicting the low-temperature performance of asphalt based on DSR includes the following steps:

[0046] S1. Prepare an asphalt sample. In this embodiment, an asphalt sample prepared in the laboratory is used. The type of asphalt used is 90# asphalt. The sample is cylindrical with the following dimensions: diameter 4 mm, height 2 mm.

[0047] S2. Perform a linear amplitude sweep test on the asphalt sample, control the test temperature of the linear amplitude sweep test to -24°C and the test frequency to 1 Hz, and determine its linear viscoelastic strain range.

[0048] S3. Select the temperature corresponding to the bending beam rheometer test, that is, -12°C, -18°C, and -24°C as the test temperature, 0.01 Hz to 1 Hz as the test frequency, and control the strain size to 0.03%. Perform a temperature-frequency sweep test on the asphalt sample to obtain the dynamic modulus and phase angle at different temperatures and frequencies;

[0049] S4. Fitting the acquired dynamic modulus and phase angle data through a master curve model, wherein the master curve model selected is a CAM model, to obtain a dynamic modulus master curve and a phase angle master curve;

[0050] S5. Based on the asphalt low-temperature performance prediction model, calculate the low-temperature performance evaluation parameters, namely the creep stiffness modulus and the creep stiffness change rate; wherein the calculation formula of the asphalt low-temperature performance prediction model is:

[0051] S=1.9395*G * (ω)| ω＝0.032Hz

[0052] m=0.012*δ(ω)| ω＝0.032Hz

[0053] Where S is the creep modulus; m is the creep rate of change; G *(ω) represents the dynamic modulus at a certain frequency; δ(ω) represents the phase angle at a certain frequency.

[0054] S6. Evaluate and analyze the predicted results according to the low-temperature performance grading evaluation standard to obtain the low-temperature performance grade of the measured asphalt sample. The evaluation and analysis standard for the predicted results is as follows: determine the lowest temperature that satisfies both S ≤ 300 MPa and m ≥ 0.3. The temperature 10°C lower than this temperature is recorded as the low-temperature performance grade of the asphalt sample.

[0055] Example 3

[0056] A method for quickly predicting the low-temperature performance of asphalt based on DSR includes the following steps:

[0057] S1. Prepare an asphalt sample. The asphalt sample in this embodiment is obtained by extracting a pavement core specimen. The asphalt type is SBS modified asphalt. The sample is cylindrical with the following dimensions: 4 mm in diameter and 2 mm in height.

[0058] S2. Perform a linear amplitude sweep test on the asphalt sample, control the test temperature of the linear amplitude sweep test to -24°C and the test frequency to 1 Hz, and determine its linear viscoelastic strain range.

[0059] S3. Select the temperature corresponding to the bending beam rheometer test, i.e., -12°C, -18°C, and -24°C as the test temperature, 0.01 Hz to 1 Hz as the test frequency, and control the strain size to 0.02%. Perform a temperature-frequency sweep test on the asphalt sample to obtain the dynamic modulus and phase angle at different temperatures and frequencies.

[0060] S4. Fitting the acquired dynamic modulus and phase angle data through a master curve model, wherein the master curve model selected is a CAM model, to obtain a dynamic modulus master curve and a phase angle master curve;

[0061] S5. Based on the asphalt low-temperature performance prediction model, calculate the low-temperature performance evaluation parameters, namely the creep stiffness modulus and the creep stiffness change rate; wherein the calculation formula of the asphalt low-temperature performance prediction model is:

[0062] S=1.9395*G * (ω)| ω＝0.032Hz

[0063] m=0.012*δ(ω)| ω＝0.032Hz

[0064] Where S is the creep modulus; m is the creep rate of change; G * (ω) represents the dynamic modulus at a certain frequency; δ(ω) represents the phase angle at a certain frequency.

[0065] S6. Evaluate and analyze the predicted results according to the low-temperature performance grading evaluation standard to obtain the low-temperature performance grade of the measured asphalt sample. The evaluation and analysis standard for the predicted results is as follows: determine the lowest temperature that satisfies both S ≤ 300 MPa and m ≥ 0.3. The temperature 10°C lower than this temperature is recorded as the low-temperature performance grade of the asphalt sample.

[0066] Verification

[0067] 1. The low-temperature performance evaluation parameters obtained in Examples 1-3, creep stiffness modulus and creep stiffness change rate, were used to obtain the actual low-temperature performance results of the corresponding samples through the BBR test. All results are summarized in the table below.

[0068] Table 1 Low temperature performance of asphalt

[0069]

[0070] From the table results and combine Figure 2 、 Figure 3 It can be seen that the method for quickly predicting the low-temperature performance of asphalt based on DSR proposed in the present invention has accurate prediction results.

[0071] According to the low temperature performance grade evaluation standard, the low temperature performance grade of asphalt is obtained and the results are plotted on Figure 4 From the results, it can be seen that the low-temperature performance grade prediction accuracy of the present invention can reach 100%. Through the present invention, the low-temperature performance of asphalt can be quickly and accurately predicted, providing a reference for selecting suitable asphalt materials in actual projects.

[0072] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for quickly predicting the low-temperature performance of asphalt based on DSR, characterized in that: The following steps are involved: S1. Prepare asphalt sample; S2. Conduct a linear amplitude sweep test on the asphalt sample to determine its linear viscoelastic strain range; S3. Select the temperature corresponding to the bending beam rheometer test, perform a temperature-frequency sweep test on the asphalt sample, and obtain the dynamic modulus and phase angle at different temperatures and frequencies; S4. Fitting the acquired dynamic modulus and phase angle data using a master curve model to obtain a dynamic modulus master curve and a phase angle master curve; S5. Based on the asphalt low-temperature performance prediction model, calculate the low-temperature performance evaluation parameters, namely the creep stiffness modulus and the creep stiffness change rate; S6. Evaluate and analyze the prediction results based on the low-temperature performance grading evaluation standard to obtain the low-temperature performance grade of the measured asphalt sample.

2. The method for rapidly predicting low-temperature performance of asphalt based on DSR according to claim 1, characterized in that: In step S1, the asphalt sample is cylindrical, with specific dimensions of 4 mm in diameter and 2 mm in height.

3. The method for rapidly predicting low-temperature performance of asphalt based on DSR according to claim 1, characterized in that: In step S2, the test temperature of the linear amplitude sweep test is -24°C and the test frequency is 1 Hz.

4. The method for rapidly predicting low-temperature performance of asphalt based on DSR according to claim 1, characterized in that: In step S3, the temperature corresponding to the bending beam rheometer test is selected with a gradient of 6°C, starting from -12°C and ending at -24°C, that is, the test temperatures are -12°C, -18°C, and -24°C; the test frequency is set to 0.01Hz~1Hz; the strain size is set according to the determined linear viscoelastic strain range.

5. The method for rapidly predicting low-temperature performance of asphalt based on DSR according to claim 1 is characterized in that: In step S4, the master curve model is selected from the Sigmoidal model, the CAM model, the CA model and the 2S2P1D model.

6. The method for rapidly predicting low-temperature performance of asphalt based on DSR according to claim 1, characterized in that: In step S5, the calculation formula of the asphalt low temperature performance prediction model is: S=1.9395*G * (oh)| ω＝0.032Hz m=0.012*δ(ω)| ω＝0.032Hz Where S is the creep modulus; m is the creep rate of change; G * (ω) represents the dynamic modulus at a certain frequency; δ(ω) represents the phase angle at a certain frequency.

7. The method for rapidly predicting low-temperature performance of asphalt based on DSR according to claim 1, characterized in that: In step S6, the evaluation and analysis standard of the prediction results is: determine the lowest temperature that satisfies both S≤300MPa and m≥0.3, and record the temperature 10°C lower than this temperature as the low-temperature performance grade of the asphalt sample.

Images