System and method for testing repeated shrinkage fatigue of transition layer between asphalt pavement and base layer

Abstract

The invention discloses a system and a method for testing repeated shrinkage fatigue of a transition layer between an asphalt pavement and a base layer, and relates to the technical field of road detection, the system comprises a sample fixing device, a load applying device, a temperature control device, a displacement measuring device and a data acquisition and processing device; the sample fixing device comprises an upper clamp and a lower clamp, the upper clamp is used for fixing an asphalt layer, and the lower clamp is used for fixing a base layer; the load applying device comprises a loading head and a loading control system, the loading head is connected with the upper clamp, and repeated loads are applied through the loading control system; the temperature control device comprises a temperature box and a temperature controller; the temperature box is used for placing a sample and controlling the temperature change of the sample; the displacement measuring device comprises a displacement sensor and a data collector, the displacement sensor is used for measuring the deformation condition of the sample under the load effect, and the data collector is used for recording measured data; and the data acquisition and processing device comprises a computer and data processing software and is used for analyzing and processing test data.

Description

Technical Field

[0001] The invention relates to the technical field of road testing, and in particular to a system and method for testing repeated shrinkage fatigue of a transition layer between an asphalt pavement and a base layer. Background Art

[0002] In modern road construction, asphalt pavement is widely used in various types of traffic roads. The structure of asphalt pavement is complex, usually including a multi-layer structure such as a surface layer, an intermediate layer, a base layer and a subbase layer. In order to improve the overall performance of the pavement, a transition layer is often set between the asphalt pavement and the base layer to improve the interface bonding performance and enhance the durability of the pavement structure. However, during the use of asphalt pavement, affected by vehicle loads and changes in ambient temperature, the pavement and its layers will produce repeated stress and deformation, especially the transition layer will experience repeated shrinkage and fatigue. These effects will cause early damage to the pavement, such as cracks and rutting, affecting the service life of the road and driving safety. Therefore, studying the repeated shrinkage and fatigue performance of the transition layer has become an important topic to ensure the quality of the pavement. Summary of the invention

[0003] The purpose of the present invention is to overcome the above-mentioned deficiencies in the prior art and to provide a system and method for testing the repeated shrinkage fatigue of the transition layer between the asphalt pavement and the base layer, so as to more accurately evaluate the fatigue performance of the transition layer, guide practical engineering applications, and improve the durability and service life of the road.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] On one hand, the present invention provides a repeated shrinkage fatigue test system for a transition layer between an asphalt pavement and a base layer, comprising a sample fixing device, a load applying device, a temperature control device, a displacement measuring device, and a data acquisition and processing device;

[0006] The sample fixing device includes an upper clamp and a lower clamp, the upper clamp is used to fix the asphalt layer, and the lower clamp is used to fix the base layer;

[0007] The load applying device includes a loading head and a loading control system, the loading head is connected to the upper fixture, and repeated loads are applied through the loading control system;

[0008] The temperature control device includes a temperature box and a temperature controller. The temperature box is used to place the sample and control its temperature change;

[0009] The displacement measuring device includes a displacement sensor and a data collector. The displacement sensor is used to measure the deformation of the sample under load, and the data collector is used to record the measurement data.

[0010] The data acquisition and processing device includes a computer and data processing software, which are used to analyze and process the test data.

[0011] Another aspect of the present invention provides a method for testing the repeated shrinkage fatigue of a transition layer between an asphalt pavement and a base layer, which is implemented based on the above-mentioned system for testing the repeated shrinkage fatigue of a transition layer between an asphalt pavement and a base layer, and includes the following steps:

[0012] Specimen preparation: Select a standard specimen mold, mix the asphalt mixture according to standard specifications, and compact it in two layers in the mold. Set a layer of base material under the asphalt layer to form a transition layer structure;

[0013] Specimen fixing: Place the formed specimen on the fatigue test equipment and fix the specimen with a fixing device; ensure that the contact surface between the specimen and the equipment is flat to prevent the specimen from sliding during the test;

[0014] Loading condition setting: Set the loading frequency and loading amplitude of the fatigue test equipment. The loading amplitude is selected according to the actual working conditions. Set the number of test cycles. Generally, 100,000 cycles are selected.

[0015] Temperature control: During the test, the temperature of the environment around the test piece is kept constant by temperature control equipment; tests can be carried out under different temperature conditions as needed;

[0016] Data acquisition: During the loading process, the deformation data of the specimen is collected in real time through sensors, especially the deformation of the transition layer, and the maximum deformation and recovery deformation of each loading cycle are recorded;

[0017] Fatigue life analysis: The deformation data of the specimen at different cycle times are analyzed through data processing software. The fatigue life of the transition layer is determined based on the changing trend of the deformation. Combined with the stress-strain relationship, the fatigue resistance of the transition layer is analyzed to evaluate its application effect in actual roads.

[0018] Furthermore, in the specimen preparation, the specimen is prepared with a size of 300 mm×300 mm×50 mm.

[0019] Furthermore, after the specimens are prepared, a curing period is reserved: the non-modified asphalt mixture is placed for 2 to 3 days; the modified asphalt mixture is placed for 3 to 5 days, the high-viscosity modified asphalt mixture is placed for 5 to 10 days, and the high-polymer modified asphalt mixture is placed for 10 to 15 days.

[0020] Furthermore, fatigue life analysis specifically includes the following processes:

[0021] Data processing: The stress-strain data collected during the experiment are preprocessed to remove noise and abnormal data. Then, based on the collected stress and deformation data, the stress amplitude and strain amplitude in each loading cycle are calculated. Finally, the stress-strain data are cycle counted to count the number of cycles of the sample under different stress amplitudes.

[0022] Fatigue damage calculation: Miner linear cumulative damage theory is used to calculate the fatigue damage accumulation value of the specimen, and then the critical value of the fatigue damage accumulation value D is set (usually D = 1). When D reaches the critical value, the specimen is considered to have fatigue failure. Finally, the fatigue damage accumulation rate is calculated based on the stress amplitude and number of cycles of each loading cycle.

[0023] Fatigue life prediction: According to the SN curve (stress-life curve), the fatigue life of the sample under different stress amplitudes is determined, and then the fatigue performance parameters of the material are determined by fitting the SN curve based on the test data. Finally, the fatigue life of the sample in actual use is predicted based on the cumulative damage model and the SN curve.

[0024] Result analysis and evaluation: The fatigue life of different specimens is compared and analyzed to evaluate the effects of different materials and construction processes on fatigue performance. Then, based on the test results, suggestions are put forward to improve the transition layer materials and construction processes to increase the service life and performance of the road. Finally, the fatigue failure mode of the specimens is analyzed to explore the mechanism and influencing factors of fatigue failure.

[0025] Beneficial effects of the present invention:

[0026] High precision: Through precise specimen preparation and loading condition control, the fatigue performance of the transition layer can be truly reflected.

[0027] Controllability: By adjusting the loading frequency, amplitude and ambient temperature, fatigue effects under different working conditions can be simulated.

[0028] Comprehensive data: Through real-time data collection and analysis, detailed fatigue deformation data can be obtained, providing a basis for the optimal design of transition layer materials.

[0029] Wide application: It is suitable for testing different types of asphalt pavement structures and transition layer materials, and has a wide range of engineering application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the main process of the testing method in the present invention. DETAILED DESCRIPTION

[0031] The present invention is further described in detail below in conjunction with test examples and specific implementation methods. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0032] like Figure 1 As shown, in one aspect, this embodiment provides a repeated shrinkage fatigue test system for the transition layer between an asphalt pavement and a base layer, including a sample fixing device, a load applying device, a temperature control device, a displacement measuring device, and a data acquisition and processing device;

[0033] The sample fixing device includes an upper clamp and a lower clamp, the upper clamp is used to fix the asphalt layer, and the lower clamp is used to fix the base layer;

[0034] The load applying device includes a loading head and a loading control system, the loading head is connected to the upper fixture, and repeated loads are applied through the loading control system;

[0035] The temperature control device includes a temperature box and a temperature controller. The temperature box is used to place the sample and control its temperature change;

[0036] The displacement measuring device includes a displacement sensor and a data collector. The displacement sensor is used to measure the deformation of the sample under load, and the data collector is used to record the measurement data.

[0037] The data acquisition and processing device includes a computer and data processing software, which are used to analyze and process the test data.

[0038] On the other hand, the present embodiment provides a method for repeated shrinkage fatigue testing of a transition layer between an asphalt pavement and a base layer, which is implemented based on the above-mentioned repeated shrinkage fatigue testing system for a transition layer between an asphalt pavement and a base layer, and includes the following steps:

[0039] Specimen preparation: Select a standard specimen mold, mix the asphalt mixture according to standard specifications, and compact it in two layers in the mold. Set a layer of base material under the asphalt layer to form a transition layer structure;

[0040] Specimen fixing: Place the formed specimen on the fatigue test equipment and fix the specimen with a fixing device; ensure that the contact surface between the specimen and the equipment is flat to prevent the specimen from sliding during the test;

[0041] Loading condition setting: Set the loading frequency and loading amplitude of the fatigue test equipment. The loading amplitude is selected according to the actual working conditions. Set the number of test cycles. Generally, 100,000 cycles are selected.

[0042] Temperature control: During the test, the temperature of the environment around the test piece is kept constant by temperature control equipment; tests can be carried out under different temperature conditions as needed;

[0043] Data acquisition: During the loading process, the deformation data of the specimen is collected in real time through sensors, especially the deformation of the transition layer, and the maximum deformation and recovery deformation of each loading cycle are recorded;

[0044] Fatigue life analysis: The deformation data of the specimen at different cycle times are analyzed through data processing software. The fatigue life of the transition layer is determined based on the changing trend of the deformation. Combined with the stress-strain relationship, the fatigue resistance of the transition layer is analyzed to evaluate its application effect in actual roads.

[0045] The above embodiment is further optimized. In the test piece preparation, the test piece is prepared with a size of 300 mm×300 mm×50 mm.

[0046] The above embodiment is further optimized. After the specimen preparation is completed, a curing period is reserved. The non-modified asphalt mixture is placed for 2 days to 3 days; the modified asphalt mixture is placed for 3 days to 5 days, the high-viscosity modified asphalt mixture is placed for 5 days to 10 days, and the high-polymer modified asphalt mixture is placed for 10 days to 15 days.

[0047] Further optimizing the above embodiment, fatigue life analysis specifically includes the following process:

[0048] Data processing: The stress-strain data collected during the experiment are preprocessed to remove noise and abnormal data. Then, based on the collected stress and deformation data, the stress amplitude and strain amplitude in each loading cycle are calculated. Finally, the stress-strain data are cycle counted to count the number of cycles of the sample under different stress amplitudes.

[0049] Fatigue damage calculation: Miner linear cumulative damage theory is used to calculate the fatigue damage accumulation value of the specimen, and then the critical value of the fatigue damage accumulation value D is set (usually D = 1). When D reaches the critical value, the specimen is considered to have fatigue failure. Finally, the fatigue damage accumulation rate is calculated based on the stress amplitude and number of cycles of each loading cycle.

[0050] Fatigue life prediction: According to the SN curve (stress-life curve), the fatigue life of the sample under different stress amplitudes is determined, and then the fatigue performance parameters of the material are determined by fitting the SN curve based on the test data. Finally, the fatigue life of the sample in actual use is predicted based on the cumulative damage model and the SN curve.

[0051] Result analysis and evaluation: The fatigue life of different specimens is compared and analyzed to evaluate the effects of different materials and construction processes on fatigue performance. Then, based on the test results, suggestions are put forward to improve the transition layer materials and construction processes to increase the service life and performance of the road. Finally, the fatigue failure mode of the specimens is analyzed to explore the mechanism and influencing factors of fatigue failure.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A repeated shrinkage fatigue test system for the transition layer between an asphalt pavement and a base layer, characterized in that: It includes a sample fixing device, a load applying device, a temperature control device, a displacement measuring device and a data acquisition and processing device; The sample fixing device includes an upper clamp and a lower clamp, the upper clamp is used to fix the asphalt layer, and the lower clamp is used to fix the base layer; The load applying device includes a loading head and a loading control system, wherein the loading head is connected to the upper fixture and a repeated load is applied through the loading control system; The temperature control device includes a temperature box and a temperature controller. The temperature box is used to place the sample and control its temperature change; The displacement measuring device includes a displacement sensor and a data collector. The displacement sensor is used to measure the deformation of the sample under load, and the data collector is used to record the measurement data. The data acquisition and processing device includes a computer and data processing software, which are used to analyze and process the test data.

2. A method for testing the repeated shrinkage fatigue of a transition layer between an asphalt pavement and a base layer, implemented based on the system for testing the repeated shrinkage fatigue of a transition layer between an asphalt pavement and a base layer as claimed in claim 1, characterized in that: The steps include: Specimen preparation: Select a standard specimen mold, mix the asphalt mixture according to standard specifications, and compact it in two layers in the mold. Set a layer of base material under the asphalt layer to form a transition layer structure; Specimen fixing: Place the formed specimen on the fatigue test equipment and fix the specimen with a fixing device; ensure that the contact surface between the specimen and the equipment is flat to prevent the specimen from sliding during the test; Loading condition setting: Set the loading frequency and loading amplitude of the fatigue test equipment. The loading amplitude is selected according to the actual working conditions. Set the number of test cycles. Generally, 100,000 cycles are selected. Temperature control: During the test, the temperature of the environment around the test piece is kept constant by temperature control equipment; tests can be carried out under different temperature conditions as needed; Data acquisition: During the loading process, the deformation data of the specimen is collected in real time through sensors, especially the deformation of the transition layer, and the maximum deformation and recovery deformation of each loading cycle are recorded; Fatigue life analysis: The deformation data of the specimen at different cycle times are analyzed through data processing software. The fatigue life of the transition layer is determined based on the changing trend of the deformation. Combined with the stress-strain relationship, the fatigue resistance of the transition layer is analyzed to evaluate its application effect in actual roads.

3. The method for repeated shrinkage fatigue testing of a transition layer between an asphalt pavement and a base layer according to claim 2, characterized in that: In the specimen preparation, the specimen preparation size is 300mm×300mm×50mm.

4. The method for repeated shrinkage fatigue testing of a transition layer between an asphalt pavement and a base layer according to claim 2, characterized in that: After the specimen preparation is completed, a curing period is reserved: the non-modified asphalt mixture is placed for 2d to 3d; the modified asphalt mixture is placed for 3d to 5d, the high-viscosity modified asphalt mixture is placed for 5d to 10d, and the high-polymer modified asphalt mixture is placed for 10d to 15d.

5. The method for repeated shrinkage fatigue testing of a transition layer between an asphalt pavement and a base layer according to claim 2, characterized in that: Fatigue life analysis specifically includes the following processes: Data processing: The stress-strain data collected during the experiment are preprocessed to remove noise and abnormal data. Then, based on the collected stress and deformation data, the stress amplitude and strain amplitude in each loading cycle are calculated. Finally, the stress-strain data are cycle counted to count the number of cycles of the sample under different stress amplitudes. Fatigue damage calculation: Miner linear cumulative damage theory is used to calculate the fatigue damage accumulation value of the sample, and then the critical value of the fatigue damage accumulation value D is set (usually D=1). When D reaches the critical value, the sample is considered to have fatigue failure. Finally, the fatigue damage accumulation rate is calculated based on the stress amplitude and number of cycles of each loading cycle. Fatigue life prediction: According to the SN curve (stress-life curve), the fatigue life of the sample under different stress amplitudes is determined, and then the fatigue performance parameters of the material are determined by fitting the SN curve based on the test data. Finally, the fatigue life of the sample in actual use is predicted based on the cumulative damage model and the SN curve. Result analysis and evaluation: The fatigue life of different specimens is compared and analyzed to evaluate the effects of different materials and construction processes on fatigue performance. Then, based on the test results, suggestions are put forward to improve the transition layer materials and construction processes to increase the service life and performance of the road. Finally, the fatigue failure mode of the specimens is analyzed to explore the mechanism and influencing factors of fatigue failure.

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