Method for determining heating temperature of hot recycled old materials and heating temperature determination system

Abstract

The present invention provides a method for determining the heating temperature of hot recycled old materials and a heating temperature determination system. The method for determining the heating temperature of hot recycled old materials includes: placing more than one portion of asphalt old materials at different heating temperatures for a preset time; recovering the heated asphalt old materials to obtain old asphalt specimens at different heating temperatures; conducting multiple stress creep recovery tests on the old asphalt specimens at different heating temperatures, and analyzing the test results by the significant F-test method to obtain the upper limit of the heating design temperature of the asphalt old materials; preparing standard Marshall specimens using the heated asphalt old materials, and conducting high-temperature, low-temperature, and fatigue performance tests on the standard Marshall specimens to obtain the lower limit of the heating design temperature of the asphalt old materials; calculating the average value of the upper limit of the heating design temperature of the asphalt old materials and the lower limit of the heating design temperature of the asphalt old materials, and taking this average value as the heating temperature of the hot recycled old materials. The present invention can provide theoretical support for improving the effective utilization of old materials.

Description

Technical Field

[0001] The present invention relates to the technical field of recycling of asphalt mixtures, and particularly to a method for determining the heating temperature of hot recycled old materials and a heating temperature determination system. Background Art

[0002] The central plant hot recycling (CPHR) technology of waste asphalt pavement materials, as an environmentally friendly and economical solution, aims to reduce resource consumption and environmental impact by reusing reclaimed asphalt pavement (RAP). However, this technology faces an obvious challenge - the limited mixing ratio of old materials. In conventional operations, the mixing ratio of RAP usually does not exceed 30%, mainly because the performance of recycled mixtures with high mixing ratios often fails to meet engineering requirements, especially in terms of low-temperature performance. This action plan advocates strengthening the large mixing ratio, large-scale and high-value utilization of bulk solid waste to promote resource recycling and emission reduction. Therefore, there is an urgent need to develop innovative processes and design methods that can not only ensure pavement performance but also increase the mixing ratio of old materials. Summary of the Invention

[0003] The present invention provides a method for determining the heating temperature of hot recycled old materials and a heating temperature determination system to solve the problem of determining the heating temperature of hot recycled old materials in the prior art and provide technical support for the application of hot recycled asphalt mixtures with a high mixing ratio of old materials.

[0004] The present invention provides a method for determining the heating temperature of hot recycled old materials, which includes the following steps:

[0005] Placing more than one portion of asphalt old materials at different heating temperatures for a preset time;

[0006] Recycling the heated asphalt old materials to obtain old asphalt specimens at different heating temperatures;

[0007] Conducting a multiple stress creep and recovery test on the old asphalt specimens at different heating temperatures and analyzing the test results by the significant F-test method to obtain the upper limit of the heating design temperature of the asphalt old materials;

[0008] Preparing standard Marshall specimens at different heating temperatures using the heated asphalt old materials and testing the high-temperature, low-temperature and fatigue performance of the standard Marshall specimens to obtain the lower limit of the heating design temperature of the asphalt old materials;

[0009] Calculating the average value of the upper limit of the heating design temperature of the asphalt old materials and the lower limit of the heating design temperature of the asphalt old materials, and taking this average value as the heating temperature of the hot recycled old materials.

[0010] According to the method for determining the heating temperature of recycled old materials provided by the present invention, the process of recycling the heated asphalt old materials to obtain old asphalt specimens at different heating temperatures is as follows:

[0011] Use a trichloroethylene extraction device to separate the old asphalt on the surface of the heated asphalt old materials to obtain a mixture of trichloroethylene and old asphalt;

[0012] Use an Abson asphalt recovery device to recover clean old asphalt specimens at different heating temperatures from the mixture of trichloroethylene and old asphalt.

[0013] Furthermore, the process of obtaining the upper limit of the heating design temperature of the asphalt old materials is as follows:

[0014] Use a dynamic shear rheometer DSR to conduct a multi-stress creep recovery test on the old asphalt specimens at different heating temperatures to obtain the results of the non-recoverable creep compliance of the old asphalt at different heating temperatures;

[0015] Analyze the obtained results of the non-recoverable creep compliance by the significant F-test method, obtain the temperature corresponding to the significant decrease in the results at different heating temperatures, and use the heating temperature at the temperature inflection point as the upper limit of the heating design temperature of the asphalt old materials.

[0016] Even further, the process of obtaining the lower limit of the heating design temperature of the asphalt old materials is as follows:

[0017] Use the heated asphalt old materials, new aggregates, new asphalt, and regenerant to mix and prepare a recycled mixture according to a preset ratio;

[0018] Use the compaction method to form the recycled mixture to obtain standard Marshall specimens at different heating temperatures;

[0019] Conduct high-temperature, low-temperature, and fatigue performance tests on the standard Marshall specimens at different heating temperatures, and calculate the lower limit of the heating design temperature of the asphalt old materials by back-calculation based on the standard limits of high-temperature performance, low-temperature performance, and fatigue performance.

[0020] Even further, the process of calculating the lower limit of the heating design temperature of the asphalt old materials by back-calculation based on the standard limits of high-temperature performance, low-temperature performance, and fatigue performance is as follows:

[0021] Establish a nomograph of the road performance of standard Marshall specimens under the combination of the heating temperature and blending ratio of asphalt old materials;

[0022] Based on the design traffic volume, climate environment data, and information on the designed structural layer position, obtain the high-temperature, low-temperature, and fatigue performance indicators required for the design;

[0023] Obtain the lower limit of the heating design temperature of the asphalt old materials according to the high-temperature, low-temperature, and fatigue performance indicators required for the design.

[0024] Furthermore, the high temperature, low temperature and fatigue performance indexes required for design obtained based on the road structure layer, meteorological and traffic data are as follows:

[0025] In terms of high temperature performance, the dynamic stability of the prepared standard Marshall specimen should be greater than 5000 times / mm; in terms of low temperature performance, the low temperature fracture energy of the prepared standard Marshall specimen should be greater than 1075 KJ / m 2 ; in terms of fatigue performance, the fatigue life of the prepared standard Marshall specimen is greater than or equal to 107913 times.

[0026] Furthermore, the heating temperature of the recycled old material is the average value of the upper limit and the lower limit of the heating design temperature of the asphalt old material;

[0027] T mean =(T 1 +T 2 ) / 2,

[0028] wherein, T mean represents the average value, T 1 represents the upper limit of the heating design temperature of the asphalt old material, and T 2 represents the lower limit of the heating design temperature of the asphalt old material.

[0029] The present invention also provides a system for determining the heating temperature of recycled old material, which adopts the method for determining the heating temperature of recycled old material described in any one of the above, and includes a heating device, a recycling device, a test analysis device, a testing device and a calculation device;

[0030] The heating device is used to heat the asphalt old material for a preset time at different heating temperatures;

[0031] The recycling device is used to recycle the heated asphalt old material to obtain old asphalt specimens at different heating temperatures;

[0032] The test analysis device is used to perform a multiple stress creep recovery test on the old asphalt specimens at different heating temperatures, and analyze the test results by the significance F test method to obtain the upper limit of the heating design temperature of the asphalt old material;

[0033] The testing device is used to prepare standard Marshall specimens at different heating temperatures according to the heated asphalt old material, and perform high temperature, low temperature and fatigue performance tests on the standard Marshall specimens to obtain the lower limit of the heating design temperature of the asphalt old material;

[0034] The calculation device is used to calculate the average value of the upper limit and the lower limit of the heating design temperature of the asphalt old material, and use this average value as the heating temperature of the recycled old material.

[0035] The method for determining the heating temperature of recycled old materials provided by the present invention conducts multiple stress creep and recovery tests on old asphalt specimens at different heating temperatures, and analyzes the test results by the significant F - test method to obtain the upper limit of the heating design temperature of the old asphalt materials; uses the heated old asphalt materials to prepare standard Marshall specimens at different heating temperatures, and conducts high - temperature, low - temperature and fatigue performance tests on the standard Marshall specimens to obtain the lower limit of the heating design temperature of the old asphalt materials; calculates the average value of the upper limit of the heating design temperature of the old asphalt materials and the lower limit of the heating design temperature of the old asphalt materials, and takes this average value as the heating temperature of the recycled old materials. The present invention can scientifically and reasonably determine the heating temperature of the recycled old materials, effectively prevent the secondary aging problem of the old asphalt, and at the same time solve the technical problem that the road - using performance of plant - mix hot - recycled asphalt mixtures with a high old - material content is difficult to meet the specification requirements, providing theoretical support for improving the effective utilization of old materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0037] Figure 1 is the flow chart of the method for determining the heating temperature of recycled old materials provided by the present invention;

[0038] Figure 2 are the test results of MSCR (Multiple Stress Creep and Recovery) of asphalt in RAP at different heating temperatures;

[0039] Figure 3 is the nomograph of the influence of the heating temperature of old materials on the road - using performance of the prepared standard Marshall specimens under different old - material contents; among them, Figure (a) is the nomograph of the road - using performance of Marshall specimens drawn according to the high - temperature performance of standard Marshall specimens under different old - material contents; Figure (b) is the nomograph of the road - using performance of standard Marshall specimens drawn according to the low - temperature performance of standard Marshall specimens under different old - material contents; Figure (c) is the nomograph of the road - using performance of standard Marshall specimens drawn according to the fatigue performance of standard Marshall specimens under different old - material contents;

[0040] Figure 4 is the schematic diagram of the result of determining the lower limit of the heating temperature of old materials under different old - material contents based on performance;

[0041] Figure 5 is the structural block diagram of the system for determining the heating temperature of recycled old materials provided by the present invention.

[0042] Description of reference numerals:

[0043] 10. Heating device; 20. Recovery device; 30. Test and analysis device; 40. Testing device; 50. Calculation device. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] In the existing technology, one of the main reasons that limits the increase in the mixing rate of old materials is the insufficient preheating temperature of the old materials. According to the "Technical Specifications for Highway Asphalt Pavement Regeneration", the recommended heating temperature range for recycled materials in asphalt mixtures is 110℃~130℃, but in actual construction, affected by various factors such as equipment capacity, energy efficiency and operating conditions, the heating temperature of recycled materials is often difficult to reach the ideal level. The low preheating temperature affects the performance recovery of old asphalt materials, thereby restricting the use ratio of RAP in recycled mixtures.

[0046] In addition, the existing design method of recycled mixtures relies too much on volumetric indicators and lacks sufficient consideration of performance-oriented design. This method ignores the differences in the behavior of recycled mixtures under different temperature conditions, especially that high-temperature performance is usually excessive, while low-temperature performance is often insufficient, which poses a challenge to ensuring the long-term stability and durability of recycled pavement.

[0047] In order to solve these problems, future research and development will focus on optimizing preheating technology and design methods. On the one hand, the preheating temperature of RAP is increased to ensure that the asphalt in the old material can be effectively softened and restore its original adhesion and fluidity. On the other hand, a performance-based design method is developed, focusing on improving the overall performance of recycled mixtures under actual use conditions, especially crack resistance and durability under low temperature conditions. Through these improvement measures, not only can the blending rate of RAP be increased, but also the recycled pavement materials can be ensured to perform well under various climates and traffic loads, thereby promoting the development of green and low-carbon transportation infrastructure.

[0048] Combine the following Figure 1 The invention provides a method for determining the heating temperature of thermally regenerated waste materials, which is designed based on aging and performance balance.

[0049] like Figure 1 As shown, the method for determining the heating temperature of hot recycled waste materials provided by the present invention comprises the following steps:

[0050] S1. Place more than one portion of recycled asphalt materials at different heating temperatures for a preset time.

[0051] Specifically, recycled asphalt materials can be obtained by recycling waste asphalt materials from the road surface, and the obtained recycled asphalt materials are dried. Then, more than one portion of the dried recycled asphalt materials are respectively placed in an oven at different heating temperatures for heating, and the heating time can be 2 hours. It can be understood that the corresponding heating time can also be set according to process requirements.

[0052] S2. Recycle the heated recycled asphalt materials to obtain clean recycled asphalt specimens at different heating temperatures.

[0053] Specifically, a trichloroethylene extraction device can be used to separate the old asphalt on the surface of the heated recycled asphalt materials to obtain a mixture of trichloroethylene and old asphalt. Then, an Abson asphalt recycling device is used to recycle clean recycled asphalt specimens at different heating temperatures from the mixture of trichloroethylene and old asphalt.

[0054] S3. Conduct multiple stress creep recovery tests on the clean recycled asphalt specimens at different heating temperatures respectively, and analyze the test results by the significant F - test method to obtain the upper limit T of the heating design temperature of the recycled asphalt materials. 1 ;

[0055] Specifically, a DSR (Dynamic Shear Rheometer) is used to conduct multiple stress creep recovery tests on the recycled asphalt specimens at different heating temperatures respectively, and the unrecoverable creep compliance J of the recycled asphalt at different heating temperatures is obtained. nr Result.

[0056] Analyze the obtained unrecoverable creep compliance J nr results by the significant F - test method, obtain the temperature corresponding to the significant decrease in the results at different heating temperatures (i.e., significant secondary aging of the old asphalt), and take the heating temperature that is less than this temperature and has the smallest difference from this temperature as the upper limit T of the heating design temperature of the recycled asphalt materials. 1 .

[0057] S4. Use the heated recycled asphalt materials to prepare standard Marshall specimens at different heating temperatures, and conduct high - temperature, low - temperature and fatigue performance tests on the standard Marshall specimens to obtain the lower limit T of the heating design temperature of the recycled asphalt materials. 2 ;

[0058] Specifically, use the recycled asphalt materials heated in step S1, new aggregates, new asphalt and recycling agent to mix and prepare a recycled mixture according to a preset ratio.

[0059] Use the compaction method to form the recycled mixture to obtain standard Marshall specimens at different heating temperatures.

[0060] Standard Marshall specimens at different heating temperatures are tested for high-temperature, low-temperature, and fatigue performance, and the lower limit of the heating design temperature T of the old asphalt mixture is calculated by back-calculation based on the standard limits of high-temperature performance (i.e., rutting dynamic stability index), low-temperature performance (i.e., low-temperature fracture energy index), and fatigue performance (i.e., splitting fatigue life index). 2 .

[0061] S5. Calculate the upper limit T of the heating design temperature of the old asphalt mixture 1 and the lower limit T of the heating design temperature of the old asphalt mixture 2 and take the average value as the heating temperature of the recycled old mixture.

[0062] Specifically, the average value of the upper limit T of the heating design temperature of the old asphalt mixture 1 and the lower limit T of the heating design temperature of the old asphalt mixture 2 is: T mean =(T 1 +T 2 ) / 2.

[0063] In the above step S4, the specific process of calculating the lower limit T of the heating design temperature of the old asphalt mixture by back-calculation based on the standard limits of high-temperature performance, low-temperature performance, and fatigue performance is as follows: 2 :

[0064] S41. Establish a nomograph of the road performance of standard Marshall specimens under the combination of the heating temperature and blending ratio of the old asphalt mixture.

[0065] S42. Based on the design traffic volume, climate environment data, and design structural layer information, obtain the required high-temperature, low-temperature, and fatigue performance indicators.

[0066] S43. Obtain the lower limit T of the heating design temperature of the old asphalt mixture according to the required high-temperature, low-temperature, and fatigue performance indicators 2 .

[0067] To facilitate a clearer and more intuitive understanding of the method for determining the heating temperature of the recycled old mixture provided by the present invention, the following is illustrated by a specific embodiment.

[0068] Taking a first-class highway in Shanxi Province as an example, the application of the method for determining the heating temperature of the recycled old mixture provided by the present invention is specifically introduced.

[0069] In this application case, recycled asphalt pavement materials (RAP materials) from a highway that has been in service for more than 10 years are used, combined with a new type of high-performance SBS modified asphalt and new aggregates, aiming to improve the durability of the pavement. Among them, the new aggregates are subdivided into four grades according to different particle sizes, and the material selection for each grade takes into account its unique mechanical properties:

[0070] The new aggregate with a particle size of 0 - 3 mm is limestone. Such fine particles are suitable for filling voids and enhancing the density of the mixture.

[0071] The new aggregate with a particle size of 3 - 5 mm is also limestone. The particles in this range can provide additional structural stability while maintaining a good gradation.

[0072] The new aggregate with a particle size of 5 - 10 mm is basalt with higher hardness. Such medium-sized particles can significantly increase the compressive strength and wear resistance of the mixture.

[0073] The new aggregate with a particle size of 10 - 15 mm is also basalt. The large-sized basalt can play a role as a skeleton in the mixture, enhancing the stability and bearing capacity of the overall structure.

[0074] The following method is used to prepare high - content plant - mixed hot standard Marshall specimens, and the specific process is as follows:

[0075] S11. Recycle the waste asphalt material from the pavement to obtain asphalt old material. Dry the obtained asphalt old material, and place the dried asphalt old material in an oven at different heating temperatures for heating. The heating time can be set to 2 hours.

[0076] S22. Use a trichloroethylene extraction device to separate the old asphalt on the surface of the heated asphalt old material to obtain a mixture of trichloroethylene and old asphalt; then use an Abson asphalt recovery device to recover clean old asphalt specimens at different heating temperatures from the mixture of trichloroethylene and old asphalt.

[0077] S33. Use DSR to conduct multiple stress creep recovery tests on the old asphalt specimens at different heating temperatures to obtain the non - recoverable creep compliance J of the old asphalt at different heating temperatures. nr Results. Among them, when conducting the multiple stress creep recovery test, the test temperatures are set to 58 °C, 64 °C, 70 °C, and 76 °C.

[0078] For the obtained non - recoverable creep compliance J nr results, conduct a significance F - test method analysis. The analysis results are as Figure 2 shown in Table 1.

[0079] From Figure 2 it can be seen that at the four test temperatures of 58 °C, 64 °C, 70 °C, and 76 °C, when the heating temperature is less than or equal to 160 °C, the non - recoverable creep compliance J of the recycled asphalt in RAP under the stresses of 0.1 kPa and 3.2 kPa nr does not change significantly. However, when the heating temperature is 160 °C - 180 °C, the J of the recycled asphalt in RAP nr0.1 and Jnr3.2 All decreased significantly. Taking the test temperature of 58 °C as an example, compared with the unheated RAP material, the J of the recovered asphalt in the RAP after heating at 180 °C nr0.1 and J nr3.2 decreased by 10.4% and 15.3% respectively. Relevant research shows that the unrecoverable creep compliance J nr of asphalt will decrease after aging. Therefore, it is reasonable to believe that when the heating temperature of the RAP material is less than or equal to 160 °C, increasing the heating temperature of the RAP will not cause secondary aging of the old asphalt, while when the heating temperature reaches 180 °C, a certain degree of secondary aging of the old asphalt occurs.

[0080] Table 1 Calculation results of the test statistic of the F test

[0081]

[0082]

[0083] In Table 1, J nr0.1 represents the average value of the unrecoverable creep compliance J nr values obtained within 10 creep recovery cycles under a stress level of 0.1 kPa, and J nr3.2 represents the average value of the unrecoverable creep compliance J nr values obtained within 10 creep recovery cycles under a stress level of 3.2 kPa; R 0.1 represents the average value of the creep recovery rate R values obtained within 10 creep recovery cycles under a stress level of 0.1 kPa, and R 3.2 represents the average value of the creep recovery rate R values obtained within 10 creep recovery cycles under a stress level of 3.2 kPa.

[0084] It can be seen from Table 1 that at a significance level of 0.05, it can be considered that there are significant differences in the unrecoverable creep compliance J nr of the recovered asphalt in the RAP at six heating temperatures under stresses of 0.1 kPa and 3.2 kPa. At the same time, at a significance level of 0.05, it can be considered that when the heating temperature is less than or equal to 160 °C, there are no significant differences in the recovery rate and the unrecoverable creep compliance J nr of the recovered asphalt in the RAP after heating at different temperatures under stresses of 0.1 kPa and 3.2 kPa. That is, when the heating temperature of the RAP is less than or equal to 160 °C, increasing the heating temperature of the RAP will not cause secondary aging of the old asphalt, but when the heating temperature exceeds the 160 °C threshold and reaches 180 °C, secondary aging of the old asphalt will occur at this heating temperature.

[0085] Therefore, in this embodiment, 160 °C is taken as the upper limit T 1 of the heating design temperature of the old material.

[0086] S44. Obtain standard Marshall specimens at different heating temperatures from the heated asphalt reclaimed materials; test the high-temperature performance, low-temperature performance, and fatigue performance of the standard Marshall specimens with different reclaimed material dosages, as Figure 3 shown, and draw the nomograph of the pavement performance of the standard Marshall specimens; based on the design traffic volume, climate environment data, and the information of the designed structural layer, obtain the performance design target requirements of the standard Marshall specimens.

[0087] Among them, based on the road structural layer, meteorological, and traffic data, the indoor performance target values required for design are:

[0088] In terms of high-temperature performance, the dynamic stability of the prepared standard Marshall specimens should be greater than 5000 times / mm; in terms of low-temperature performance, the low-temperature fracture energy of the prepared standard Marshall specimens should be greater than 1075 KJ / m 2 ; in terms of fatigue performance, the fatigue life of the prepared standard Marshall specimens is greater than or equal to 107913 times.

[0089] The final design combination plan should simultaneously meet the design target requirements of high-temperature performance, low-temperature performance, and fatigue performance. According to the performance design target requirements of the standard Marshall specimens, as Figure 3 shown, find the lower limit T of the reclaimed material heating design temperature corresponding to different reclaimed material dosages in the nomograph 2 .

[0090] As Figure 4 shown, the comprehensive nomographs of high-temperature performance, low-temperature performance, and fatigue performance. It can be seen that the combinations with better high-temperature performance are mainly distributed in the upper right part of the image of the reclaimed material heating temperature under different reclaimed material dosages; the combinations with better low-temperature performance are mainly distributed in the lower left area and the upper right corner area of the image of the reclaimed material heating temperature under different reclaimed material dosages; the combinations with better fatigue performance are mainly distributed in the upper right corner area of the image of the reclaimed material heating temperature under different reclaimed material dosages. Among them, the abscissa of the image of the reclaimed material heating temperature under different reclaimed material dosages represents the reclaimed material dosage, and the ordinate represents the reclaimed material heating temperature.

[0091] It is not difficult to see that it is completely possible to Figure 4 select an area with the best comprehensive performance in the image of the reclaimed material heating temperature under different reclaimed material dosages shown. The implementation method is high-temperature heating regeneration of the reclaimed material. In this area, the reclaimed material heating temperature reaches 150 - 160 °C, the reclaimed material blending ratio can reach 70% - 80%, and the performances in terms of high-temperature performance, low-temperature performance, and fatigue performance all reach good levels, realizing the improvement of the performance of the prepared standard Marshall specimens and the balance between performance and reclaimed material dosage.

[0092] Therefore, in this embodiment, the lower limit T of the reclaimed material heating design temperature corresponding to 80% reclaimed material dosage2 is 150 °C.

[0093] S55. Calculate the average value T of the upper limit and the lower limit of the designed heating temperature of the recycled materials mean :

[0094] T mean = (T 1 + T 2 ) / 2,

[0095] and use the average value T mean as the heating temperature of the recycled hot mix materials.

[0096] In this embodiment, at an old material content of 80%, the upper limit T of the designed heating temperature of the recycled materials that can ensure no secondary aging of the old asphalt 1 is 160 °C, and the lower limit T of the designed heating temperature of the recycled materials that can meet the high-temperature performance, low-temperature performance, and fatigue performance 2 is 150 °C. Therefore, in this embodiment, the optimal heating temperature of the recycled hot mix materials is (150 + 160) / 2 = 155 °C.

[0097] It can be seen from the above embodiments that by using the method for determining the heating temperature of recycled hot mix materials based on the balance between aging and performance proposed in the present invention, the problem of secondary aging of old asphalt can be effectively prevented, and at the same time, the technical problem that the road performance of plant-mixed hot recycled asphalt mixtures with a high old material content is difficult to meet the specification requirements can be solved, providing a theoretical support for improving the effective utilization of old materials.

[0098] In an exemplary embodiment, as Figure 5 shown, based on the method for determining the heating temperature of recycled hot mix materials provided by the present invention, the present invention also provides a system for determining the heating temperature of recycled hot mix materials, which includes a heating device 10, a recycling device 20, a test and analysis device 30, a testing device 40, and a calculation device 50.

[0099] The heating device 10 is used to heat the asphalt recycled materials at different heating temperatures for a preset time;

[0100] The recycling device 20 is used to recycle the heated asphalt recycled materials to obtain clean old asphalt specimens at different heating temperatures;

[0101] The test and analysis device 30 is used to conduct a multi-stress creep and recovery test on the clean old asphalt specimens at different heating temperatures, and analyze the test results by the significance F-test method to obtain the upper limit T of the designed heating temperature of the asphalt recycled materials 1 ;

[0102] A testing device 40 is used to obtain standard Marshall specimens at different heating temperatures from the recycled asphalt mixture after heating, and conduct high-temperature, low-temperature, and fatigue performance tests on the standard Marshall specimens to obtain the lower limit T of the heating design temperature of the recycled asphalt mixture. 2 ;

[0103] A calculation device 50 is used to calculate the upper limit T of the heating design temperature of the recycled asphalt mixture 1 and the lower limit T of the heating design temperature of the recycled asphalt mixture 2 and take the average value as the heating temperature of the recycled asphalt mixture.

[0104] It should be noted that the system for determining the heating temperature of the recycled asphalt mixture provided in the above embodiment and the embodiment of the method for determining the heating temperature of the recycled asphalt mixture belong to the same concept. The specific implementation process can be found in the method embodiment and will not be elaborated here.

[0105] The device embodiments described above are merely illustrative. 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 to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative work.

[0106] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the essence of the above technical solution, or the part that contributes to the prior art, can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for determining the heating temperature of thermally regenerated waste materials, characterized in that: The following steps are involved: More than one portion of used asphalt material is placed at different heating temperatures and heated for a preset time; The heated old asphalt material is recycled to obtain old asphalt samples at different heating temperatures. The process is as follows: A trichloroethylene extraction device is used to separate the old asphalt on the surface of the heated old asphalt material to obtain a mixed liquid of trichloroethylene and old asphalt; The clean old asphalt samples at different heating temperatures were recovered from the mixture of trichloroethylene and old asphalt using the Absen asphalt recovery device. Multiple stress creep recovery tests were carried out on old asphalt samples at different heating temperatures, and the test results were analyzed by the significance F test method to obtain the upper limit of the heating design temperature of old asphalt materials. The process is as follows: The dynamic shear rheometer DSR was used to conduct multiple stress creep recovery tests on old asphalt samples at different heating temperatures, and the irrecoverable creep compliance results of old asphalt at different heating temperatures were obtained. The irreversible creep compliance results were analyzed by the significance F test method to obtain the temperature corresponding to the significant decrease of the results at different heating temperatures. The heating temperature at the temperature inflection point was used as the upper limit of the heating design temperature of the asphalt waste material. The heated old asphalt material is used to prepare standard Marshall specimens at different heating temperatures, and the standard Marshall specimens are subjected to high temperature, low temperature and fatigue performance tests to obtain the lower limit of the heating design temperature of the old asphalt material. The process is as follows: The heated old asphalt material, new aggregate, new asphalt and regeneration agent are mixed in a preset proportion to obtain a recycled mixture; The recycled mixture was molded by compaction method to obtain standard Marshall specimens at different heating temperatures. Conduct high temperature, low temperature and fatigue performance tests on standard Marshall specimens at different heating temperatures, and calculate the lower limit of the heating design temperature of used asphalt materials based on the standard limits of high temperature performance, low temperature performance and fatigue performance; Calculate the average value of the upper and lower design temperatures for heating of used asphalt materials, and use the average value as the heating temperature for hot recycled materials.

2. The method for determining the heating temperature of thermally regenerated waste materials according to claim 1, characterized in that: The process of back-calculating the lower limit of the design temperature for heating of used asphalt materials based on the standard limit of high temperature performance, the standard limit of low temperature performance and the standard limit of fatigue performance is as follows: Establish the road performance nomogram of standard Marshall specimens under the combination of heating temperature and blending ratio of asphalt waste material; Based on the designed traffic volume, climate and environmental data and the designed structural layer information, the high temperature, low temperature and fatigue performance indicators required for the design are obtained; The lower limit of the design temperature for heating old asphalt materials is obtained based on the high temperature, low temperature and fatigue performance indicators required by the design.

3. The method for determining the heating temperature of thermally regenerated waste materials according to claim 2, characterized in that: Based on the road structure layer and meteorological and traffic data, the high temperature, low temperature and fatigue performance indicators required for the design are obtained as follows: In terms of high temperature performance, the dynamic stability of the standard Marshall specimen must be greater than 5000 times / mm; in terms of low temperature performance, the low temperature fracture energy of the standard Marshall specimen must be greater than 1075KJ / m 2 In terms of fatigue performance, the fatigue life of the standard Marshall specimen is greater than or equal to 107913 times.

4. The method for determining the heating temperature of thermally regenerated waste materials according to claim 1, characterized in that: The heating temperature of the hot recycled waste material is the average of the upper design temperature of the asphalt waste material heating and the lower design temperature of the asphalt waste material heating; T mean =(T1+T2) / 2, Where, T mean Represents the average value, T1 represents the upper limit of the design temperature for heating of used asphalt materials, and T1 represents the lower limit of the design temperature for heating of used asphalt materials.

5. A system for determining the heating temperature of hot recycled waste material using the method for determining the heating temperature of hot recycled waste material according to any one of claims 1 to 4, characterized in that: It includes heating device, recovery device, test and analysis device, testing device and calculation device; The heating device is used to heat the asphalt waste material for a preset time at different heating temperatures; The recycling device is used to recycle the heated old asphalt material to obtain old asphalt samples at different heating temperatures; The test analysis device is used to perform multiple stress creep recovery tests on old asphalt samples at different heating temperatures, and analyze the test results using the significance F test method to obtain the upper limit of the heating design temperature of the old asphalt material; The testing device is used to prepare standard Marshall specimens at different heating temperatures based on the heated old asphalt material, and to perform high temperature, low temperature and fatigue performance tests on the standard Marshall specimens to obtain the lower limit of the heating design temperature of the old asphalt material; The calculation device is used to calculate the average value of the upper limit of the heating design temperature of the asphalt waste material and the lower limit of the heating design temperature of the asphalt waste material, and use the average value as the heating temperature of the hot recycled waste material.

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