Method and device for measuring low-temperature creep characteristic of asphalt mixture

Abstract

The invention provides a method and a device for measuring low-temperature creep characteristics of an asphalt mixture, and relates to the field of asphalt material analysis. The method comprises the following steps: cutting a target asphalt mixed test material according to a preset size; obtaining the cut standard trabecular test piece, and performing a trabecular bending damage test on the standard trabecular test piece according to a preset temperature to obtain a maximum load corresponding to the standard trabecular test piece; according to the maximum load, performing a gradual increasing creep load test on the standard small beam test piece according to a preset temperature, and calculating a first creep compliance corresponding to the standard small beam test piece; calculating a second creep compliance corresponding to the standard small beam test piece through a low-temperature creep characteristic evaluation model, carrying out consistency verification, and obtaining a verification result; and calculating the low-temperature creep property of the target asphalt mixed test material at the preset temperature according to the verification result and the dissipative energy ratio index. The problem that an existing evaluation result of the low-temperature creep characteristics is inaccurate is solved.

Description

Technical Field

[0001] The present application relates to the field of asphalt material analysis, and in particular to a method and device for determining low-temperature creep characteristics of asphalt mixtures. Background Art

[0002] Asphalt mixture is a viscoelastic material, and its low-temperature creep deformation can effectively reduce the accumulation of internal temperature stress, thereby delaying the formation of low-temperature cracks and improving low-temperature performance. Stress accumulation caused by temperature changes is an important factor causing low-temperature cracks, so it is very important to study the low-temperature creep characteristics of asphalt mixtures.

[0003] At present, the research on low-temperature creep characteristics of asphalt pavement mainly adopts methods such as low-temperature bending test, indirect tensile test, freeze-thaw cycle test, digital image correlation technology (DIC) and acoustic emission technology. However, these methods often take a long time in the specimen preparation and testing process, resulting in a complicated overall test cycle. In addition, most tests use a constant load, resulting in a stress state that does not match the actual road conditions. Therefore, the final evaluation results have the problem of unreasonable and inaccurate evaluation.

[0004] Therefore, there is an urgent need for a method and device for determining the low-temperature creep characteristics of asphalt mixtures. Summary of the invention

[0005] The present application provides a method and device for determining the low-temperature creep characteristics of asphalt mixtures, which solves the problem that the existing tests use a constant load and the final evaluation results are unreasonable and inaccurate.

[0006] In the first aspect of the present application, a method for determining the low-temperature creep characteristics of an asphalt mixture is provided, the method comprising: obtaining a target asphalt mixture test material, and cutting the target asphalt mixture test material according to a preset size; obtaining a standard small beam test piece after cutting, and performing a small beam bending failure test on the standard small beam test piece at a preset temperature; according to the small beam bending failure test, obtaining a maximum load corresponding to the standard small beam test piece; according to the maximum load, performing a step-by-step creep load test on the standard small beam test piece at a preset temperature, and calculating a first creep compliance corresponding to the standard small beam test piece; using a low-temperature creep characteristic evaluation model, performing a step-by-step creep load fitting test on the standard small beam test piece at a preset temperature, and calculating a second creep compliance corresponding to the standard small beam test piece; verifying the consistency of the first creep compliance through the second creep compliance, and obtaining a verification result; according to the verification result, and in combination with the dissipated energy ratio index, calculating the low-temperature creep performance of the target asphalt mixture test material at a preset temperature, and using the low-temperature creep performance as the evaluation result of the low-temperature creep characteristic test.

[0007] Optionally, a standard small beam test piece after cutting is obtained, and a small beam bending failure test is performed on the standard small beam test piece at a preset temperature, specifically including: obtaining multiple preset temperatures, the multiple preset temperatures include a first preset temperature, a second preset temperature, a third preset temperature and a fourth preset temperature, the first preset temperature, the second preset temperature, the third preset temperature and the fourth preset temperature are gradually increased according to a preset temperature gradient; and the standard small beam test piece is subjected to a small beam bending failure test at the first preset temperature, the second preset temperature, the third preset temperature and the fourth preset temperature, respectively.

[0008] Optionally, based on the maximum load, a gradually increasing creep load test is performed on the standard small beam test piece at a preset temperature, specifically including: obtaining a first target load increasing gradient corresponding to a first preset temperature in a preset gradient database, the preset gradient database being used to store the correspondence between the first preset temperature and the first target load increasing gradient; taking the maximum load as the initial load, and increasing the initial load step by step with the first target load increasing gradient as an increment until a first preset change condition is met, the first preset change condition being that the first creep compliance changes with changes in load.

[0009] Optionally, when the preset temperature is the first preset temperature and / or the second preset temperature, after taking the maximum load as the initial load and increasing the initial load step by step with the first target load increasing gradient as an increment until the first preset change condition is met, the method also includes: obtaining the second target load increasing gradient corresponding to the first preset temperature in the preset gradient database, the second target load increasing gradient being less than the first target load increasing gradient; increasing the initial load step by step with the second target load increasing gradient as an increment until the second preset change condition is met, the second preset change condition being that the trend of the first creep compliance changing with the load change meets the preset stability condition.

[0010] Optionally, calculating the first creep compliance corresponding to the standard beam test piece specifically includes: calculating the first creep compliance according to the following formula: ; in, is the deformation over time during the creep load test. The first creep compliance of the variation, is the creep bending tensile stress of the standard small beam test piece, is the load received by the standard beam test piece during the incremental creep load test, is the actual material strain response calculated by the step-by-step creep load test, is the span of the standard beam test piece, is the width of the cross section of the standard beam test piece, is the height of the cross section of the standard beam test piece, is the deformation over time during the creep load test. Varying mid-span deflection.

[0011] Optionally, calculating the second creep compliance corresponding to the standard beam test piece specifically includes: calculating the second creep compliance according to the following formula: ; in, is the deformation over time during the creep load test. Variation of the second creep compliance, is the instantaneous elastic parameter, To stabilize the elastic parameters, is the instantaneous viscous resistance parameter, To stabilize the viscous resistance parameters, Delay time during the incremental creep load test.

[0012] Optionally, based on the verification result and in combination with the dissipated energy ratio index, the low-temperature creep performance of the target asphalt mixed test material at a preset temperature is calculated, specifically including: obtaining a preset evaluation condition, the preset evaluation condition is to keep the first creep compliance and the second creep compliance in a linear elastic state; under the preset evaluation condition, the low-temperature creep performance is calculated according to the following formula: ; in, represents the dissipated energy ratio index, and is the dissipated energy corresponding to the target asphalt mixed test material, is the storage energy corresponding to the target asphalt mix test material.

[0013] In a second aspect of the present application, a device for measuring low-temperature creep characteristics of asphalt mixture is provided, the device comprising an acquisition module and a processing module, wherein: The acquisition module is used to obtain the target asphalt mixed test material and cut the target asphalt mixed test material according to the preset size; obtain the standard small beam test piece after cutting, and perform a small beam bending failure test on the standard small beam test piece at a preset temperature; according to the small beam bending failure test, obtain the maximum load corresponding to the standard small beam test piece.

[0014] A processing module is used to obtain the maximum load corresponding to the standard small beam test piece according to the small beam bending failure test; based on the maximum load, perform a step-by-step creep load test on the standard small beam test piece at a preset temperature, and calculate the first creep compliance corresponding to the standard small beam test piece; through a low-temperature creep property evaluation model, perform a step-by-step creep load fitting test on the standard small beam test piece at a preset temperature, and calculate the second creep compliance corresponding to the standard small beam test piece; verify the consistency of the first creep compliance through the second creep compliance, and obtain the verification result; based on the verification result and in combination with the dissipated energy ratio index, calculate the low-temperature creep performance of the target asphalt mixed test material at a preset temperature, and use the low-temperature creep performance as the evaluation result of the low-temperature creep property test.

[0015] In the third aspect of the present application, an electronic device is provided, including a processor, a memory, a user interface and a network interface, the memory is used to store instructions, the user interface and the network interface are used to communicate with other devices, and the processor is used to execute the instructions stored in the memory so that the electronic device executes any one of the methods described above.

[0016] In a fourth aspect of the present application, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores a computer program, and the computer program is executed by a processor to perform any of the above methods.

[0017] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages: 1. Cut the target asphalt mixture test material according to the preset size; obtain the standard small beam test piece after cutting, and perform a small beam bending failure test on the standard small beam test piece at the preset temperature to obtain the maximum load corresponding to the standard small beam test piece; according to the maximum load, perform a gradually increasing creep load test on the standard small beam test piece at the preset temperature, and calculate the first creep compliance corresponding to the standard small beam test piece; calculate the second creep compliance corresponding to the standard small beam test piece through the low-temperature creep characteristic evaluation model, perform consistency verification, and obtain the verification result; according to the verification result, and in combination with the dissipated energy ratio index, calculate the low-temperature creep performance of the target asphalt mixture test material at the preset temperature, so as to quickly and accurately evaluate the creep characteristics of the asphalt mixture at different load levels through the small beam bending creep test with step-by-step loading, which solves the problem that the existing test adopts a constant load and the final evaluation result has unreasonable and inaccurate evaluation.

[0018] 2. By setting multiple preset temperatures and conducting beam bending failure tests on standard beam test pieces at different preset temperatures, the influence of temperature on the brittleness, elasticity and creep behavior of asphalt mixtures is revealed, thereby more comprehensively and accurately evaluating the low-temperature performance of asphalt mixtures and providing data support for material selection and optimization.

[0019] 3. A low-temperature creep property evaluation model is constructed based on linear viscoelastic mechanics, and the low-temperature creep performance of the target asphalt mixture test material at a preset temperature is calculated in combination with the dissipated energy ratio index. Thus, by studying the dissipated energy ratio, the low-temperature creep characteristics of the asphalt mixture can be effectively evaluated. By analyzing the creep compliance and the dissipated energy ratio, the low-temperature creep performance of different types of asphalt mixtures at different temperatures and under the same loading conditions can be deeply evaluated. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic flow chart of a method for determining low-temperature creep characteristics of asphalt mixture provided in an embodiment of the present application; Figure 2 is a graph showing creep compliance changing with time provided in an embodiment of the present application; Figure 3 A histogram of the dissipated energy ratio of an asphalt mixed test material provided in the embodiment of the present application; Figure 4 It is a schematic diagram of a module of a low-temperature creep property measuring device for asphalt mixture provided in an embodiment of the present application; Figure 5 It is a structural schematic diagram of an electronic device provided in an embodiment of the present application.

[0021] Explanation of the reference numerals: 41, acquisition module; 42, processing module; 501, processor; 502, communication bus; 503, user interface; 504, network interface; 505, memory. DETAILED DESCRIPTION

[0022] In order to enable technicians in this field to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below in conjunction with the drawings in the embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this application, not all of the embodiments.

[0023] The terms used in the following embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to be used as limitations to the present application. As used in the specification of the present application, the singular expressions "one", "a kind of", "said", "above", "the" and "this" are intended to also include plural expressions, unless there is a clear indication to the contrary in the context. It should also be understood that the term "and / or" used in the present application refers to and includes any or all possible combinations of one or more listed items.

[0024] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as suggesting or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features, and in the description of the embodiments of the present application, unless otherwise specified, "plurality" means two or more.

[0025] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0026] Please refer to Figure 1 , which shows a schematic flow chart of a method for determining low-temperature creep characteristics of asphalt mixture provided in an embodiment of the present application, and the flow chart mainly includes the following steps: S101 to S107.

[0027] Step S101, obtaining a target asphalt mixture test material, and cutting the target asphalt mixture test material according to a preset size.

[0028] Specifically, when the user conducts a low-temperature creep property test on an asphalt mixture, the asphalt mixture specimen, i.e., the target asphalt mixture test material, is first prepared, and the size and preparation method of the specimen are determined. During the preparation process, the temperature of the target asphalt mixture test material and the particle size distribution of the aggregate need to be strictly controlled to ensure the uniformity and stability of the mixture. The prepared target asphalt mixture test material is cut into the preset size to obtain a standard small beam test piece for the test. Among them, a shear compactor ASC (Asphalt Shear Box Compactor) is used for molding. The shear pressure and temperature in the molding process should be set according to the test specifications to simulate the compaction effect of the asphalt mixture under actual road conditions. The size of the rectangular target asphalt mixture test material after molding is 45cm×15cm×15cm; the target asphalt mixture test material is cut into standard small beam test pieces by precise cutting tools, including but not limited to: band saws, cutting machines, etc. The size of the standard small beam test piece is 25cm×3cm wide×3.5cm high. During the cutting process, the dimensional accuracy of the small beam test piece must be ensured to avoid inaccurate test results due to dimensional errors. After cutting, each standard small beam test piece should be visually inspected to ensure that there are no cracks, bubbles or other defects to avoid affecting the test results.

[0029] Step S102, obtaining the cut standard beam test piece, and performing a beam bending failure test on the standard beam test piece at a preset temperature.

[0030] Specifically, a suitable cut standard beam test piece is selected: the selected standard beam test piece is ensured to meet the experimental requirements through appearance inspection, size confirmation, uniformity inspection and weight confirmation, etc. The beam bending failure test is performed on the standard beam test piece at different preset temperatures.

[0031] In a possible embodiment, step S102 also includes: obtaining multiple preset temperatures, the multiple preset temperatures include a first preset temperature, a second preset temperature, a third preset temperature and a fourth preset temperature, the first preset temperature, the second preset temperature, the third preset temperature and the fourth preset temperature are gradually increased according to a preset temperature gradient; performing a beam bending failure test on the standard beam test piece at the first preset temperature, the second preset temperature, the third preset temperature and the fourth preset temperature, respectively.

[0032] Specifically, the standard beam test piece is subjected to beam bending failure tests at different preset temperatures. In the embodiment of the present application, four different temperatures are set as preset temperatures for beam bending failure tests, namely, a first preset temperature, a second preset temperature, a third preset temperature, and a fourth preset temperature, wherein the first preset temperature is -30°C, the second preset temperature is -20°C, the third preset temperature is -10°C, and the fourth preset temperature is 0°C. At each temperature, the standard beam test piece needs to be kept warm for 4 hours before being placed in the instrument for beam bending failure tests.

[0033] Step S103, obtaining the maximum load corresponding to the standard small beam test piece according to the small beam bending failure test.

[0034] Specifically, according to the different preset temperatures set in step S102, the beam bending failure test is performed at four different temperatures, and the maximum load of the standard beam test piece at each preset temperature is recorded. The process is as follows: the standard beam test piece is placed on the support frame of the bending test machine to ensure that the placement of the standard beam test piece meets the requirements of the bending failure test. The distance of the support points and the loading method should be set strictly in accordance with the test specifications. During the test, the load is gradually applied to the midpoint of the standard beam test piece, and the load is continuously increased until the standard beam test piece is bent and damaged, and the load sensor and displacement sensor are used to monitor the load change in real time, and the load value displayed on the sensor when the standard beam test piece is bent and damaged is used as its maximum load value.

[0035] Step S104, performing a gradually increasing creep load test on the standard small beam test piece according to the maximum load and the preset temperature, and calculating a first creep compliance corresponding to the standard small beam test piece.

[0036] Specifically, according to the maximum load at each preset temperature, the creep load test of the standard small beam test piece is continuously performed at the corresponding temperature in a stepwise increasing manner, and the first creep compliance corresponding to the standard small beam test piece is calculated.

[0037] In a possible implementation, step S104 also includes: obtaining a first target load incremental gradient corresponding to a first preset temperature in a preset gradient database, the preset gradient database being used to store the correspondence between the first preset temperature and the first target load incremental gradient; taking the maximum load as the initial load, and increasing the initial load step by step with the first target load incremental gradient as an increment until a first preset change condition is met, the first preset change condition being that the first creep compliance changes with changes in the load.

[0038] Specifically, for the gradually increasing creep load fitting test at different preset temperatures, different increasing rules need to be set. At this time, a preset gradient database can be pre-constructed, which is used to store the correspondence between all preset temperatures and all load increasing gradients. For example, for the first preset temperature, that is, when the incremental creep load fitting test is carried out in an environment of -30°C, the first target load increasing gradient is a 20% increment. The maximum load obtained in the environment of -30°C is used as the initial load, and 20% of the maximum load at this temperature (i.e., 20%P) is used as the first-level creep load for step-by-step increase until the first preset change condition is met, that is, the first creep compliance changes with the load change, and in order to ensure that the specimen can enter the stable period and maintain it for a period of time, the duration of all tests is set to 1 hour. For the second preset temperature, that is, when the incremental creep load fitting test is performed in an environment of -20°C, the maximum load obtained in the environment of -20°C is used as the initial load, and 20% of the maximum load at this temperature (i.e., 20%P) is used as the first-level creep load for step-by-step increase until the first preset change condition is met. For the third preset temperature, that is, when the incremental creep load fitting test is performed in an environment of -10°C, the maximum load obtained in the environment of -10°C is used as the initial load, and 10% of the maximum load at this temperature (i.e., 10%P) is used as the first-level creep load for step-by-step increase until the first preset change condition is met. For the fourth preset temperature, that is, when the incremental creep load fitting test is performed in an environment of 0°C, the maximum load obtained in the environment of 0°C is used as the initial load, and 10% of the maximum load at this temperature (i.e., 10%P) is used as the first-level creep load for step-by-step increase until the first preset change condition is met.

[0039] In a possible embodiment, when the preset temperature is the first preset temperature and / or the second preset temperature, step S104 also includes: obtaining a second target load increasing gradient corresponding to the first preset temperature in a preset gradient database, the second target load increasing gradient being less than the first target load increasing gradient; increasing the initial load step by step with the second target load increasing gradient as an increment until a second preset change condition is met, the second preset change condition being that the trend of the first creep compliance changing with the load change meets a preset stability condition.

[0040] Specifically, at -20°C and -30°C, when the first creep compliance changes with the load, a load is added between this load and the previous load by 10% increments, and the 10% increment is the second target load increment gradient until the second preset change condition is met. The second preset change condition is that the trend of the first creep compliance changing with the load changes meets the preset stability condition, that is, the change amplitude of the first creep compliance is no longer significant, and reaches an equilibrium value or a constant value. In addition, in order to ensure the accuracy of the experiment, no less than 3 standard beam test pieces are tested in parallel under the same preset temperature test conditions.

[0041] After completing the step-by-step creep load test under each preset temperature condition, the first creep compliance is calculated according to the following formula: ; in, is the deformation over time during the creep load test. The first creep compliance of the variation, is the creep bending tensile stress of the standard small beam test piece, is the load received by the standard beam test piece during the incremental creep load test, is the actual material strain response calculated by the step-by-step creep load test, is the span of the standard beam test piece, is the width of the cross section of the standard beam test piece, is the height of the cross section of the standard beam test piece, is the deformation over time during the creep load test. Varying mid-span deflection.

[0042] Step S105, using the low-temperature creep characteristic evaluation model, a gradually increasing creep load fitting test is performed on the standard small beam test piece at a preset temperature, and a second creep compliance corresponding to the standard small beam test piece is calculated.

[0043] Specifically, a low-temperature creep characteristic evaluation model is constructed, and a gradually increasing creep load fitting test is performed on a standard small beam test piece at -30°C, -10°C, 0°C and 20°C. The gradually increasing creep load fitting test is a fitting simulation experiment of the incremental creep load of the standard small beam test piece through the low-temperature creep characteristic evaluation model, so as to calculate the second creep compliance and verify the determination result in step S104. The second creep compliance is calculated according to the following formula: ; in, is the deformation over time during the creep load test. Variation of the second creep compliance, is the instantaneous elastic parameter, To stabilize the elastic parameters, is the instantaneous viscous resistance parameter, To stabilize the viscous resistance parameters, is the delay time during the creep load test. The derivation process of this formula is as follows: ,and , so we can eliminate the numerator and denominator , we can get the above calculation formula, where, The material strain response derived from the low-temperature creep property evaluation model through fitting experiments.

[0044] Please refer to Figure 2, which shows a graph of creep compliance over time provided by an embodiment of the present application. It can be seen from the figure that under 0°C conditions, the creep compliance curve of 20%P has deviated significantly from 10%P, indicating that when the creep load increases from 10%P to 20%P, the viscoelastic properties of the target asphalt mixture test material change, and the target asphalt mixture test material enters a non-linear viscoelastic state from a linear viscoelastic state. Under -10°C conditions, when the creep load level is 10%~20%P, the creep compliance first increases with time and then tends to a constant value. The creep compliance curves of the target asphalt mixture test material under different loads overlap, indicating that within this load range, the three types of target asphalt mixture test materials are in a linear viscoelastic state, and the creep compliance does not change with the increase in load. When the creep load level increases to 30%P, the creep compliance of the target asphalt mixture test material specimen changes, and at this time the target asphalt mixture test material specimen is no longer in a linear viscoelastic state. Under -20℃, when the creep load level is 10%~50%P, the overlap of the creep compliance curve does not change, and the target asphalt mixed test material is in a linear viscoelastic state. When the creep load increases to 60%P, the creep compliance of the target asphalt mixed test material specimen changes, and the two target asphalt mixed test materials are no longer in a linear viscoelastic state. Under -30℃, the overlap of the creep compliance curve of the target asphalt mixed test material specimen at 10%~60%P does not change, and the target asphalt mixed test material is in a linear viscoelastic state. When the creep load level increases to 70%P, the creep compliance of the target asphalt mixed test material specimen changes, and the target asphalt mixed test material is no longer in a linear viscoelastic state. When the creep compliance of the target asphalt mixed test material changes with the change of load, it indicates that the material is no longer in a linear viscoelastic state.

[0045] The viscoelastic range of the target asphalt mixture test material is analyzed by creep compliance. In order to verify the above conclusion, the creep compliance of the target asphalt mixture test material at 10%P under various preset temperature conditions is fitted using the low-temperature creep property evaluation model. The fitting results of the creep compliance parameters are shown in Table 1.

[0046] [Table 1]

[0047] According to Table 1, when the creep load level is 10%P, under various temperature conditions, the creep compliance of the three asphalt mixtures is fitted by the low-temperature creep property evaluation model, and the creep compliance is used to analyze the linear viscoelastic range of the asphalt mixture to obtain the viscoelastic parameter results. 2 All greater than 0.99, R 2 is a statistic used to measure the goodness of fit of the low-temperature creep property evaluation model. 2It indicates the degree to which the independent variable explains the variation of the dependent variable, and its value range is between 0 and 1. 2 Greater than 0.99 means that, under all temperature conditions considered, the creep compliance data of the three asphalt mixtures can almost be well explained by the low-temperature creep property evaluation model. It also shows that these mixtures exhibit linear viscoelastic characteristics in various temperature ranges, which is consistent with the analysis conclusions. Therefore, the low-temperature creep property evaluation model in this application is effective.

[0048] Step S106: verify the consistency of the first creep compliance by using the second creep compliance, and obtain a verification result.

[0049] Specifically, first, the second creep compliance calculated in step S105 is compared with the first creep compliance obtained in step S104. If the difference between the two is within the preset error range, it is considered that the consistency verification is passed, indicating that the test results have good correspondence and reliability; if the difference between the two exceeds the error range, it is necessary to analyze the cause of the error, which includes but is not limited to errors caused by the test method, load increment process, inconsistent temperature control, etc., and adjust the test process accordingly. Finally, based on the results of the consistency verification, the effectiveness of the low-temperature creep characteristic evaluation model is judged to provide a basis for subsequent material performance evaluation.

[0050] Step S107, based on the verification result and in combination with the dissipated energy ratio index, calculate the low-temperature creep performance of the target asphalt mixture test material at a preset temperature, and use the low-temperature creep performance as the evaluation result of the low-temperature creep characteristic test.

[0051] Specifically, asphalt mixture will dissipate energy during the creep process. By studying the dissipated energy ratio, the low-temperature creep characteristics of asphalt mixture can be further evaluated. At this time, by obtaining the preset evaluation conditions, the preset evaluation conditions are to keep the first creep compliance and the second creep compliance in a linear elastic state. The dissipated energy ratio is a function of time t. The time t is 2000s when the creep compliance is in a stable linear change stage. The fitting results of each parameter of the creep compliance in step S105 are respectively brought into the following calculations: ; in, represents the dissipated energy ratio index, and is the dissipated energy corresponding to the target asphalt mixed test material, is the storage energy corresponding to the target asphalt mix test material.

[0052] Please refer to Figure 3 , which shows a dissipated energy ratio bar graph of an asphalt mixed test material provided in an embodiment of the present application. Figure 3It can be seen that: as the temperature decreases, the dissipated energy ratio of the target asphalt mixture test material decreases, indicating that the creep deformation continues to decrease during the cooling process, which accelerates the rate of energy accumulation of the internal temperature stress of the target asphalt mixture test material, resulting in the asphalt mixture being more susceptible to damage and the poorer low-temperature performance. Therefore, through the test method in the embodiment of the present application, it can be concluded that the low-temperature creep properties of the target asphalt mixture test material gradually deteriorate as the temperature decreases, mainly because the internal viscoelastic components undergo transformation during the cooling process, and the amount of transformation decreases as the temperature decreases. Using creep compliance and dissipated energy ratio to comprehensively evaluate the creep properties of different types of asphalt mixtures at low temperatures can effectively quantify their deformation capacity and energy dissipation characteristics.

[0053] The present application adopts the above-mentioned method to cut the target asphalt mixture test material according to the preset size; obtain the standard small beam test piece after cutting, and perform a small beam bending failure test on the standard small beam test piece at a preset temperature to obtain the maximum load corresponding to the standard small beam test piece; according to the maximum load, perform a step-by-step creep load test on the standard small beam test piece at a preset temperature, and calculate the first creep compliance corresponding to the standard small beam test piece; calculate the second creep compliance corresponding to the standard small beam test piece through a low-temperature creep characteristic evaluation model, perform consistency verification, and obtain the verification result; according to the verification result, and in combination with the dissipated energy ratio index, calculate the low-temperature creep performance of the target asphalt mixture test material at a preset temperature, so as to quickly and accurately evaluate the creep characteristics of the asphalt mixture at different load levels through the small beam bending creep test with step-by-step loading, thereby solving the problem that the existing test adopts a constant load and the final evaluation result has unreasonable and inaccurate evaluation.

[0054] Please refer to Figure 4 , which shows a schematic diagram of a module of a device for measuring low-temperature creep characteristics of asphalt mixture provided in an embodiment of the present application, the device includes an acquisition module 41 and a processing module 42, wherein: The acquisition module 41 is used to obtain the target asphalt mixed test material and cut the target asphalt mixed test material according to the preset size; obtain the standard small beam test piece after cutting, and perform a small beam bending failure test on the standard small beam test piece according to the preset temperature; according to the small beam bending failure test, obtain the maximum load corresponding to the standard small beam test piece.

[0055] The processing module 42 is used to obtain the maximum load corresponding to the standard small beam test piece according to the small beam bending failure test; based on the maximum load, perform a step-by-step creep load test on the standard small beam test piece at a preset temperature, and calculate the first creep compliance corresponding to the standard small beam test piece; through a low-temperature creep characteristic evaluation model, perform a step-by-step creep load fitting test on the standard small beam test piece at a preset temperature, and calculate the second creep compliance corresponding to the standard small beam test piece; verify the consistency of the first creep compliance through the second creep compliance, and obtain the verification result; based on the verification result and in combination with the dissipated energy ratio index, calculate the low-temperature creep performance of the target asphalt mixed test material at a preset temperature, and use the low-temperature creep performance as the evaluation result of the low-temperature creep characteristic test.

[0056] In a possible embodiment, the acquisition module 41 is used to obtain the standard small beam test piece after cutting, and perform a small beam bending failure test on the standard small beam test piece according to a preset temperature, specifically including: obtaining multiple preset temperatures, the multiple preset temperatures include a first preset temperature, a second preset temperature, a third preset temperature and a fourth preset temperature, the first preset temperature, the second preset temperature, the third preset temperature and the fourth preset temperature are gradually increased according to a preset temperature gradient; performing a small beam bending failure test on the standard small beam test piece at the first preset temperature, the second preset temperature, the third preset temperature and the fourth preset temperature respectively.

[0057] In one possible embodiment, the processing module 42 is used to perform a gradually increasing creep load test on the standard small beam test piece according to the maximum load and the preset temperature, specifically including: obtaining a first target load increasing gradient corresponding to the first preset temperature in a preset gradient database, the preset gradient database is used to store the correspondence between the first preset temperature and the first target load increasing gradient; taking the maximum load as the initial load, and increasing the initial load step by step with the first target load increasing gradient as an increment until the first preset change condition is met, and the first preset change condition is that the first creep compliance changes with the load change.

[0058] In a possible embodiment, when the preset temperature is the first preset temperature and / or the second preset temperature, the processing module 42 is used to take the maximum load as the initial load and increase the initial load step by step with the first target load increasing gradient as an increment until the first preset change condition is met, and the method also includes: obtaining the second target load increasing gradient corresponding to the first preset temperature in the preset gradient database, the second target load increasing gradient is less than the first target load increasing gradient; increasing the initial load step by step with the second target load increasing gradient as an increment until the second preset change condition is met, and the second preset change condition is that the trend of the first creep compliance changing with the load change satisfies the preset stability condition.

[0059] In a possible implementation, the processing module 42 is used to calculate the first creep compliance corresponding to the standard beam test piece, specifically including: calculating the first creep compliance according to the following formula: ; in, is the deformation over time during the creep load test. The first creep compliance of the variation, is the creep bending tensile stress of the standard small beam test piece, is the load received by the standard beam test piece during the incremental creep load test, is the actual material strain response calculated by the step-by-step creep load test, is the span of the standard beam test piece, is the width of the cross section of the standard beam test piece, is the height of the cross section of the standard beam test piece, is the deformation over time during the creep load test. Varying mid-span deflection.

[0060] In a possible implementation, the processing module 42 is used to calculate the second creep compliance corresponding to the standard beam test piece, specifically including: calculating the second creep compliance according to the following formula: ; in, is the deformation over time during the creep load test. Variation of the second creep compliance, is the instantaneous elastic parameter, To stabilize the elastic parameters, is the instantaneous viscous resistance parameter, To stabilize the viscous resistance parameters, Delay time during the incremental creep load test.

[0061] In a possible implementation, the processing module 42 is used to calculate the low-temperature creep performance of the target asphalt mixed test material at a preset temperature based on the verification result and in combination with the dissipated energy ratio index, specifically including: obtaining a preset evaluation condition, the preset evaluation condition is to keep the first creep compliance and the second creep compliance in a linear elastic state; under the preset evaluation condition, calculating the low-temperature creep performance according to the following formula: ; in, represents the dissipated energy ratio index, and is the dissipated energy corresponding to the target asphalt mixed test material, is the storage energy corresponding to the target asphalt mix test material.

[0062] It should be noted that: when the device provided in the above embodiment realizes its function, only the division of the above functional modules is used as an example. In actual application, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. In addition, the device and method embodiments provided in the above embodiment belong to the same concept, and the specific implementation process is detailed in the method embodiment, which will not be repeated here.

[0063] The present application also provides an electronic device. Figure 5 , Figure 5 1 is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. The electronic device may include: at least one processor 501, at least one communication bus 502, a user interface 503, at least one network interface 504, and a memory 505.

[0064] The communication bus 502 is used to realize the connection and communication between these components.

[0065] The user interface 503 may include a display screen (Display) and a camera (Camera). Optionally, the user interface 503 may also include a standard wired interface and a wireless interface.

[0066] The network interface 504 may optionally include a standard wired interface or a wireless interface (such as a WI-FI interface).

[0067] Among them, the processor 501 may include one or more processing cores. The processor 501 uses various interfaces and lines to connect various parts in the entire server, and executes various functions of the server and processes data by running or executing instructions, programs, code sets or instruction sets stored in the memory 505, and calling data stored in the memory 505. Optionally, the processor 501 can be implemented in at least one hardware form of digital signal processing (Digital Signal Processing, DSP), field programmable gate array (Field-Programmable Gate Array, FPGA), and programmable logic array (Programmable Logic Array, PLA). The processor 501 can integrate one or a combination of a central processing unit (Central Processing Unit, CPU), a graphics processing unit (Graphics Processing Unit, GPU) and a modem. Among them, the CPU mainly processes the operating system, user interface and application programs; the GPU is responsible for rendering and drawing the content to be displayed on the display screen; the modem is used to process wireless communications. It can be understood that the above-mentioned modem may not be integrated into the processor 501, and it can be implemented separately through a chip.

[0068] Among them, the memory 505 may include a random access memory (Random Access Memory, RAM) and may also include a read-only memory (Read-Only Memory). Optionally, the memory 505 includes a non-transitory computer-readable storage medium. The memory 505 can be used to store instructions, programs, codes, code sets or instruction sets. The memory 505 may include a program storage area and a data storage area, wherein the program storage area may store instructions for implementing an operating system, instructions for at least one function (such as a touch function, a sound playback function, an image playback function, etc.), instructions for implementing the above-mentioned various method embodiments, etc.; the data storage area may store data involved in the above-mentioned various method embodiments, etc. The memory 505 may also be optionally at least one storage device located away from the aforementioned processor 501. Refer to Figure 3 The memory 505 as a computer storage medium may include an operating system, a network communication module, a user interface module, and an application program for determining the low-temperature creep characteristics of asphalt mixture.

[0069] exist Figure 5In the electronic device shown, the user interface 503 is mainly used to provide an input interface for the user and obtain the data input by the user; and the processor 501 can be used to call the low-temperature creep property determination application of asphalt mixture stored in the memory 505. When executed by one or more processors 501, the electronic device executes one or more of the methods described in the above embodiments. It should be noted that for the aforementioned method embodiments, for the sake of simple description, they are all expressed as a series of action combinations, but those skilled in the art should know that the present application is not limited by the described order of actions, because according to the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required for the present application.

[0070] The present application also provides a computer-readable storage medium, which stores instructions. When executed by one or more processors, the electronic device executes one or more of the methods described in the above embodiments.

[0071] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0072] In the several embodiments provided in this application, it should be understood that the disclosed devices can be implemented in other ways. For example, the device embodiments described above are only schematic, such as the division of units, which is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some service interfaces, and the indirect coupling or communication connection of devices or units can be electrical or other forms.

[0073] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0074] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0075] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable memory. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, which is stored in a memory and includes several instructions for a computer device (which can be a personal computer, server or network device, etc.) to execute all or part of the steps of the various embodiments of the present application. The aforementioned memory includes: various media that can store program codes, such as USB flash drives, mobile hard drives, magnetic disks or optical disks.

[0076] The above are only exemplary embodiments disclosed in this application, and the scope of the disclosure of this application cannot be limited by this. That is, any equivalent changes and modifications made according to the teachings disclosed in this application are still within the scope of the disclosure of this application. After considering the disclosure of the specification and the truth of practice, those skilled in the art will easily think of other implementation schemes disclosed in this application.

[0077] This application is intended to cover any modifications, uses or adaptive changes disclosed in this application, which follow the general principles disclosed in this application and include common knowledge or customary technical means in the technical field not recorded in this application.

Claims

1. A method for determining the low temperature creep characteristics of asphalt mixture, characterized in that: The method comprises: Obtaining a target asphalt mixed test material, and cutting the target asphalt mixed test material according to a preset size; Obtaining the cut standard beam test piece, and performing a beam bending failure test on the standard beam test piece at a preset temperature; According to the beam bending failure test, obtaining the maximum load corresponding to the standard beam test piece; According to the maximum load, the standard small beam test piece is subjected to a gradually increasing creep load test at the preset temperature, and a first creep compliance corresponding to the standard small beam test piece is calculated; Through the low-temperature creep characteristic evaluation model, a gradually increasing creep load fitting test is performed on the standard small beam test piece according to the preset temperature, and a second creep compliance corresponding to the standard small beam test piece is calculated; Performing consistency verification on the first creep compliance by using the second creep compliance, and obtaining a verification result; According to the verification result, the low-temperature creep performance of the target asphalt mixture test material at the preset temperature is calculated in combination with the dissipated energy ratio index, and the low-temperature creep performance is used as the evaluation result of the low-temperature creep characteristic test.

2. The method according to claim 1, characterized in that: The step of obtaining the cut standard beam test piece and performing a beam bending failure test on the standard beam test piece at a preset temperature specifically includes: Acquire a plurality of preset temperatures, the plurality of preset temperatures comprising a first preset temperature, a second preset temperature, a third preset temperature and a fourth preset temperature, the first preset temperature, the second preset temperature, the third preset temperature and the fourth preset temperature increasing step by step according to a preset temperature gradient; The beam bending failure test is performed on the standard beam test piece at the first preset temperature, the second preset temperature, the third preset temperature and the fourth preset temperature respectively.

3. The method according to claim 2, characterized in that The stepwise increasing creep load test is performed on the standard beam test piece according to the maximum load and the preset temperature, specifically comprising: Acquire a first target load incremental gradient corresponding to the first preset temperature in a preset gradient database, wherein the preset gradient database is used to store a corresponding relationship between the first preset temperature and the first target load incremental gradient; The maximum load is used as the initial load, and the initial load is gradually increased with the first target load incremental gradient as an increment until a first preset change condition is met, wherein the first preset change condition is that the first creep compliance changes with the load change.

4. The method according to claim 3, characterized in that: When the preset temperature is the first preset temperature and / or the second preset temperature, after taking the maximum load as the initial load and increasing the initial load step by step with the first target load incremental gradient as an increment until the first preset change condition is met, the method further includes: Acquire a second target load increasing gradient corresponding to the first preset temperature in a preset gradient database, wherein the second target load increasing gradient is smaller than the first target load increasing gradient; The initial load is increased step by step with the second target load increasing gradient as an increment until a second preset change condition is met, wherein the second preset change condition is that a trend of the first creep compliance changing with load changes meets a preset stability condition.

5. The method according to claim 1, characterized in that The calculating the first creep compliance corresponding to the standard beam test piece specifically includes: The first creep compliance is calculated according to the following formula: ； in, is the change in the creep load over time during the creep load test. Variation of the first creep compliance, is the load received by the standard beam test piece during the incremental creep load test, is the creep bending tensile stress of the standard beam test piece, is the actual material strain response calculated by the step-by-step creep load test, is the span of the standard beam test piece, is the width of the cross-section of the standard beam test piece, is the height of the cross section of the standard beam test piece, is the change in the creep load over time during the creep load test. Varying mid-span deflection.

6. The method according to claim 4, characterized in that The calculating the second creep compliance corresponding to the standard beam test piece specifically includes: The second creep compliance is calculated according to the following formula: ； in, is the change in the creep load over time during the creep load test. Variation of the second creep compliance, is the instantaneous elastic parameter, To stabilize the elastic parameters, is the instantaneous viscous resistance parameter, To stabilize the viscous resistance parameters, It is the delay time during the incremental creep load test.

7. The method according to claim 6, characterized in that The step of calculating the low temperature creep performance of the target asphalt mixture test material at the preset temperature based on the verification result and in combination with the dissipated energy ratio index specifically includes: Acquiring a preset evaluation condition, wherein the preset evaluation condition is to keep the first creep compliance and the second creep compliance in a linear elastic state; Under the preset evaluation conditions, the low temperature creep performance is calculated according to the following formula: ； in, represents the dissipated energy ratio index, and is the dissipated energy corresponding to the target asphalt mixed test material, is the storage energy corresponding to the target asphalt mixed test material.

8. A device for measuring low temperature creep characteristics of asphalt mixture, characterized in that: The device comprises an acquisition module and a processing module, wherein: The acquisition module is used to acquire the target asphalt mixed test material, cut the target asphalt mixed test material according to a preset size; acquire the standard small beam test piece after cutting, and perform a small beam bending failure test on the standard small beam test piece according to a preset temperature; and acquire the maximum load corresponding to the standard small beam test piece according to the small beam bending failure test; The processing module is used to perform a gradually increasing creep load test on the standard beam test piece according to the maximum load and the preset temperature, and calculate the first creep compliance corresponding to the standard beam test piece; perform a gradually increasing creep load fitting test on the standard beam test piece according to the preset temperature through a low-temperature creep property evaluation model, and calculate the second creep compliance corresponding to the standard beam test piece; perform consistency verification on the first creep compliance through the second creep compliance, and obtain the verification result; calculate the low-temperature creep performance of the target asphalt mixed test material at the preset temperature according to the verification result and in combination with the dissipated energy ratio index, and use the low-temperature creep performance as the evaluation result of the low-temperature creep property test.

9. An electronic device, characterized in that: It includes a processor, a communication bus, a user interface, a network interface and a memory, wherein the memory is used to store instructions, the user interface and the network interface are used to communicate with other devices, and the processor is used to execute the instructions stored in the memory so that the electronic device executes the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores instructions, and when the instructions are executed, the method according to any one of claims 1 to 7 is performed.

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