A method and system for evaluating the influence of physical hardening on the performance of asphalt materials

Abstract

This invention relates to the field of low-temperature performance characterization technology for asphalt materials, specifically to a method and system for evaluating the impact of physical hardening on the performance of asphalt materials. The method includes the following steps: obtaining the stiffness modulus and stiffness modulus change rate at different isothermal storage times under multiple test temperatures; obtaining stiffness modulus fitting parameters using a four-parameter saturated growth model fitted to the stiffness modulus, and obtaining stiffness modulus change rate fitting parameters using an exponential-logarithmic mixed model fitted to the stiffness modulus change rate; obtaining the physical hardening response rate and physical hardening rate using the stiffness modulus fitting parameters and the stiffness modulus change rate fitting parameters, respectively; obtaining the stiffness modulus critical temperature loss value and relaxation critical temperature loss value based on the stiffness modulus, the stiffness modulus change rate, and the low-temperature temperature loss model; and quantifying the response rate and degree of asphalt materials to physical hardening using multiple quantitative indicators.

Description

Technical Field

[0001] This invention relates to the field of low-temperature performance characterization technology for asphalt materials, specifically to a method and system for evaluating the impact of physical hardening on the performance of asphalt materials. Background Technology

[0002] Asphalt is a typical viscoelastic material, and its mechanical properties and state vary significantly with temperature. At low temperatures, the movement of asphalt molecules is restricted, and its properties are dominated by elasticity to resist deformation, while ductility decreases and brittleness significantly increases. Asphalt materials used in cold regions require good low-temperature performance, which depends on the accuracy of characterization methods and evaluation indicators. Researchers have observed that asphalt materials exhibit significant non-chemically damaging mechanical degradation after prolonged storage at low temperatures. At the macroscopic mechanical level, this is manifested as modulus increase, relaxation performance decline, and a significant decrease in the material's low-temperature performance, which is closely related to time and temperature; this is termed "physical hardening." Studies show that ignoring the characterization results of physical hardening will significantly overestimate the low-temperature performance of asphalt materials, posing a significant risk to the design and healthy service of asphalt pavements in regions with long cold seasons and perennially cold conditions, potentially leading to premature cracking within the designed service life. Therefore, the physical hardening characteristics of asphalt materials cannot be ignored in low-temperature performance characterization, and the material's response rate and extent to physical hardening need to be further clarified.

[0003] Currently, there are insufficient methods for characterizing the response rate and extent of asphalt materials to physical hardening. The concept of "physical hardening rate," proposed by Tabatabaee, is widely used; however, it only provides a qualitative characterization and cannot quantify the response of asphalt materials to physical hardening. The lack of effective characterization methods and evaluation indicators is one of the important reasons why physical hardening is often overlooked in practical engineering. Summary of the Invention

[0004] To address the shortcomings of existing methods and the needs of practical applications, and in order to solve the aforementioned problems, this invention provides a method for evaluating the impact of physical hardening on the properties of asphalt materials, comprising the following steps:

[0005] The stiffness modulus and stiffness modulus change rate were obtained at different isothermal storage times under multiple test temperatures. The stiffness modulus fitting parameters were obtained using a four-parameter saturated growth model, and the stiffness modulus change rate fitting parameters were obtained using an exponential-logarithmic mixture model. The physical hardening response rate, physical hardening rate, and physical hardening rate of the stiffness modulus and stiffness modulus change rate were obtained respectively using the stiffness modulus fitting parameters and the stiffness modulus change rate fitting parameters. A low-temperature temperature loss model was constructed, and the critical temperature loss value and relaxation critical temperature loss value of the stiffness modulus were obtained based on the stiffness modulus, the stiffness modulus change rate, and the low-temperature temperature loss model. The impact of physical hardening on the properties of asphalt materials was evaluated by combining the physical hardening response rate, the critical temperature loss value of the stiffness modulus, the physical hardening rate of the stiffness modulus, the physical hardening rate of the stiffness modulus, and the relaxation critical temperature loss value.

[0006] This invention provides a numerical quantitative evaluation of the impact of physical hardening on the properties of asphalt materials, offering theoretical support for the characterization and development of asphalt materials in cold regions. Mathematical function models are proposed from two perspectives: stiffness modulus and stiffness modulus change rate. These models quantify the degree and rate of response to physical hardening, providing precise guidance for the selection, characterization, and development of asphalt pavement materials in cold regions. Furthermore, a critical temperature loss value index is proposed, directly reflecting the low-temperature performance loss of asphalt materials under physical hardening, thus providing an evaluation method for the selection and development of asphalt pavement materials in cold regions.

[0007] Optionally, the stiffness modulus fitting parameters are obtained by using the four-parameter saturated growth model fitted with the stiffness modulus, satisfying the following formula:

[0008] ,in, This represents the stiffness modulus corresponding to a loading time of 60 seconds under isothermal storage conditions of t hours. This represents the fitting parameters for the stiffness modulus, and This represents the stable value of the stiffness modulus corresponding to an infinitely long storage time at the target temperature. This invention represents the isothermal storage time. It precisely characterizes the dynamic changes in stiffness modulus during physical hardening. For example, the initial stiffness modulus reflects the material's initial state, the saturated stiffness modulus reflects the hardening limit, and the growth rate and delay time parameters reveal the hardening speed and hysteresis characteristics. These parameters provide a foundation for subsequent calculations of the physical hardening response rate and the physical hardening rate of stiffness modulus, making the impact of physical hardening on asphalt properties quantifiable. They also provide a unified standard for comparing the physical hardening properties of different asphalt materials, facilitating accurate evaluation of material performance.

[0009] Optionally, the fitting parameters for the rate of change of the stiffness modulus are obtained by fitting an exponential-logarithmic mixture model using the rate of change of the stiffness modulus, satisfying the following formula: ,in, This represents the rate of change of stiffness modulus corresponding to a loading time of 60 seconds under an isothermal storage time of t hours. The fitting parameters represent the rate of change of the stiffness modulus. This indicates the isothermal storage time. This invention accurately captures the decay law of the stiffness modulus change rate during physical hardening, providing a basis for calculating the physical hardening response rate and the physical hardening rate corresponding to the stiffness modulus change rate. It can quantify the degree and rate of decay of the m-value due to physical hardening, and also determine the m-value saturation state. This lays the foundation for comparing the physical hardening performance of different asphalt materials and helps to comprehensively evaluate the impact of physical hardening on the low-temperature relaxation performance of asphalt.

[0010] Optionally, the physical hardening response rate corresponding to the stiffness modulus is obtained through the stiffness modulus fitting parameters, satisfying the following formula: ,in, This represents the response rate of the stiffness modulus to physical hardening under isothermal storage time t. This represents the fitting parameters for the stiffness modulus. This indicates the isothermal storage time. The physical hardening response rate corresponding to the stiffness modulus directly reflects how quickly the stiffness modulus changes with physical hardening; a larger value indicates that the asphalt hardens faster due to physical hardening. It provides a key indicator for quantifying the physical hardening process, can be used to compare the dynamic differences of different asphalt materials during the physical hardening process, and also provides an important basis for subsequent comprehensive evaluation of the impact of physical hardening on asphalt performance. It helps to accurately determine the performance degradation rate and potential risks of asphalt materials during use.

[0011] Optionally, the physical hardening response rate corresponding to the stiffness modulus change rate is obtained through the stiffness modulus change rate fitting parameters, satisfying the following formula: ,in, This represents the rate of change of stiffness modulus in response to physical hardening under isothermal storage time t. The fitting parameters represent the rate of change of the stiffness modulus. This represents the isothermal storage time. The physical hardening response rate corresponding to the rate of change of stiffness modulus directly reflects how quickly the rate of change of stiffness modulus decays with physical hardening; the larger the value, the more rapidly the m value decreases. This parameter quantifies the degradation rate of asphalt's low-temperature relaxation ability, providing a basis for comparing the differences in relaxation performance degradation among different asphalt materials during physical hardening. It also provides an important indicator for comprehensively evaluating the impact of physical hardening on asphalt's low-temperature crack resistance, helping to accurately determine the cracking risk caused by the decline in relaxation performance during material use.

[0012] Optionally, the physical hardening rate of the stiffness modulus can be obtained through the stiffness modulus fitting parameters, satisfying the following formula: ,in, Indicates the stiffness modulus and physical hardening rate. This represents the stiffness modulus corresponding to a loading time of 60 seconds under isothermal storage conditions of t hours. This represents the stiffness modulus corresponding to a loading time of 60 seconds under an isothermal storage time of 1 hour. This represents the stable stiffness modulus value corresponding to an infinitely long storage time at the target temperature. Based on initial and saturated stiffness modulus calculations, this invention can intuitively reflect the relative increase in stiffness modulus caused by physical hardening. This index quantifies the degree of stiffness enhancement in asphalt materials due to physical hardening, providing a basis for comparing the final impact of physical hardening on different asphalt materials. It is also a key parameter for comprehensively evaluating the impact of physical hardening on asphalt performance, helping to assess the risks such as decreased low-temperature crack resistance that may arise from increased stiffness during long-term use.

[0013] Optionally, the rate of change of stiffness modulus and the physical hardening rate are obtained by fitting the stiffness modulus change rate parameters, satisfying the following formula: ,in, This represents the rate of change of stiffness modulus and the rate of physical hardening. This represents the rate of change of stiffness modulus corresponding to a loading time of 60 seconds under an isothermal storage time of 1 hour. This represents the rate of change of stiffness modulus corresponding to a loading time of 60 seconds under an isothermal storage time of t hours. This represents the fitting parameter for the rate of change of stiffness modulus.

[0014] Optionally, a low-temperature temperature loss model is constructed. Based on the stiffness modulus, the rate of change of the stiffness modulus, and the low-temperature temperature loss model, the critical temperature loss value of the stiffness modulus is obtained, satisfying the following formula: , in, This represents the critical temperature for stiffness modulus after isothermal storage for i hours. Indicates the test temperature. express The stiffness modulus under the given conditions, and ≥300Mpa express The stiffness modulus under the given conditions, and ≤300MPa This represents the loss of stiffness modulus at the critical temperature under physical hardening. This represents the critical temperature of the stiffness modulus corresponding to an infinitely long isothermal storage time. This indicates the critical temperature of stiffness modulus corresponding to a 1-hour isothermal storage time.

[0015] Optionally, a low-temperature temperature loss model is constructed, and based on the stiffness modulus, the rate of change of the stiffness modulus, and the low-temperature temperature loss model, the relaxation critical temperature loss value is obtained, satisfying the following formula: , in, This represents the relaxation critical temperature after isothermal storage for i hours. Indicates the test temperature. express Rate of change of stiffness modulus under certain conditions express Rate of change of stiffness modulus under certain conditions This represents the loss value at the relaxation critical temperature under physical hardening. This represents the relaxation critical temperature corresponding to an infinitely long isothermal storage time. This represents the relaxation critical temperature corresponding to a 1-hour isothermal storage time. This invention constructs a low-temperature temperature loss model and obtains two critical temperature loss values, correlating stiffness modulus, the rate of change of stiffness modulus, and temperature to quantify the relationship between performance degradation at low temperatures and temperature. The critical values ​​directly reflect the degree of temperature loss when asphalt reaches its performance critical state (e.g., stiffness 300 MPa, m value 0.3), providing a basis for judging the low-temperature crack resistance and relaxation performance limits of materials, and also providing a standard for comparing the low-temperature performance of different asphalts after physical hardening, thus helping to accurately assess the risk of material failure caused by temperature changes in engineering projects.

[0016] Secondly, to efficiently execute the method for evaluating the impact of physical hardening on asphalt material performance provided by this invention, this invention also provides a system for evaluating the impact of physical hardening on asphalt material performance, including a processor, an input device, an output device, and a memory. The processor, input device, output device, and memory are interconnected. The memory stores a computer program containing program instructions. The processor is configured to call the program instructions to execute the method for evaluating the impact of physical hardening on asphalt material performance as described in the first aspect of this invention. The system for evaluating the impact of physical hardening on asphalt material performance provided by this invention has a compact structure and stable performance, and can stably execute the method for evaluating the impact of physical hardening on asphalt material performance provided by this invention, further enhancing the overall applicability and practical application capability of this invention. Attached Figure Description

[0017] Figure 1 A flowchart of a method for evaluating the impact of physical hardening on the properties of asphalt materials provided in an embodiment of the present invention;

[0018] Figure 2This is a schematic diagram of a four-parameter saturated growth model provided in an embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram of an exponential-logarithmic mixture model provided in an embodiment of the present invention;

[0020] Figure 4 This is a schematic diagram of the stiffness modulus function for different isothermal storage times provided in embodiments of the present invention;

[0021] Figure 5 This is a schematic diagram of the rate of change of stiffness modulus over different isothermal storage times provided in embodiments of the present invention.

[0022] Figure 6 A schematic diagram illustrating the response rate of stiffness modulus to physical hardening provided in an embodiment of the present invention;

[0023] Figure 7 A schematic diagram illustrating the response rate of the stiffness modulus change rate to physical hardening, provided in an embodiment of the present invention;

[0024] Figure 8 This is a framework diagram of an evaluation system for the impact of physical hardening on the performance of asphalt materials, provided in an embodiment of the present invention. Detailed Implementation

[0025] Specific embodiments of the present invention will now be described in detail. It should be noted that the embodiments described herein are for illustrative purposes only and are not intended to limit the invention. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to practice the invention. In other instances, well-known circuits, software, or methods have not been specifically described to avoid obscuring the invention.

[0026] Throughout this specification, references to "an embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment of the invention. Therefore, the phrases "in an embodiment," "in an embodiment," "an example," or "an example" appearing in various places throughout the specification do not necessarily refer to the same embodiment or example. Furthermore, specific features, structures, or characteristics can be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. Moreover, those skilled in the art will understand that the illustrations provided herein are for illustrative purposes and are not necessarily drawn to scale.

[0027] Please see Figure 1 To address the above problems, this invention provides a method for evaluating the impact of physical hardening on the properties of asphalt materials, such as... Figure 1 As shown, in one embodiment, the method includes the following steps:

[0028] S1. Obtain the stiffness modulus and the rate of change of stiffness modulus for different isothermal storage times at multiple test temperatures.

[0029] First, prepare the bending beam rheometer specimens according to the requirements of AASHTO T313-06. Select a bending beam rheometer that meets the requirements of AASHTO T313-06, and choose the test temperature range based on the properties of the asphalt material. ≤ ≤ , ≤ ≤ ,in, , They represent temperature. , stiffness modulus under the given conditions , They represent temperature. , Rate of change of stiffness modulus under certain conditions;

[0030] Once the temperature control bath of the bending beam rheometer reaches the target temperature, the specimen is placed in the temperature control bath for isothermal storage, and the time is recorded.

[0031] Set a series of isothermal storage times, requiring that the isothermal storage time within 24 hours be set more intensively, while the storage time after 24 hours can be appropriately relaxed;

[0032] After the specimen storage time reaches the set requirements, the test is carried out according to the test procedure of AASHTO T313-06, and the stiffness modulus S(60) and stiffness modulus change rate m(60) corresponding to 60 s (seconds) at each test temperature are calculated.

[0033] The basic experimental equipment of this invention still adopts the current mainstream bending beam rheometer, without the need to purchase additional low-temperature loading equipment, and the test operation follows the current standard requirements. Therefore, this invention has wide applicability and helps to promote the consideration of physical hardening effect in practical engineering.

[0034] S2. Obtain the stiffness modulus fitting parameters using the four-parameter saturated growth model of the stiffness modulus fitting, and obtain the stiffness modulus change rate fitting parameters using the exponential-logarithmic mixed model of the stiffness modulus change rate fitting.

[0035] Specifically, the stiffness modulus fitting four-parameter saturated growth model is used to obtain the stiffness modulus fitting parameters, which satisfy the following formula:

[0036] ,in, This represents the stiffness modulus corresponding to a loading time of 60 seconds under isothermal storage conditions of t hours. This represents the fitting parameters for the stiffness modulus, and This represents the stable value of the stiffness modulus corresponding to an infinitely long storage time at the target temperature. Indicates isothermal storage time. Please refer to [link / reference]. Figure 2 Based on model parameters and numerical results, the degree of response of the stiffness modulus of asphalt materials to the physical hardening effect is quantitatively characterized.

[0037] The fitting parameters for the rate of change of the stiffness modulus are obtained by fitting an exponential-logarithmic mixture model using the rate of change of the stiffness modulus, satisfying the following formula: ,in, This represents the rate of change of stiffness modulus corresponding to a loading time of 60 seconds under an isothermal storage time of t hours. The fitting parameters represent the rate of change of the stiffness modulus. Indicates isothermal storage time. Please refer to [link / reference]. Figure 3 The response of the stiffness modulus change rate of asphalt material to the physical hardening effect is quantitatively characterized based on model parameters and numerical results. The physical meaning of parameter (f+g) is the m(60) stable value corresponding to an infinite storage time at the target temperature.

[0038] S3. Obtain the physical hardening response rate corresponding to the stiffness modulus and the stiffness modulus change rate, as well as the physical hardening rate of the stiffness modulus and the physical hardening rate of the stiffness modulus change rate, respectively, using the stiffness modulus fitting parameters and the stiffness modulus change rate fitting parameters.

[0039] Specifically, the physical hardening response rate corresponding to the stiffness modulus is obtained through the stiffness modulus fitting parameters, satisfying the following formula: ,in, This represents the response rate of the stiffness modulus to physical hardening under isothermal storage time t. This represents the fitting parameters for the stiffness modulus. The isothermal storage time is represented by t. The fitting result of the above four-parameter saturated growth model parameters is substituted into the first derivative of the model to characterize the physical hardening response rate corresponding to the stiffness modulus at the isothermal storage time t.

[0040] By fitting the stiffness modulus change rate parameters, the physical hardening response rate corresponding to the stiffness modulus change rate is obtained, satisfying the following formula: ,in, This represents the rate of change of stiffness modulus in response to physical hardening under isothermal storage time t. The fitting parameters represent the rate of change of the stiffness modulus. The isothermal storage time is represented by t. Substituting the fitting results of the above exponential-logarithmic mixed model parameters into the first derivative of the model, we can characterize the physical hardening response rate corresponding to the rate of change of stiffness modulus at isothermal storage time t.

[0041] Furthermore, the physical hardening rate of the stiffness modulus is obtained through the stiffness modulus fitting parameters, satisfying the following formula: ,in, Indicates the stiffness modulus and physical hardening rate. This represents the stiffness modulus corresponding to a loading time of 60 seconds under isothermal storage conditions of t hours. This represents the stiffness modulus corresponding to a loading time of 60 seconds under an isothermal storage time of 1 hour. This represents the stable value of the stiffness modulus corresponding to an infinitely long storage time at the target temperature. In this embodiment, the ratio of the increase in stiffness modulus at a certain isothermal storage time t to the increase in stiffness modulus corresponding to an infinitely long storage time is used to represent the degree of response of the stiffness modulus to physical hardening, i.e., the physical hardening rate of the stiffness modulus.

[0042] By fitting the stiffness modulus change rate parameters, the physical hardening rate of the stiffness modulus change rate is obtained, satisfying the following formula: ,in, This represents the rate of change of stiffness modulus and the rate of physical hardening. This represents the rate of change of stiffness modulus corresponding to a loading time of 60 seconds under an isothermal storage time of 1 hour. This represents the rate of change of stiffness modulus corresponding to a loading time of 60 seconds under an isothermal storage time of t hours. This represents the fitting parameter for the rate of change of stiffness modulus. In the embodiment, the ratio of the rate of change of stiffness modulus loss at a certain isothermal storage time t to the rate of change of stiffness modulus loss corresponding to an infinitely long storage time is used to represent the degree of response of the rate of change of stiffness modulus to physical hardening, i.e., the rate of change of stiffness modulus to physical hardening rate.

[0043] This invention proposes mathematical function models for both stiffness modulus and stiffness modulus change rate, quantifying their response to physical hardening and rate, which can accurately guide the selection, characterization, and material development of asphalt pavement in cold regions.

[0044] S4. Construct a low-temperature temperature loss model, and obtain the critical temperature loss value of the stiffness modulus and the critical temperature loss value of relaxation based on the stiffness modulus, the rate of change of the stiffness modulus, and the low-temperature temperature loss model.

[0045] In the embodiments, the present invention utilizes the critical temperature loss value To characterize the low-temperature temperature loss of asphalt materials, whether or not physical hardening is considered.

[0046] Specifically, a low-temperature temperature loss model is constructed. Based on the stiffness modulus, the rate of change of the stiffness modulus, and the low-temperature temperature loss model, the critical temperature loss value of the stiffness modulus is obtained, satisfying the following formula: , in, This represents the critical temperature for stiffness modulus after isothermal storage for i hours. Indicates the test temperature. express The stiffness modulus under the given conditions, and ≥300Mpa express The stiffness modulus under the given conditions, and ≤300MPa This represents the loss of stiffness modulus at the critical temperature under physical hardening. This represents the critical temperature of the stiffness modulus corresponding to an infinitely long isothermal storage time. This indicates the critical temperature of stiffness modulus corresponding to a 1-hour isothermal storage time.

[0047] Furthermore, a low-temperature temperature loss model is constructed. Based on the stiffness modulus, the rate of change of the stiffness modulus, and the low-temperature temperature loss model, the relaxation critical temperature loss value is obtained, satisfying the following formula: , in, This represents the relaxation critical temperature after isothermal storage for i hours. Indicates the test temperature. express Rate of change of stiffness modulus under certain conditions express Rate of change of stiffness modulus under certain conditions This represents the loss value at the relaxation critical temperature under physical hardening. This represents the relaxation critical temperature corresponding to an infinitely long isothermal storage time. This indicates the relaxation critical temperature corresponding to a 1-hour isothermal storage time.

[0048] This invention proposes a critical temperature loss value index, which directly reflects the loss of low-temperature grade of asphalt materials under physical hardening, providing an evaluation method for the selection and development of asphalt pavement materials in cold regions.

[0049] S5. Evaluate the impact of physical hardening on the properties of asphalt materials by combining the physical hardening response rate, the stiffness modulus critical temperature loss value, the stiffness modulus physical hardening rate, the stiffness modulus change rate physical hardening rate, and the relaxation critical temperature loss value.

[0050] In this embodiment, an evaluation index system is first established, with physical hardening response rate, stiffness modulus critical temperature loss value, stiffness modulus physical hardening rate, stiffness modulus change rate physical hardening rate, and relaxation critical temperature loss value as the core evaluation indexes.

[0051] Then, the weights of each indicator are determined. Based on the importance of each indicator to the performance of asphalt materials, the weight of each indicator is determined using methods such as the analytic hierarchy process (AHP) or expert scoring. For example, the critical temperature loss value of stiffness modulus and the critical temperature loss value of relaxation are directly related to the risk of low-temperature cracking of pavement and can be assigned higher weights.

[0052] Finally, a comprehensive evaluation calculation is performed. The measured or calculated values ​​of each indicator are standardized, and then weighted and summed to obtain a comprehensive evaluation index. Based on the magnitude of the comprehensive evaluation index, the impact of physical hardening on asphalt material performance is classified into levels (e.g., slight impact, moderate impact, severe impact), thus completing the evaluation of the impact of physical hardening.

[0053] For example, for 90# base asphalt produced by a certain company, the bending rheometer equipment is manufactured by Cannon Instrument Company of the United States. The temperature setting range is room temperature to 40°C, with an error of ±0.03°C. Anhydrous ethanol can be used as the refrigerant, and the test sample is stored isothermally in an anhydrous ethanol environment.

[0054] Implementation Example 1: Quantifying the degree and rate of physical hardening response of asphalt materials

[0055] Step 1: Clean the aluminum mold according to AASHTO T313-06 requirements, apply a layer of petroleum-based grease to the surface and assemble it for later use.

[0056] Step 2: Heat an appropriate amount of asphalt to 150℃ to eliminate heat history, then pour the asphalt into the mold. The pouring should be unidirectional and completed in one go, with the asphalt slightly exceeding the mold's height. Allow the mold filled with asphalt to cool naturally at room temperature for 45-60 minutes, then use a hot knife to cut off the excess asphalt.

[0057] Step 3: Set the target temperature of the bending beam rheometer to -18 ℃. Place the mold in the cooling chamber and cool it to -10 ℃ at a rate of 2 ℃ / min. After holding at this temperature for 10 min, remove the aluminum mold and transfer the specimen to the anhydrous ethanol solution in the bending beam rheometer for isothermal storage. Place multiple specimens according to the volume of the storage environment and record the placement time.

[0058] Step 4: Set a series of isothermal storage times of 1, 5, 9, 15, 24, 48, 72, and 96 hours. After reaching the corresponding isothermal storage time, perform a three-point bending load test on the sample and record the stiffness modulus corresponding to a 60-second loading time. and the rate of change of stiffness modulus (ih corresponds to the isothermal storage time mentioned above).

[0059] Step 5: Use a four-parameter saturated growth model and an exponential-logarithmic mixed model to respectively... and The model parameters were obtained through nonlinear fitting using Excel's Solver function. The fitting results are as follows: Figure 4 and 5 As shown.

[0060] Step 6: Calculate the stiffness modulus physical hardening rate and the stiffness modulus change rate physical hardening rate corresponding to any isothermal storage time, in order to quantify the degree of response to physical hardening. Some results are shown in Table 1.

[0061]

[0062] Table 1 Physical hardening rate corresponding to different isothermal storage times

[0063] Step 7: Substitute the parameters obtained from the above model fitting solution into the physical hardening response rate calculation model to characterize the response rate of physical hardening to any isothermal storage time. The results are as follows: Figure 6 and 7 As shown.

[0064] For the construction and maintenance of asphalt pavements in cold regions, a database of the degree and rate of physical hardening response of different asphalt materials can be established. Based on the engineering environment, actual needs, and material properties, suitable asphalt materials can be selected, or targeted development of asphalt materials can be carried out. Regarding asphalt material characterization, based on the laws governing the degree and rate of material response to physical hardening, the isothermal storage time of asphalt materials can be extended to improve the matching degree between indoor test characterization results and field tests.

[0065] Implementation Example 2: Quantifying the Low-Temperature Loss of Asphalt Materials under Physical Hardening

[0066] Step 1: Same as steps 1, 2, 3, 4 and 5 of Example 1.

[0067] Step 2: Set the target temperature of the bending beam rheometer to -24℃, and perform tests and data processing according to steps 3, 4 and 5 of Implementation Example 1 to obtain S(60) and m(60) corresponding to different isothermal storage times.

[0068] Step 3: Calculate the critical temperature loss index, the process is as follows:

[0069]

[0070]

[0071]

[0072]

[0073] In summary, the stiffness modulus and relaxation critical temperature loss of the 90# base asphalt used in the test after physical hardening were 2.92℃ and 4.67℃, respectively. These indicators should be fully considered in the selection and characterization of asphalt pavement materials in cold regions.

[0074] Please see Figure 8 In this embodiment, to efficiently execute the method for evaluating the impact of physical hardening on asphalt material performance provided by this invention, the present invention also provides a system for evaluating the impact of physical hardening on asphalt material performance, comprising: an input device, an output device, a processor, and a memory, wherein the input device, output device, processor, and memory are interconnected, and the memory contains program instructions for the steps of the method for evaluating the impact of physical hardening on asphalt material performance. The system for evaluating the impact of physical hardening on asphalt material performance provided by this invention has a compact structure and stable performance, and can stably execute the method for evaluating the impact of physical hardening on asphalt material performance provided by this invention, further enhancing the overall applicability and practical application capability of this invention.

[0075] In embodiments, the processor may be a Central Processing Unit (CPU), but it can also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor. Input devices can be used to acquire data information. Output devices can be used to output the results obtained by storing program instructions contained in a computer program in the memory provided by this invention. The memory may include read-only memory and random access memory, and provides instructions and data to the processor. A portion of the memory may also include non-volatile random access memory.

[0076] In one possible implementation, the memory may include a stored program area and a stored data area. The stored program area may store the operating system and applications required for at least one function; the stored data area may store data created during use. Furthermore, the memory may include read-only memory and random access memory, providing instructions and data to the processor. A portion of the memory may also include NVRAM. The memory stores the operating system and operating instructions, executable modules, or data structures, or subsets thereof, or extended sets thereof. The operating instructions may include various operation instructions for implementing various operations. The operating system may include various system programs for implementing various basic tasks and handling hardware-based tasks.

[0077] The embodiment also provides a storage medium storing a computer program, which, when executed by a processor, implements the steps of the above-described method for evaluating the impact of physical hardening on the performance of asphalt materials.

[0078] The storage medium can include various media that can store program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0079] This invention provides a numerical quantitative evaluation of the impact of physical hardening on the properties of asphalt materials, offering theoretical support for the characterization and development of asphalt materials in cold regions. Mathematical function models are proposed from two perspectives: stiffness modulus and stiffness modulus change rate. These models quantify the degree and rate of response to physical hardening, providing precise guidance for the selection, characterization, and development of asphalt pavement materials in cold regions. Furthermore, a critical temperature loss value index is proposed, directly reflecting the low-temperature performance loss of asphalt materials under physical hardening, thus providing an evaluation method for the selection and development of asphalt pavement materials in cold regions.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the present invention.

Claims

1. A method for evaluating the influence of physical hardening on the properties of asphalt materials, characterized in that, Includes the following steps: Obtain the stiffness modulus and the rate of change of stiffness modulus for different isothermal storage times at multiple test temperatures; The stiffness modulus fitting parameters are obtained by using the four-parameter saturated growth model of the stiffness modulus fitting, and the stiffness modulus change rate fitting parameters are obtained by using the exponential-logarithmic mixture model of the stiffness modulus change rate fitting. By using the stiffness modulus fitting parameters and the stiffness modulus change rate fitting parameters, the physical hardening response rates corresponding to the stiffness modulus and the stiffness modulus change rate, as well as the physical hardening rate of the stiffness modulus and the physical hardening rate of the stiffness modulus change rate, are obtained respectively. A low-temperature temperature loss model is constructed, and the critical temperature loss value of the stiffness modulus and the relaxation critical temperature loss value are obtained based on the stiffness modulus, the rate of change of the stiffness modulus, and the low-temperature temperature loss model. The impact of physical hardening on the properties of asphalt materials is evaluated by combining the physical hardening response rate, the stiffness modulus critical temperature loss value, the stiffness modulus physical hardening rate, the stiffness modulus change rate physical hardening rate, and the relaxation critical temperature loss value. The fitting parameters for the rate of change of the stiffness modulus are obtained by fitting an exponential-logarithmic mixture model using the rate of change of the stiffness modulus, satisfying the following formula: in, This represents the rate of change of stiffness modulus corresponding to a loading time of 60 seconds under an isothermal storage time of t hours. The fitting parameters represent the rate of change of the stiffness modulus. Indicates isothermal storage time; By fitting the stiffness modulus change rate parameters, the physical hardening response rate corresponding to the stiffness modulus change rate is obtained, satisfying the following formula: in, This represents the rate of change of stiffness modulus in response to physical hardening under isothermal storage time t. The fitting parameters represent the rate of change of the stiffness modulus. Indicates the isothermal storage time.

2. The method for evaluating the impact of physical hardening on the properties of asphalt materials according to claim 1, characterized in that, The stiffness modulus fitting parameters are obtained by fitting a four-parameter saturated growth model using the stiffness modulus, and satisfy the following formula: in, This represents the stiffness modulus corresponding to a loading time of 60 seconds under isothermal storage conditions of t hours. This represents the fitting parameters for the stiffness modulus, and This represents the stable value of the stiffness modulus corresponding to an infinitely long storage time at the target temperature. Indicates the isothermal storage time.

3. The method for evaluating the impact of physical hardening on the properties of asphalt materials according to claim 1, characterized in that, By using the stiffness modulus fitting parameters, the physical hardening response rate corresponding to the stiffness modulus is obtained, satisfying the following formula: in, This represents the response rate of the stiffness modulus to physical hardening under isothermal storage time t. This represents the fitting parameters for the stiffness modulus. Indicates the isothermal storage time.

4. The method for evaluating the impact of physical hardening on the properties of asphalt materials according to claim 1, characterized in that, The physical hardening rate of the stiffness modulus is obtained by using the stiffness modulus fitting parameters, which satisfies the following formula: in, Indicates the stiffness modulus and physical hardening rate. This represents the stiffness modulus corresponding to a loading time of 60 seconds under isothermal storage conditions of t hours. This represents the stiffness modulus corresponding to a loading time of 60 seconds under an isothermal storage time of 1 hour. This represents the stable value of the stiffness modulus corresponding to an infinitely long storage time at the target temperature.

5. The method for evaluating the impact of physical hardening on the properties of asphalt materials according to claim 1, characterized in that, By fitting the stiffness modulus change rate parameters, the physical hardening rate of the stiffness modulus change rate is obtained, satisfying the following formula: in, This represents the rate of change of stiffness modulus and the rate of physical hardening. This represents the rate of change of stiffness modulus corresponding to a loading time of 60 seconds under an isothermal storage time of 1 hour. This represents the rate of change of stiffness modulus corresponding to a loading time of 60 seconds under an isothermal storage time of t hours. This represents the fitting parameter for the rate of change of stiffness modulus.

6. The method for evaluating the impact of physical hardening on the properties of asphalt materials according to claim 1, characterized in that, A low-temperature temperature loss model is constructed. Based on the stiffness modulus, the rate of change of the stiffness modulus, and the low-temperature temperature loss model, the critical temperature loss value of the stiffness modulus is obtained, satisfying the following formula: in, This represents the critical temperature for stiffness modulus after isothermal storage for i hours. Indicates the test temperature. express The stiffness modulus under the given conditions, and ≥300Mpa express The stiffness modulus under the given conditions, and ≤300MPa This represents the loss of stiffness modulus at the critical temperature under physical hardening. This represents the critical temperature of the stiffness modulus corresponding to an infinitely long isothermal storage time. This indicates the critical temperature of stiffness modulus corresponding to a 1-hour isothermal storage time.

7. The method for evaluating the impact of physical hardening on the properties of asphalt materials according to claim 1, characterized in that, A low-temperature temperature loss model is constructed. Based on the stiffness modulus, the rate of change of the stiffness modulus, and the low-temperature temperature loss model, the relaxation critical temperature loss value is obtained, satisfying the following formula: in, This represents the relaxation critical temperature after isothermal storage for i hours. Indicates the test temperature. express Rate of change of stiffness modulus under certain conditions express Rate of change of stiffness modulus under certain conditions This represents the loss value at the relaxation critical temperature under physical hardening. This represents the relaxation critical temperature corresponding to an infinitely long isothermal storage time. This indicates the relaxation critical temperature corresponding to a 1-hour isothermal storage time.

8. A system for evaluating the impact of physical hardening on the properties of asphalt materials, characterized in that, The system for evaluating the impact of physical hardening on the performance of asphalt materials includes: an input device, an output device, a processor, and a memory, wherein the input device, output device, processor, and memory are interconnected, and the memory includes program instructions for executing the method for evaluating the impact of physical hardening on the performance of asphalt materials according to any one of claims 1-7.

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