Method and device for determining change rule of asphalt pavement material strain rate with road age
By conducting multi-sequence local loading tests and mathematical fitting on asphalt pavement core samples, the shortcomings of traditional evaluation methods in predicting strain rate development patterns were overcome. This enabled the determination of the stage-by-stage variation patterns of strain rate, supporting scientific maintenance decisions and cost savings.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SOUTH CHINA UNIV OF TECH
- Filing Date
- 2023-07-05
- Publication Date
- 2026-06-02
Smart Images
Figure CN116754405B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of road maintenance, and in particular to a method and apparatus for determining the variation law of strain rate of asphalt pavement material with road age. Background Technology
[0002] Traditional methods for evaluating the high-temperature performance of core samples from in-service asphalt pavements suffer from two drawbacks: ① Core samples are typically taken only from the wheel track area of the pavement, and then subjected to indoor high-temperature performance tests to obtain evaluation indicators, such as repeated creep tests to determine the number of rheological cycles. Traditional evaluation methods and indicators can only compare the high-temperature performance of the core samples, but cannot reconstruct or predict the current high-temperature performance development pattern of the cored section. Since the development of a complete high-temperature performance (i.e., permanent strain rate) of asphalt mixtures is a process of initial enhancement followed by decline, consisting of two stages: an initial performance enhancement stage and a decline stage, predicting the performance development pattern requires not only identifying an initial performance point but also reasonably predicting and determining the performance transition point (i.e., the minimum value of permanent strain rate). Due to limitations in maintenance and management, there are no records of the initial performance points of pavements when they are put into use. Furthermore, current research on the prediction of high-temperature performance or rutting damage of pavements is mostly based on indoor molding of new materials, with only qualitative evaluations and a lack of quantitative analysis for core samples. Therefore, existing research cannot determine the strain rate development law of core pavements. Secondly, traditional high-temperature performance tests can only apply a single stress level of loading to the material. However, actual road traffic conditions are complex, and the impact of heavy loads and overloads on the performance of asphalt pavement materials cannot be ignored. In other words, the strain rate development law of asphalt pavement materials differs significantly under different traffic levels. For example, the development of permanent strain rate under heavy loads precedes its performance development under medium and low traffic axle loads. Therefore, the strain rate development law of asphalt pavement materials should be differentiated according to different traffic axle loads, which requires considering stress level variations when conducting indoor performance tests on core samples. Summary of the Invention
[0003] In order to at least partially solve one of the technical problems existing in the prior art, the purpose of this invention is to provide a method and apparatus for determining the variation law of strain rate of asphalt pavement material with road age.
[0004] The technical solution adopted in this invention is:
[0005] A method for determining the variation of strain rate of asphalt pavement materials with pavement age includes the following steps:
[0006] S1. Conduct multi-sequence local loading tests on pavement core specimens;
[0007] S2. Based on the cumulative permanent strain curve obtained from the experiment, the slope of the cumulative strain changing with time is fitted as the strain rate. Unit: με / s;
[0008] S3. Calculate the ratio of the wheel track strain rate to the shoulder strain rate under different stress levels, denoted as A;
[0009] S4. Set three points respectively. Point A represents the strain rate of the pavement material in the first year after the road opened to traffic. Point B represents the minimum material strain rate in the k-th year after the line opens to traffic. Point C represents the strain rate of the material in the year the core was taken, i.e., when the road age is n.
[0010] S5. Let x = 2, 3, 4…n-1. Starting from A and ending at B, fit n-2 power functions, denoted as f. j (x), j = 1, 2, 3…n-2;
[0011] S6. Let x = 2, 3, 4…n-1, and with B as the starting point and C as the ending point, fit n-2 exponential functions, denoted as g. j (x), j = 1, 2, 3…n-2;
[0012] S7, respectively for f j (x) and g j Differentiating (x) yields the derivative function f. j ′ (x) and g j ′ (x);
[0013] S8. Define D(x) = |f j ′ (x)-|g j ′ Calculate the value of D(x) when x = 2, 3, 4...n-1;
[0014] S9. Determine the value of x when |D(x)| reaches its minimum value, at which point x = k. This uniquely determines a set of phased variation patterns of pavement material strain rate with pavement age, i.e., when 1 < x ≤ k. When x≥k
[0015] Furthermore, the highway where the pavement core sample is located in step S1 should be at least 8 years old, and the core section should not have been milled and repaved during its service life.
[0016] Furthermore, the pavement core samples mentioned in step S1 include core samples from the wheel track area and the shoulder area, and the core samples from the wheel track area and the shoulder area are taken from the same traffic section of the same highway. In addition, the core sampling locations have the same maintenance history.
[0017] Further, step S1 includes:
[0018] The road surface core sample was divided into upper, middle and lower layers, and then a multi-sequence local loading test was performed on the sample of each layer.
[0019] Furthermore, the test temperatures of specimens at different layers are maintained at a preset temperature difference;
[0020] The test temperature range for the top layer is 60–65℃, for the middle layer it is 55–60℃, and for the bottom layer it is 50–55℃.
[0021] Furthermore, the multi-sequence local loading described in step S1 includes two loading stages: preloading and multi-stress loading. In the preloading stage, only one stress level and a fixed number of repeated loading sequences are set. In the multi-stress loading stage, at least three different stress magnitudes but with the same number of repeated loading sequences are set.
[0022] Furthermore, the parameter settings for the loading schemes of the same layer shoulder and wheel track core samples in the multi-sequence local loading test described in step S1 are consistent.
[0023] Furthermore, in step S3, the value of A increases with the increase of stress level.
[0024] Furthermore, in step S4 The strain rate value is taken for the core sample at the wheel track. The strain rate value is taken for the core sample at the road shoulder.
[0025] Furthermore, in step S4, the minimum value of the material strain rate within N years of operation. The range of values is within Between. Preferably, Pick
[0026] Another technical solution adopted in this invention is:
[0027] A device for determining the variation law of strain rate of asphalt pavement material with road age, comprising:
[0028] At least one processor;
[0029] At least one memory for storing at least one program;
[0030] When the at least one program is executed by the at least one processor, the at least one processor performs the method as described above.
[0031] Another technical solution adopted in this invention is:
[0032] A computer-readable storage medium storing a processor-executable program, which, when executed by a processor, performs the method described above.
[0033] The beneficial effects of this invention are: this invention can comprehensively and effectively determine the strain rate development law of actual asphalt pavement based on the traffic characteristics of the actual pavement, helping road management units to formulate scientific and refined maintenance strategies for pavement rutting defects and save maintenance costs. Attached Figure Description
[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following description is provided with accompanying drawings of the relevant technical solutions in the embodiments of the present invention or the prior art. It should be understood that the accompanying drawings described below are only for the purpose of clearly illustrating some embodiments of the technical solutions of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0035] Figure 1 This is a schematic diagram of the stress setting for the multi-sequence local loading test in an embodiment of the present invention;
[0036] Figure 2 This is a schematic diagram of the cumulative strain curve of the Lianxu mid-surface layer specimen under multi-sequence local loading in an embodiment of the present invention;
[0037] Figure 3 This is a schematic diagram of the power function fitting curve between A and B under a stress of 0.7 MPa in an embodiment of the present invention;
[0038] Figure 4 This is a schematic diagram of the power function fitting curve between A and B under a stress of 1.0 MPa in an embodiment of the present invention;
[0039] Figure 5 This is a schematic diagram of the power function fitting curve between A and B under a stress of 1.2 MPa in an embodiment of the present invention;
[0040] Figure 6 This is a schematic diagram of the exponential function fitting curve between B and C under a stress of 0.7 MPa in an embodiment of the present invention;
[0041] Figure 7 This is a schematic diagram of the exponential function fitting curve between B and C under a stress of 1.0 MPa in an embodiment of the present invention;
[0042] Figure 8This is a schematic diagram of the exponential function fitting curve between B and C under a stress of 1.2 MPa in an embodiment of the present invention. Detailed Implementation
[0043] The embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. The step numbers in the following embodiments are set only for ease of explanation, and there is no limitation on the order between the steps. The execution order of each step in the embodiments can be adaptively adjusted according to the understanding of those skilled in the art.
[0044] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.
[0045] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.
[0046] Furthermore, in the description of this invention, unless otherwise stated, "multiple" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.
[0047] In the description of this invention, unless otherwise explicitly defined, terms such as "setting," "installing," and "connecting" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.
[0048] Determining the strain rate development law of asphalt pavement is crucial for maintenance decisions regarding pavement rutting resistance, as it relates to the scientific and rational allocation of millions or even tens of millions of yuan in annual maintenance costs. To address the problems in maintenance management more scientifically and efficiently, this invention proposes a method for determining the strain rate variation law of asphalt pavement materials with pavement age. This method uses the strain rate obtained from multi-sequence local loading tests on core samples at the road shoulder as the starting point for the strain rate. Secondly, based on extensive preliminary project research, the range of minimum strain rate values is determined, effectively solving the first drawback mentioned above. Furthermore, the multi-sequence local loading tests used in this invention can obtain the strain rate of the material under various stress levels, thus enabling a comprehensive summary of the strain rate development law of asphalt pavement materials throughout their service life under different traffic levels, resulting in more comprehensive, complete, and reliable evaluation results.
[0049] This embodiment provides a method for determining the variation law of strain rate of asphalt pavement material with road age, including the following steps:
[0050] 1) Conduct multi-sequence local loading tests on pavement core specimens;
[0051] 2) Based on the cumulative permanent strain curve obtained from the above experiments, fit the slope of the cumulative strain changing with time, i.e., the strain rate. Unit: με / s;
[0052] 3) Calculate the ratio of the strain rate of the wheel track to the strain rate of the shoulder under different stress levels, denoted as A;
[0053] 4) Set up three points respectively Point A represents the strain rate of the pavement material in the first year after the road opened to traffic. Point B represents the minimum material strain rate in the k-th year after the line opens to traffic. Point C represents the strain rate of the material in the year the core was taken, i.e., when the road age is n.
[0054] 5) Let x = 2, 3, 4…n-1, and with A as the starting point and B as the ending point, fit n-2 power functions respectively, denoted as f. j (x), j = 1, 2, 3…n-2;
[0055] 6) Similarly, let x = 2, 3, 4…n-1, and with B as the starting point and C as the ending point, fit n-2 exponential functions respectively, denoted as g. j (x), j = 1, 2, 3…n-2;
[0056] 7) For f respectively j (x) and g j Differentiating (x) yields the derivative function f. j ′ (x) and gj ′ (x);
[0057] 8) Define D(x) = |f j ′ (x)-|g j ′ Calculate the value of D(x) when x = 2, 3, 4...n-1;
[0058] 9) Determine the value of x when |D(x)| reaches its minimum value, at which point x = k. This uniquely determines a set of phased variation laws of pavement material strain rate with pavement age, i.e., when 1 < x ≤ k. When x≥k
[0059] This embodiment of the method involves conducting indoor multi-sequence local loading tests on core samples from asphalt pavement wheel track zones and shoulders to obtain the strain rate values of the material under multiple stresses. First, the strain rate values at the performance start point and performance inflection point throughout the material's service life are determined. Then, assuming the pavement age corresponding to the performance inflection point, the performance development law is determined by a two-stage fitting of the material's strain rate under different pavement ages and stresses. The pavement age value at the performance inflection point is determined based on the closest values of the left and right derivative functions at the pavement age, ultimately obtaining the segmented performance development law of the material's strain rate. This embodiment of the method can comprehensively and effectively determine the strain rate development law of actual asphalt pavements based on their traffic characteristics, helping pavement management units to formulate scientific and refined maintenance strategies for pavement rutting and saving maintenance costs.
[0060] The following uses the results of multi-sequence local loading tests on core samples from the wheel track zone and shoulder of the Lianyungang-Xuzhou Expressway as an example, combined with the accompanying drawings and specific embodiments, to further illustrate the present invention.
[0061] This embodiment provides a method for determining the variation law of strain rate of asphalt pavement material with road age, specifically including the following steps:
[0062] Step 1: Core samples of the surface layer taken from the wheel track area and shoulder of the Lianyungang-Xuzhou Expressway were cut according to layer thickness. After cutting, mid-layer specimens were selected for multi-sequence local loading tests. The specimen thickness was 54–60 mm, and the diameter was 150 mm. The loading stress sequence was set according to the stress characteristics of the mid-layer as follows: Figure 1 As shown in the figure. A half-sine wave pulse load was used in the experiment. A complete loading cycle consisted of a 0.1s loading time and a 0.9s unloading time. The preload stress was 0.6MPa, and the loading was repeated 400 times. The stress levels for the remaining sequences were 0.7MPa, 1.0MPa, and 1.2MPa, with each sequence repeated 50 times. The test temperature was 58℃, and the indenter diameter was 50mm.
[0063] Step 2: Based on the cumulative permanent strain curve obtained from the above experiments, see... Figure 2 The slopes of the cumulative strain of the material over time were fitted for loading sequences 1, 2, and 3, respectively. The fitting results are shown in Table 1.
[0064] Table 1. Strain rates of materials under different stress levels (unit: με / s)
[0065]
[0066] Step 3: Calculate the ratio of the strain rate of the wheel track to the strain rate of the shoulder under different stress levels, denoted as A. According to Table 2, the value of A increases with increasing stress level, which meets the requirements.
[0067] Table 2. Strain rate ratio between wheel track area and road shoulder.
[0068]
[0069] Step 4: Consulting the PMS system of the Lianyungang-Xuzhou Expressway, we find that the road section where the core was taken was 14 years old. Therefore, we obtain three points: A, B, and C, corresponding to the first year of operation, the k-th year (corresponding to the minimum strain rate), and the 14th year, as shown in Table 3. Since the minimum strain rate of the material under different stress levels may not be obtained in the same year, the years in which the minimum strain rate was obtained under the three stress levels are represented by k1, k2, and k3, respectively. The minimum strain rate under the three stress levels is taken as follows: The calculation results are shown in Table 3.
[0070] Table 3. Characteristic points of material strain rate under different stress levels.
[0071] stress sequence A B C 0.7MPa (1,15.8) <![CDATA[(k1,6.3)]]> (14,19.5) 1.0MPa (1,35.2) <![CDATA[(k2,14.1)]]> (14,48.7) 1.2MPa (1,41.6) <![CDATA[(k3,16.6)]]> (14,68.1)
[0072] Step 5: Let x = 2, 3, 4…13. Taking A (corresponding to 0.7 MPa) as the starting point and B as the ending point, fit 12 power functions, denoted as f1, f2, f3…f12 respectively. The fitting results are shown in… Figure 3 Similarly, the power function fitting results for 1.0 MPa and 1.2 MPa are shown in the following figures. Figure 4 and Figure 5 .
[0073] Step 6: Let x = 2, 3, 4…13. Taking B (corresponding to 0.7 MPa) as the starting point and C as the ending point, fit 12 exponential functions, denoted as g1, g2, g3…g12 respectively. The fitting results are shown in… Figure 6 Similarly, the exponential function fitting results for 1.0 MPa and 1.2 MPa are shown in the figures below. Figure 7 and Figure 8 .
[0074] Step 7: Fit the f values obtained under different stresses respectively. j (x) and g j Differentiating (x) yields the derivative function f′. j (x) and g′ j (x), j = 1, 2, 3…12, the original function and derivative function are shown in Tables 4 to 6.
[0075] Table 4. Power functions and exponential functions fitted to 0.7 MPa and their derivatives.
[0076] j AB AB' BC BC' 1 f1 = 15.8x^-1.322 f1' = -20.888x^-2.322 g1 = 5.238e^0.0939x g1' = 0.4918e^0.0939x 2 f2 = 15.8x^-0.834 f2' = -13.177x^-1.834 g² = 4.648e^0.1024x g2' = 0.476e^0.1024x 3 f3 = 15.8x^-0.661 f3' = -10.444x^-1.661 g3 = 4.0271e^0.1127x g3' = 0.4539e^0.1127x 4 f4 = 15.8x - 0.569 f4' = -8.99x^-1.569 g4 = 3.3797e^0.1252x g4' = 0.4231e^0.1252x 5 f5 = 15.8x^-0.511 f5' = -8.074x^-1.511 g5 = 2.7147e^0.1408x g5' = 0.3822e^0.1408x 6 f6 = 15.8x - 0.471 f6' = -7.442x^-1.471 g6 = 2.0483e^0.161x g6' = 0.3298e^0.161x 7 f7 = 15.8x^-0.441 f7' = -6.968x^-1.441 g7 = 1.407e^0.1878x g7' = 0.2642e^0.1878x 8 f8 = 15.8x - 0.417 f8' = -6.589x^-1.417 g8 = 0.8317e^0.2253x g8' = 0.1874e^0.2253x 9 f9 = 15.8x^-0.398 f9' = -6.288x^-1.398 g9 = 0.3779e^0.2817x g9' = 0.1065e^0.2817x 10 f10 = 15.8x^-0.382 f10' = -6.036x^-1.382 g10 = 0.1015e^0.3756x g10' = 0.0381e^0.3756x 11 f11 = 15.8x^-0.369 f11' = -5.83x^-1.369 g11 = 0.0073e^0.5633x g11'=0.0041e^0.5633x 12 f12 = 15.8x^-0.357 f12' = -5.64x^-1.357 g12 = 3E - 6e^1.1267x g12' = 3.38E-6e^1.1267x
[0077] Table 5. Power functions and exponential functions fitted to 1.0 MPa and their derivatives.
[0078] j AB AB' BC BC' 1 f1 = 35.2x^-1.322 f1' = -46.5344x^-2.322 g1 = 11.449e^0.1034x g1' = 1.1838e^0.1034x 2 f2 = 35.2x^-0.834 f2' = -29.3568x^-1.834 g2 = 10.037e^0.1128x g2' = 1.1322e^0.1128x 3 f3 = 35.2x^-0.661 f3' = -23.2672x^-1.661 g3 = 8.571e^0.1241x g3' = 1.0637e^0.1241x 4 f4 = 35.2x^-0.569 f4' = -20.0288x^-1.569 g4 = 7.0664e^0.1379x g4' = 0.9744e^0.1379x 5 f5 = 35.2x^-0.511 f5' = -17.9872x^-1.511 g5 = 5.5515e^0.1551x g5' = 0.861e^0.1551x 6 f6 = 35.2x^-0.471 f6' = -16.5792x^-1.471 g6 = 4.0708e^0.1773x g6' = 0.7217e^0.1773x 7 f7 = 35.2x^-0.441 f7' = -15.5232x^-1.441 g7 = 2.6917e^0.2068x g7' = 0.5566e^0.2068x 8 f8 = 35.2x^-0.417 f8' = -14.6784x^-1.417 g8 = 1.5085e^0.2482x g8' = 0.3744e^0.2482x 9 f9 = 35.2x^-0.398 f9' = -14.0096x^-1.398 g9 = 0.6328e^0.3102x g9' = 0.1963e^0.3102x 10 f10 = 35.2x^-0.382 f10' = -13.4464x^-1.382 g10 = 0.1488e^0.4136x g10' = 0.0615e^0.4136x 11 f11 = 35.2x^-0.369 f11' = -12.9888x^-1.369 g11 = 0.0082e^0.6205x g11' = 0.0051e^0.6205x 12 f12 = 35.2x^-0.357 f12' = -12.5664x^-1.357 g12 = 1E-6e^1.2409x g12' = 1.2409E-6e^1.2409x
[0079] Table 6. Power functions and exponential functions fitted to 1.2 MPa and their derivatives
[0080]
[0081]
[0082] Step 8: Define D(x) = |f′ j (x)|-|g′ j Calculate the value of D(x) when x = 2, 3, 4…13. The values of D(x) corresponding to different x values under the three stress conditions are shown in Tables 7 to 9.
[0083] Table 7. D(x) and its values at 0.7 MPa
[0084] <![CDATA[D(x)=|f′ j (x)|-|g′ j (x)|]]> x Value of D(x) D1 = 20.888x^-2.322 - 0.4918e^0.0939x 2 3.58 D2 = 13.177x^-1.834 - 0.476e^0.1024x 3 1.11 D3 = 10.444x^-1.661 - 0.4539e^0.1127x 4 0.33 D4 = 8.99x^-1.569 - 0.4231e^0.1252x 5 -0.07 D5 = 8.074x^-1.511 - 0.3822e^0.1408x 6 -0.35 D6 = 7.442x^-1.471 - 0.3298e^0.161x 7 -0.59 D7 = 6.968x^-1.441 - 0.2642e^0.1878x 8 -0.84 D8 = 6.589x^-1.417 - 0.1874e^0.2253x 9 -1.13 D9 = 6.288x^-1.398 - 0.1065e^0.2817x 10 -1.53 D10 = 5.83x^-1.369 - 0.0381e^0.3756x 11 -2.15 D11 = 5.83x^-1.369 - 0.0041e^0.5633x 12 -3.34 D12 = 5.64x^-1.357 - 3.38E-6e^1.1267x 13 -7.59
[0085] Table 8. D(x) and its values at 1.0 MPa
[0086] <![CDATA[D(x)=|f′ j (x)|-|g′ j (x)|]]> x Value range of D(x) D1 = 46.5344x^-2.322 - 1.1838e^0.1034x 2 7.85 D2 = 29.3568x^-1.834 - 1.1322e^0.1128x 3 2.33 D3 = 23.2672x^-1.661 - 1.0637e^0.1241x 4 0.58 D4 = 20.0288x^-1.569 - 0.9744e^0.1379x 5 -0.34 D5 = 17.9872x^-1.511 - 0.861e^0.1551x 6 -0.98 D6 = 16.5792x^-1.471 - 0.7217e^0.1773x 7 -1.55 D7 = 15.5232x^-1.441 - 0.5566e^0.2068x 8 -2.14 D8 = 14.6784x^-1.417 - 0.3744e^0.2482x 9 -2.84 D9 = 14.0096x^-1.398 - 0.1963e^0.3102x 10 -3.81 D10 = 13.4464x^-1.382 - 0.0615e^0.4136x 11 -5.33 D11 = 12.9888x^-1.369 - 0.0051e^0.6205x 12 -8.30 D12 = 12.5664x^-1.357 - 1.2409E-6e^1.2409x 13 -12.19
[0087] Table 9. D(x) and its values at 1.2 MPa
[0088]
[0089]
[0090] Step 9: As shown in Tables 7 to 9, under stresses of 0.7 MPa, 1.0 MPa, and 1.2 MPa, |D(x)| reaches its minimum value in the 5th, 5th, and 4th years, respectively. That is, under the three stress conditions, the strain rate of the pavement material reaches its minimum value during the entire service life when k1 = 5, k2 = 5, and k3 = 4, respectively. This point is also the turning point of the strain rate. Thus, a set of segmented variation laws of pavement material strain rate with road age is uniquely determined, as shown in Table 10.
[0091] Table 10. Stage-wise variation of strain rate of materials under different stress conditions.
[0092]
[0093] In summary, this embodiment provides a method for determining the strain rate variation law of asphalt pavement materials with road age. First, the strain rate result of the core sample at the same location as the core sample taken from the wheel track strip is used as the starting point for the strain rate development law of this road section, and the range of the minimum strain rate value is determined. This solves the drawback of traditional performance evaluation that cannot anchor the performance starting point and performance transition point, making it possible to transform qualitative evaluation into quantitative evaluation. Second, due to the use of innovative high-temperature performance evaluation tests, the multi-dimensional strain rate development law of the material under different traffic axle loads can be obtained, thus making the evaluation results more comprehensive, complete, and reliable.
[0094] This embodiment also provides a device for determining the variation law of strain rate of asphalt pavement material with road age, including:
[0095] At least one processor;
[0096] At least one memory for storing at least one program;
[0097] When the at least one program is executed by the at least one processor, the at least one processor performs the method as described above.
[0098] This embodiment provides a device for determining the variation law of strain rate of asphalt pavement material with road age. It can execute the method for determining the variation law of strain rate of asphalt pavement material with road age provided in the method embodiment of the present invention. It can execute any combination of implementation steps of the method embodiment and has the corresponding functions and beneficial effects of the method.
[0099] This embodiment also provides a storage medium storing instructions or programs that can execute the method for determining the variation law of strain rate of asphalt pavement material with road age provided in the method embodiment of the present invention. When the instructions or programs are run, any combination of implementation steps of the method embodiment can be executed, and the method has the corresponding functions and beneficial effects.
[0100] In some alternative embodiments, the functions / operations mentioned in the block diagrams may not occur in the order shown in the operation diagrams. For example, depending on the functions / operations involved, two consecutively shown blocks may actually be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order. Furthermore, the embodiments presented and described in the flowcharts of this invention are provided by way of example to provide a more comprehensive understanding of the technology. The disclosed methods are not limited to the operations and logic flows presented herein. Alternative embodiments are contemplated in which the order of various operations is altered and sub-operations described as part of a larger operation are executed independently.
[0101] Furthermore, although the invention has been described in the context of functional modules, it should be understood that, unless otherwise stated, one or more of the described functions and / or features may be integrated into a single physical device and / or software module, or one or more functions and / or features may be implemented in a separate physical device or software module. It is also understood that a detailed discussion of the actual implementation of each module is unnecessary for understanding the invention. Rather, given the properties, functions, and internal relationships of the various functional modules in the apparatus disclosed herein, the actual implementation of the module will be understood within the scope of conventional skill of an engineer. Therefore, those skilled in the art can implement the invention as set forth in the claims using ordinary techniques without excessive experimentation. It is also understood that the specific concepts disclosed are merely illustrative and not intended to limit the scope of the invention, which is determined by the full scope of the appended claims and their equivalents.
[0102] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, essentially, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.
[0103] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device.
[0104] More specific examples of computer-readable media (a non-exhaustive list) include: electrical connections (electronic devices) having one or more wires, portable computer disk drives (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Furthermore, computer-readable media can even be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in computer memory.
[0105] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.
[0106] In the foregoing description of this specification, references to terms such as "one embodiment," "another embodiment," or "some embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0107] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.
[0108] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the above embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.
Claims
1. A method for determining the variation law of strain rate of asphalt pavement material with road age, characterized in that, Includes the following steps: S1. Conduct multi-sequence local loading tests on pavement core specimens; S2. Based on the cumulative strain curve obtained from the experiment, fit the slope of the cumulative strain changing with time, and use it as the strain rate. ; S3. Calculate the ratio of the wheel track strain rate to the shoulder strain rate under different stress levels, denoted as R; S4. Set three points A(1, ..., ...) respectively. ), B(k, ), C(n, ), where point A (1, () represents the strain rate of the pavement material in the first year after the road opens to traffic. Point B(k, This represents the point at which the material strain rate reaches its minimum in the kth year after the line opens to traffic. Point C(n, The number represents the strain rate of the material in the year the core was taken, i.e., when the road age is n. ; S5. Suppose that the possible values of k are x = 2, 3, 4...n-1. For each x, let point A(1, ..., n-1) be the starting point of the k-value pair. Starting from the assumed turning point (x, ...) Using as the endpoint, a power function is obtained by fitting, denoted as . ,in For road age, 1 < t ≤ x; S6. For each identical x, with the assumed inflection point (x, Starting from point C(n, ...) and taking point C(n, ...) as the starting point, ... Using as the endpoint, an exponential function is obtained by fitting, denoted as . ,in For road age, x ≤ t ≤ n; S7. For the functions respectively and By taking the derivative, we can obtain the derivative function. and ; S8, Definition Calculate the values when x = 2, 3, 4, ..., n-1. The value of ; S9, Confirm The value of x at which the minimum value is taken is the road age k at the actual performance inflection point; thus, the strain rate of the pavement material is uniquely determined. As the road age The phased change pattern is as follows: when 1 < t ≤ k, = When t ≥ k, = .
2. The method for determining the variation law of strain rate of asphalt pavement material with road age according to claim 1, characterized in that, The road surface core samples in step S1 include core samples from the wheel track area and the shoulder area, and the core samples from the wheel track area and the shoulder area are taken from the same traffic section of the same highway.
3. The method for determining the variation law of strain rate of asphalt pavement material with road age according to claim 1, characterized in that, Step S1 includes: The road surface core sample was divided into upper, middle and lower layers, and then a multi-sequence local loading test was performed on the sample of each layer.
4. The method for determining the variation law of strain rate of asphalt pavement material with road age according to claim 3, characterized in that, The test temperatures of specimens at different layers are maintained at a preset temperature difference; The test temperature range for the top layer is 60~65℃, for the middle layer it is 55~60℃, and for the bottom layer it is 50~55℃.
5. The method for determining the variation law of strain rate of asphalt pavement material with road age according to claim 1, characterized in that, The multi-sequence local loading described in step S1 includes two loading stages: preloading and multi-stress loading. The preloading stage sets only one stress level and a fixed number of repeated loading sequences, while the multi-stress loading stage sets at least three different stress magnitudes but with the same number of repeated loading sequences.
6. The method for determining the variation law of strain rate of asphalt pavement material with road age according to claim 3, characterized in that, In step S1, the parameter settings for the loading schemes of the same layer shoulder and wheel track core samples in the multi-sequence local loading test are consistent.
7. The method for determining the variation law of strain rate of asphalt pavement material with road age according to claim 1, characterized in that, In step S3, the value of R increases with the increase of stress level.
8. The method for determining the variation law of strain rate of asphalt pavement material with road age according to claim 1, characterized in that, In step S4 The strain rate value is taken for the core sample at the wheel track. The strain rate value is taken for the core sample at the road shoulder.
9. The method for determining the variation law of strain rate of asphalt pavement material with road age according to claim 1, characterized in that, The minimum material strain rate within N years of the line opening in step S4. The value range is [0.2*]. 0.5* ]between.
10. A device for determining the variation law of strain rate of asphalt pavement material with road age, characterized in that, include: At least one processor; At least one memory for storing at least one program; When the at least one program is executed by the at least one processor, the at least one processor implements the method of any one of claims 1-9.