A method for judging the remaining life of asphalt pavement based on material testing

Abstract

The present application relates to the field of road engineering technology, and discloses a method for determining the remaining life of an asphalt pavement based on material testing. The method first takes a core from a target asphalt pavement to obtain a test specimen, and then performs an indirect tensile fatigue test on the surface layer of the test specimen to determine the remaining fatigue life of the surface layer of the target asphalt pavement, performs a local loading test on the surface layer of the test specimen to determine the remaining rutting life of the surface layer of the target asphalt pavement, and performs an indirect tensile fatigue test on the base layer of the test specimen to determine the remaining fatigue life of the base layer of the target asphalt pavement. Based on material testing, the present application determines the remaining life of an asphalt pavement through three material tests, targeting the main requirements of the surface layer for fatigue resistance and rutting resistance, and the main requirement of the base layer for fatigue resistance.

Description

Technical Field

[0001] The present application relates to the field of road engineering technology, and in particular to a method for determining the remaining life of an asphalt pavement based on material testing. Background Art

[0002] With the rapid development of economic construction, the construction of high-grade highways is also changing with each passing day. Asphalt pavement is widely used due to its advantages such as high driving comfort, convenient maintenance and repair, and fast traffic speed. Asphalt pavement accounts for more than 90% of the total mileage of highways and plays a vital role in the highway transportation network.

[0003] Different layers of asphalt pavement require different functions from materials. When evaluating old roads, a very important step is to evaluate whether the materials in a certain layer meet the corresponding functional requirements. At present, for semi-rigid base asphalt pavement, the main requirements for the surface layer are fatigue resistance and rutting resistance, and the main requirement for the base layer is fatigue resistance. However, there is still a lack of evaluation methods for the remaining life of pavement based on different material properties, and it is impossible to clarify the remaining life of asphalt pavement. Summary of the invention

[0004] The present application discloses a method for determining the remaining life of an asphalt pavement based on material testing, in order to solve the technical problem in the prior art that there is a lack of an evaluation method for the remaining life of a pavement based on different material properties and the remaining life of an asphalt pavement cannot be determined clearly.

[0005] The present application discloses a method for determining the remaining life of an asphalt pavement based on material testing, comprising:

[0006] Take cores from the target asphalt pavement to obtain test specimens;

[0007] Performing an indirect tensile fatigue test on the surface layer of the test specimen to determine the fatigue life of the surface layer of the target asphalt pavement, wherein the indirect tensile fatigue test on the surface layer of the test specimen is used to determine the fatigue life of the surface layer of the test specimen and determine the fatigue life of the surface layer of the target asphalt pavement;

[0008] Performing a local loading test on the surface layer of the test specimen to determine the remaining life of the surface layer of the target asphalt pavement against rutting, wherein the local loading test on the surface layer of the test specimen is used to determine the flow number of the surface layer material of the test specimen and the required flow number of the surface layer material, and determine the remaining life of the surface layer of the target asphalt pavement against rutting;

[0009] An indirect tensile fatigue test is performed on the base layer of the test specimen to determine the remaining fatigue life of the base layer of the target asphalt pavement, wherein the indirect tensile fatigue test is performed on the base layer of the test specimen to determine the predicted fatigue cracking life of the base layer of the test specimen and the cumulative equivalent axle times of permanent deformation of the base layer during the prediction period, and determine the remaining fatigue life of the base layer of the target asphalt pavement.

[0010] Optionally, the indirect tensile fatigue test is performed on the surface layer of the test specimen to determine the fatigue resistance remaining life of the surface layer of the target asphalt pavement, including:

[0011] Determining the fatigue life of the surface layer based on the test specimen;

[0012] According to the surface layer fatigue life and the preset new asphalt pavement surface layer fatigue life, the surface layer fatigue resistance remaining life of the target asphalt pavement is determined.

[0013] Optionally, the local loading test is performed on the surface layer of the test specimen to determine the remaining life of the surface layer of the target asphalt pavement against rutting, including:

[0014] Obtain the number of traffic volumes on the road surface over the years, and determine the cumulative equivalent axle times of permanent deformation of the surface layer within the prediction period based on the number of traffic volumes on the road surface over the years;

[0015] Determine the vertical compressive stress at the top of each layer of the surface layer and the permanent deformation of the surface layer according to the test specimen;

[0016] Using the highway rutting depth control standard and according to the permanent deformation of the surface layer, determining the allowable permanent deformation of the surface layer;

[0017] Determine the rutting deformation depth of the surface layer according to the accumulated equivalent axle times of permanent deformation of the surface layer during the prediction period, the vertical compressive stress at the top of each layer of the surface layer and the allowable permanent deformation of the surface layer;

[0018] Determining the required flow number of the surface material according to the rutting deformation depth of the surface layer;

[0019] The flow number of the surface material is determined based on the test specimen, and the remaining life of the surface layer rutting resistance of the target asphalt pavement is determined based on the flow number of the surface material and the required flow number of the surface material.

[0020] Optionally, the determining of the accumulated equivalent axle times of permanent deformation of the surface layer within the prediction period according to the amount of traffic volume of the road surface over the years includes:

[0021] According to the traffic volume of the road surface over the years, determine the daily average equivalent axle times of permanent deformation of the surface layer and the growth rate in the first year;

[0022] The cumulative equivalent axle-count of permanent deformation of the surface layer during the forecast period is determined based on the average daily equivalent axle-count of permanent deformation of the surface layer and the first annual growth rate.

[0023] Optionally, determining the vertical compressive stress at the top of each layer of the surface layer according to the test specimen includes:

[0024] According to the test specimens, a mechanical response analysis of the pavement structure is performed based on an elastic layered system to determine the vertical compressive stress at the top of each layer of the surface layer.

[0025] Optionally, determining the rutting deformation depth of the surface layer according to the accumulated equivalent axle times of permanent deformation of the surface layer during the prediction period, the vertical compressive stress at the top of each layer of the surface layer, and the allowable permanent deformation of the surface layer includes:

[0026] Determine the allowable permanent deformation of each layer of the surface layer according to the accumulated equivalent axial order of permanent deformation of the surface layer during the forecast period, the vertical compressive stress at the top of each layer of the surface layer and the allowable permanent deformation of the surface layer;

[0027] The rutting deformation depth of the surface layer is determined according to the accumulated equivalent axle times of permanent deformation of the surface layer during the prediction period, the vertical compressive stress at the top of each layer of the surface layer and the allowable permanent deformation of each layer of the surface layer.

[0028] Optionally, the indirect tensile fatigue test is performed on the base of the test specimen to determine the fatigue resistance remaining life of the base of the target asphalt pavement, including:

[0029] Determining the tensile stress at the bottom of the base layer according to the test specimen;

[0030] Performing a splitting fatigue test on the test specimen to determine a first regression parameter of the fatigue test and a second regression parameter of the fatigue test;

[0031] Determine the predicted fatigue cracking life of the base layer according to the base layer bottom tensile stress, the fatigue test first regression parameter and the fatigue test second regression parameter;

[0032] Obtain the number of traffic volumes of the road surface over the years, and determine the cumulative equivalent axle times of permanent deformation of the base layer during the prediction period based on the number of traffic volumes of the road surface over the years;

[0033] The remaining fatigue life of the base layer of the target asphalt pavement is determined based on the predicted fatigue cracking life of the base layer and the accumulated equivalent axle times of permanent deformation of the base layer during the prediction period.

[0034] Optionally, the step of determining the cumulative equivalent axle times of permanent deformation of the base layer within the prediction period according to the amount of traffic volume on the road surface over the years includes:

[0035] Determine the daily average equivalent axle load of fatigue cracking of the base layer and the second annual growth rate based on the traffic volume of the road surface over the years;

[0036] The cumulative equivalent axle times of permanent deformation of the base layer during the forecast period is determined based on the average daily equivalent axle times of fatigue cracking of the base layer and the second annual growth rate.

[0037] Optionally, determining the base layer bottom tensile stress according to the test specimen includes:

[0038] According to the test specimens, a mechanical response analysis of the pavement structure is performed based on an elastic layered system to determine the tensile stress at the bottom of the base layer.

[0039] The present application relates to the field of road engineering technology, and discloses a method for determining the remaining life of an asphalt pavement based on material testing. The method first takes a core from a target asphalt pavement to obtain a test specimen, and then performs an indirect tensile fatigue test on the surface layer of the test specimen to determine the remaining fatigue life of the surface layer of the target asphalt pavement, performs a local loading test on the surface layer of the test specimen to determine the remaining rutting life of the surface layer of the target asphalt pavement, and performs an indirect tensile fatigue test on the base layer of the test specimen to determine the remaining fatigue life of the base layer of the target asphalt pavement. Based on material testing, the present application determines the remaining life of an asphalt pavement through three material tests, targeting the main requirements of the surface layer for fatigue resistance and rutting resistance, and the main requirement of the base layer for fatigue resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solution of the present application, the drawings required for use in the embodiments are briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0041] Figure 1 A schematic diagram of the workflow of a method for determining the remaining life of an asphalt pavement based on material testing disclosed in an embodiment of the present application;

[0042] Figure 2 A fatigue life analysis diagram of the surface layer in an example of a method for determining the remaining life of an asphalt pavement based on material testing disclosed in an embodiment of the present application; DETAILED DESCRIPTION

[0043] In order to solve the technical problem in the prior art that there is a lack of an evaluation method for the remaining life of a pavement based on different material properties and that the remaining life of an asphalt pavement cannot be clearly determined, the present application discloses a method for determining the remaining life of an asphalt pavement based on material testing through the following embodiments.

[0044] The present application discloses a method for determining the remaining life of an asphalt pavement based on material testing, see Figure 1 As shown in the schematic diagram of the work flow, the method for determining the remaining life of an asphalt pavement based on material testing includes:

[0045] Step S101, coring the target asphalt pavement to obtain a test specimen.

[0046] Step S102, performing an indirect tensile fatigue test on the surface layer of the test specimen to determine the remaining life of the surface layer fatigue resistance of the target asphalt pavement, wherein the indirect tensile fatigue test on the surface layer of the test specimen is used to determine the fatigue life of the surface layer of the test specimen and determine the remaining life of the surface layer fatigue resistance of the target asphalt pavement.

[0047] In some embodiments of the present application, the indirect tensile fatigue test is performed on the surface layer of the test specimen to determine the fatigue resistance remaining life of the surface layer of the target asphalt pavement, including:

[0048] Based on the test specimen, the fatigue life of the surface layer is determined.

[0049] According to the surface layer fatigue life and the preset new asphalt pavement surface layer fatigue life, the surface layer fatigue resistance remaining life of the target asphalt pavement is determined.

[0050] Specifically, the surface fatigue life N 老路面层 , determined by indirect tensile fatigue test method. Fatigue life of newly built asphalt pavement surface layer N f1 Determined by the following formula:

[0051] lgN f1 =4.7962-2.4076lgσ;

[0052] Here, σ represents the stress level, which is determined in advance based on the actual application scenario.

[0053] The remaining fatigue life of the surface layer is determined by the following formula:

[0054] Surface layer fatigue residual life = N 老路面层 / N f1 *100%;

[0055] Step S103, performing a local loading test on the surface layer of the test specimen to determine the remaining life of the surface layer of the target asphalt pavement against rutting, wherein the local loading test on the surface layer of the test specimen is used to determine the flow number of the surface layer material of the test specimen and the required flow number of the surface layer material, and determine the remaining life of the surface layer against rutting of the target asphalt pavement.

[0056] Specifically, the asphalt layer permanent deformation prediction model is used to calculate the cumulative equivalent axial order Ne of the permanent deformation of the surface layer during the prediction period, the vertical compressive stress P of the top of each layer of the surface layer, and the vertical compressive stress P of the top of each layer of the surface layer. i And the allowable permanent deformation R of each layer of the surface layer ai By using this into the calculation, we can get the rutting deformation depth RD of the surface layer, and then we can calculate the required flow number F of the surface material. n , that is, the control standard of the surface material is obtained.

[0057] Among them, the rutting deformation depth RD of the surface layer is related to the required flow number F of the surface material. n The relationship between them is as follows:

[0058] F n =1705.2RD -1.038 ;

[0059] In some embodiments of the present application, the local loading test is performed on the surface layer of the test specimen to determine the remaining life of the surface layer of the target asphalt pavement against rutting, including:

[0060] Obtain the annual traffic volume of the road surface, and determine the cumulative equivalent axle times of permanent deformation of the surface layer during the prediction period based on the annual traffic volume of the road surface.

[0061] Based on the test specimens, the vertical compressive stress at the top of each layer of the surface layer is determined, as well as the permanent deformation of the surface layer.

[0062] The allowable permanent deformation of the surface layer is determined by utilizing the highway rutting depth control standard and according to the permanent deformation of the surface layer.

[0063] The rutting deformation depth of the surface layer is determined according to the accumulated equivalent axle times of permanent deformation of the surface layer during the prediction period, the vertical compressive stress at the top of each layer of the surface layer and the allowable permanent deformation of the surface layer.

[0064] The required flow number of the surface layer material is determined according to the rutting deformation depth of the surface layer.

[0065] The flow number of the surface material is determined based on the test specimen, and the remaining life of the surface layer rutting resistance of the target asphalt pavement is determined based on the flow number of the surface material and the required flow number of the surface material.

[0066] In some embodiments of the present application, determining the accumulated equivalent axle times of permanent deformation of the surface layer within the prediction period according to the amount of traffic volume of the road surface over the years includes:

[0067] Based on the traffic volume of the road surface over the years, determine the average daily equivalent axle times and the first year growth rate of permanent deformation of the surface layer.

[0068] The cumulative equivalent axle-count of permanent deformation of the surface layer during the forecast period is determined based on the average daily equivalent axle-count of permanent deformation of the surface layer and the first annual growth rate.

[0069] Specifically, combined with the traffic volume of the road surface over the years, the daily average equivalent axle number N of permanent deformation of the surface layer can be determined. 1 and annual growth rateγ 1 Based on the traffic load parameter analysis in Appendix A of Highway Asphalt Pavement Design Specifications JTG D50-2017, the cumulative equivalent axle times Ne during the forecast period can be obtained as follows:

[0070]

[0071] In some embodiments of the present application, determining the vertical compressive stress of the top of each layer of the surface layer according to the test specimen includes:

[0072] According to the test specimen, based on the elastic layered system, the mechanical response analysis of the pavement structure is carried out to determine the vertical compressive stress P at the top of each layer of the surface layer. i .

[0073] In some embodiments of the present application, the rutting deformation depth of the surface layer is determined according to the accumulated equivalent axle times of permanent deformation of the surface layer during the prediction period, the vertical compressive stress at the top of each layer of the surface layer, and the allowable permanent deformation of the surface layer, including:

[0074] The allowable permanent deformation of each layer of the surface layer is determined according to the accumulated equivalent axial order of permanent deformation of the surface layer during the prediction period, the vertical compressive stress at the top of each layer of the surface layer and the allowable permanent deformation of the surface layer.

[0075] The rutting deformation depth of the surface layer is determined according to the accumulated equivalent axle times of permanent deformation of the surface layer during the prediction period, the vertical compressive stress at the top of each layer of the surface layer and the allowable permanent deformation of each layer of the surface layer.

[0076] Specifically, through actual measurement, the permanent deformation RD of the current surface layer can be obtained. 实测 , according to the highway rutting depth RD 容许 The control standard is not greater than 15mm, and the difference is solved (ie RD 容许 —RD 实测 ) can be obtained, the allowable permanent deformation of the surface layer R a ; Under the premise that the materials of other layers are determined and the attenuation of their material properties is not considered, the allowable permanent deformation R of each layer of the surface layer can be obtained. ai The specific formula is as follows, which mainly adopts the permanent deformation prediction model of asphalt layer of asphalt pavement in the "Highway Asphalt Pavement Design Specification":

[0077]

[0078]

[0079] Among them, R a Indicates the allowable permanent deformation of the surface layer; R ai represents the allowable permanent deformation of the i-th layer of the surface layer; n represents the number of layers of the surface layer; T pef Indicates the equivalent temperature of permanent deformation of asphalt layer (℃), determined according to Appendix G of "Highway Asphalt Pavement Design Specification"; N e It represents the cumulative equivalent axle load of permanent deformation of the surface layer during the prediction period, more specifically, the cumulative number of equivalent axle load actions on the design lane within the design service life or the period from opening to the first rutting maintenance, determined according to Appendix A of the Highway Asphalt Pavement Design Code; h i Indicates the thickness of the surface layer i (mm); h 0 Indicates the thickness of the wheel rutting test specimen (mm); R 0i k represents the permanent deformation of the i-th layer asphalt mixture in the wheel rutting test when the test temperature is 60℃, the pressure is 0.7MPa, and the number of loading times is 2520 times; Ri Indicates the comprehensive correction coefficient. k Ri It means that the comprehensive correction coefficient is determined by the following formula:

[0080]

[0081]

[0082]

[0083] Among them, z i h represents the depth of the i-th layer of the surface layer (mm). The first layer is taken as 15mm, and the other layers are the depths of the road surface from the midpoint of the asphalt layer; a Indicates the surface thickness, surface thickness h a If it is greater than 200mm, take 200mm; p i It represents the vertical compressive stress P at the top of each layer of the surface layer i .

[0084] Step S104, performing an indirect tensile fatigue test on the base layer of the test specimen to determine the remaining fatigue life of the base layer of the target asphalt pavement, wherein the indirect tensile fatigue test on the base layer of the test specimen is used to determine the predicted fatigue cracking life of the base layer of the test specimen and the cumulative equivalent axle times of permanent deformation of the base layer during the prediction period, and determine the remaining fatigue life of the base layer of the target asphalt pavement.

[0085] Specifically, the predicted fatigue cracking life of the base layer Nf2 By comparing with the cumulative equivalent axle times Ne′ of the permanent deformation of the base during the prediction period, it can be determined whether the fatigue resistance of the current pavement base meets the requirements and further determine the remaining fatigue resistance life of the base.

[0086] In some embodiments of the present application, the indirect tensile fatigue test is performed on the base of the test specimen to determine the fatigue resistance remaining life of the base of the target asphalt pavement, including:

[0087] Based on the test specimen, the tensile stress at the bottom of the base layer is determined.

[0088] A splitting fatigue test is performed on the test specimen to determine a first regression parameter of the fatigue test and a second regression parameter of the fatigue test.

[0089] The predicted fatigue cracking life of the base layer is determined according to the base layer bottom tensile stress, the fatigue test first regression parameter and the fatigue test second regression parameter.

[0090] Obtain the number of traffic volumes on the road surface over the years, and determine the cumulative equivalent axle times of permanent deformation of the base layer during the prediction period based on the number of traffic volumes on the road surface over the years.

[0091] The remaining fatigue life of the base layer of the target asphalt pavement is determined based on the predicted fatigue cracking life of the base layer and the accumulated equivalent axle times of permanent deformation of the base layer during the prediction period.

[0092] Specifically, based on the splitting fatigue test and the inorganic binder fatigue equation, the first regression parameter a of the fatigue test and the second regression parameter b of the fatigue test are determined as follows:

[0093]

[0094] Among them, N 实 It represents the actual fatigue life of the base layer obtained in advance based on the test specimen in the splitting fatigue test, σ represents the stress level; S represents the flexural strength of the base material (MPa).

[0095] In some embodiments of the present application, determining the accumulated equivalent axle times of permanent deformation of the base layer within the prediction period according to the traffic volume of the road surface over the years includes:

[0096] Based on the traffic volume of the pavement over the years, the average daily equivalent axle load of fatigue cracking of the base layer and the second-year growth rate are determined.

[0097] The cumulative equivalent axle times of permanent deformation of the base layer during the forecast period is determined based on the average daily equivalent axle times of fatigue cracking of the base layer and the second annual growth rate.

[0098] Specifically, combined with the traffic volume of the road over the years, the daily average equivalent axle load N of fatigue cracking of the base layer can be determined. 1 ′ and the second year growth rate γ 2 , and based on the "Highway Asphalt Pavement Design Specifications", the cumulative equivalent axle times Ne' of the permanent deformation of the base during the prediction period can be obtained, and the formula is as follows:

[0099]

[0100] In some embodiments of the present application, determining the tensile stress at the bottom of the base layer according to the test specimen includes:

[0101] According to the test specimen, based on the elastic layered system, the mechanical response analysis of the pavement structure is carried out to determine the tensile stress σ at the bottom of the base layer. t .

[0102] Specifically, based on the "Highway Asphalt Pavement Design Specifications", a prediction model for the fatigue resistance remaining life of asphalt pavement base can be obtained:

[0103]

[0104] Among them, N f2 Indicates the remaining fatigue life of the base layer; k a represents the adjustment coefficient for seasonal frozen soil areas, which can be obtained by referring to the "Highway Asphalt Pavement Design Specification"; k T2 Represents the temperature adjustment coefficient, which is determined according to Appendix G of the Highway Asphalt Pavement Design Specifications; R s represents the flexural tensile strength of the base material (MPa); a represents the first regression parameter of the fatigue test; b represents the second regression parameter of the fatigue test; k c Indicates the comprehensive correction coefficient on site; σ t Indicates the tensile stress at the bottom of the base layer.

[0105] On-site comprehensive correction factor k c Determined by the following formula:

[0106]

[0107] Among them, c 1 、c 2 and c 3 Refer to "Highway Asphalt Pavement Design Specifications" for the following; h a and h b ——They are the surface layer thickness and the base layer thickness above the calculation point respectively.

[0108] The above embodiment of the present application discloses a method for determining the remaining life of an asphalt pavement based on material testing, which first involves coring the target asphalt pavement to obtain a test specimen, then performing an indirect tensile fatigue test on the surface layer of the test specimen to determine the remaining fatigue life of the surface layer of the target asphalt pavement, performing a local loading test on the surface layer of the test specimen to determine the remaining rutting life of the surface layer of the target asphalt pavement, and performing an indirect tensile fatigue test on the base layer of the test specimen to determine the remaining fatigue life of the base layer of the target asphalt pavement. Based on material testing, the present application determines the remaining life of an asphalt pavement through three material tests, targeting the main requirements of the surface layer for fatigue resistance and rutting resistance, and the main requirement of the base layer for fatigue resistance.

[0109] The above solution of this embodiment is explained below through an example.

[0110] The test specimens were obtained by core sampling from on-site cracks at K1724 and K1728 of Ninglian Expressway.

[0111] Remaining life of surface layer fatigue resistance:

[0112] At a stress level of 0.9 MPa, the fatigue life of the newly built asphalt pavement surface layer is about 80,000 times. According to the test specimen, the actual fatigue life of the surface layer of the test specimen is obtained as follows: Figure 2 As shown, the fatigue life of the surface layer is 3534 times, which is only 4.4% of that of conventional materials. This indicates that under the combined effects of the vehicle and the environment, the surface layer has been severely aged and its fatigue resistance has declined significantly. There is a high possibility that fatigue cracking or even fissures will occur in the surface layer in the future.

[0113] Remaining life of surface layer anti-rutting:

[0114] First, the cumulative equivalent axle load Ne of the permanent deformation of the surface layer during the prediction period is determined. The specific steps are as follows: Based on the calculation process of the axle load conversion coefficient in the "Highway Asphalt Pavement Design Specifications", the equivalent axle load conversion coefficients for different vehicle models when calculating the permanent deformation of the surface layer can be determined, as shown in Table 1:

[0115] Table 1

[0116] Small guest VIP Small goods Chinese goods Large goods Trailer Permanent deformation of the surface layer 0.0114 0.4142 0.0070 0.2435 1.2779 3.7832

[0117] The daily traffic volume of different models in different years and forecast years is converted into the equivalent standard axle load action times. Among them, small passenger cars and small trucks are not included in the standard axle load calculation, the lane coefficient is 0.55, and the direction coefficient is 0.5. The average daily equivalent axle times N of the permanent deformation of the surface layer of each model in different years are obtained. 1 , as shown in Table 2:

[0118] Table 2

[0119] years VIP Chinese goods Large goods Trailer total <![CDATA[N 1 (times / d)]]> 2013 71 448 3625 1052 5197 1429 2014 82 446 2773 2055 5356 1473 2015 87 545 2477 2547 5655 1555 2016 141 678 1397 4223 6439 1771 2017 83 303 2380 8012 10777 2964 2018 135 539 1224 8820 10719 2948 2019 154 559 985 13494 15193 4178 2020 175 580 793 20646 22195 6104 2021 199 602 638 31589 33029 9083 2022 227 625 514 48331 49696 13666 2023 258 648 413 73946 75266 20698 2024 294 673 333 113138 114437 31470 2025 334 698 268 173101 174401 47960 2026 380 724 216 264845 266164 73195

[0120] Based on the formula, when the permanent deformation of the surface layer reaches the allowable deformation value, the cumulative equivalent axle times Ne on the design lane within the design service life during the prediction period is shown in Table 3:

[0121] Table 3

[0122] years Remaining useful life Cumulative equivalent axle times Ne 2018 1 1075920 2019 2 2600917 2020 3 4828740 2021 4 8144026 2022 5 13132262 2023 6 20687113 2024 7 32173728 2025 8 49679212 2026 9 76395456

[0123] Based on the elastic layered system, considering the attenuation of pavement material performance, the mechanical response analysis of the pavement structure is carried out. After calculation, the vertical compressive stress P at the top of each layer of the surface layer can be obtained. i , as shown in Table 4:

[0124] Table 4

[0125]

[0126] According to actual measurements, the permanent deformation RD of the roadway on the rutting-intensive surface layer (K1724+400) is 实测 is 10.5mm. After difference calculation, the allowable permanent deformation of the surface layer R is obtained. a Based on this, the allowable permanent deformation R of each layer of the surface layer can be obtained: ai , as shown in Table 5:

[0127] Table 5

[0128]

[0129] Using the prediction model of permanent deformation of asphalt pavement asphalt layer, the cumulative equivalent axial deformation Ne of the surface layer during the above prediction period, the vertical compressive stress P of the top of each layer of the surface layer i And the allowable permanent deformation R of each layer of the surface layer ai By using the calculation, the rutting deformation depth RD of the structural layer material can be obtained, and then the corresponding flow number can be obtained, as shown in Table 6:

[0130] Table 6

[0131]

[0132] By analyzing the measured value of the flow number of the surface material and the required flow number of the surface material, it can be obtained that based on the current development law of traffic axles, the remaining life of the rutting surface material is 4 years, that is, by 2021, the rutting depth of the overall structure of this section will exceed 15mm.

[0133] Remaining fatigue life of base layer:

[0134] Based on the layered elastic system design method, Bisar3.0 software was used to analyze the mechanical response of the pavement structure, and the tensile stress at the bottom of the base layer was found to be 0.09434 MPa.

[0135] Based on the splitting fatigue test and the inorganic binder fatigue equation, the first regression parameter a and the second regression parameter b of the fatigue test are determined, as shown in Table 7:

[0136] Table 7

[0137] Grassroots a b Many blocks (1724+392) 9.7488 6.8927 Dense cracks (1728+156) 10.5340 5.7239

[0138] Then, each parameter is brought into the prediction model of the fatigue resistance remaining life of the asphalt pavement base, and the fatigue resistance remaining life N of the base is calculated. f2 , as shown in Table 8:

[0139] Table 8

[0140] Grassroots <![CDATA[Fatigue cracking life N f2 > Many blocks (1724+392) 5664413 Dense cracks (1728+156) 41410966

[0141] Combined with the traffic volume of the road over the years, the daily average equivalent axle load N of fatigue cracking of the base layer can be determined. 1 ′ and the second year growth rate γ 2 Based on the "Highway Asphalt Pavement Design Code", the cumulative equivalent axle times Ne′ of permanent deformation of the base during the prediction period can be obtained.

[0142] Among them, the cumulative equivalent axle load Ne′ of the permanent deformation of the base layer during the prediction period is determined by the following steps: Based on the calculation formula of the axle load conversion coefficient of the fatigue life of the base layer in the "Highway Asphalt Pavement Design Specifications", the equivalent axle load conversion coefficient of different vehicle models when calculating the fatigue cracking of the inorganic binder layer can be determined, as shown in Table 9:

[0143] Table 9

[0144] Model Small guest VIP Small goods Chinese goods Large goods Trailer Base fatigue cracking 0 0.0313 0 0.0083 1.0005 3.8059

[0145] The daily traffic volume of different models in different years and forecast years is converted into the number of equivalent standard axle load actions. Among them, small passenger cars and small trucks are not included in the standard axle load calculation, the lane coefficient is 0.55, and the direction coefficient is 0.5, as shown in Table 10:

[0146] Table 10

[0147]

[0148]

[0149] Based on the formula, it can be calculated that when the base layer is fatigue cracked, the cumulative equivalent axial deformation of the base layer during the prediction period is Ne′, as shown in Table 11:

[0150] Table 11

[0151] years Remaining useful life <![CDATA[Cumulative equivalent axle load repetitions N e (times / day) <!-- 10 -->]]> 2018 1 1047696 2019 2 2544585 2020 3 4745602 2021 4 8037355 2022 5 13008578 2023 6 20557794 2024 7 32057931 2025 8 49608107 2026 9 76418781

[0152] By comparing the predicted remaining fatigue life of the two base materials with the cumulative equivalent axle times of permanent deformation of the base during the prediction period, it can be obtained that: based on the current development law of traffic axle times, the remaining life of the base material with many block cracks is 2 years, that is, by 2020, the overall structure of the road section will experience fatigue cracking of the base; and the remaining life of the base material with dense cracks is 6 years, that is, by 2024, the overall structure of the road section will experience fatigue cracking of the base.

[0153] The present application is described in detail above in conjunction with specific implementation methods and exemplary examples, but these descriptions cannot be understood as limiting the present application. Those skilled in the art understand that, without departing from the spirit and scope of the present application, a variety of equivalent replacements, modifications or improvements can be made to the technical solution of the present application and its implementation methods, all of which fall within the scope of the present application. The scope of protection of the present application shall be subject to the attached claims.

Claims

1. A method for determining the remaining life of an asphalt pavement based on material testing, characterized in that: include: Take cores from the target asphalt pavement to obtain test specimens; Performing an indirect tensile fatigue test on the surface layer of the test specimen to determine the fatigue life of the surface layer of the target asphalt pavement, wherein the indirect tensile fatigue test on the surface layer of the test specimen is used to determine the fatigue life of the surface layer of the test specimen and determine the fatigue life of the surface layer of the target asphalt pavement; Performing a local loading test on the surface layer of the test specimen to determine the remaining life of the surface layer of the target asphalt pavement against rutting, wherein the local loading test on the surface layer of the test specimen is used to determine the flow number of the surface layer material of the test specimen and the required flow number of the surface layer material, and determine the remaining life of the surface layer of the target asphalt pavement against rutting; An indirect tensile fatigue test is performed on the base layer of the test specimen to determine the remaining fatigue life of the base layer of the target asphalt pavement, wherein the indirect tensile fatigue test is performed on the base layer of the test specimen to determine the predicted fatigue cracking life of the base layer of the test specimen and the cumulative equivalent axle times of permanent deformation of the base layer during the prediction period, and determine the remaining fatigue life of the base layer of the target asphalt pavement.

2. The method for determining the remaining life of an asphalt pavement based on material testing according to claim 1 is characterized in that: The indirect tensile fatigue test is performed on the surface layer of the test specimen to determine the fatigue resistance remaining life of the surface layer of the target asphalt pavement, including: Determining the fatigue life of the surface layer based on the test specimen; According to the surface layer fatigue life and the preset new asphalt pavement surface layer fatigue life, the surface layer fatigue resistance remaining life of the target asphalt pavement is determined.

3. The method for determining the remaining life of an asphalt pavement based on material testing according to claim 1 is characterized in that: The method of performing a local loading test on the surface layer of the test specimen to determine the remaining rutting resistance life of the surface layer of the target asphalt pavement includes: Obtain the number of traffic volumes on the road surface over the years, and determine the cumulative equivalent axle times of permanent deformation of the surface layer within the prediction period based on the number of traffic volumes on the road surface over the years; Determine the vertical compressive stress at the top of each layer of the surface layer and the permanent deformation of the surface layer according to the test specimen; Using the highway rutting depth control standard and according to the permanent deformation of the surface layer, determining the allowable permanent deformation of the surface layer; Determine the rutting deformation depth of the surface layer according to the accumulated equivalent axle times of permanent deformation of the surface layer during the prediction period, the vertical compressive stress at the top of each layer of the surface layer and the allowable permanent deformation of the surface layer; Determining the required flow number of the surface material according to the rutting deformation depth of the surface layer; The flow number of the surface material is determined based on the test specimen, and the remaining life of the surface layer rutting resistance of the target asphalt pavement is determined based on the flow number of the surface material and the required flow number of the surface material.

4. The method for determining the remaining life of an asphalt pavement based on material testing according to claim 3 is characterized in that: The method of determining the accumulated equivalent axle times of permanent deformation of the surface layer during the forecast period based on the traffic volume of the road surface over the years includes: According to the traffic volume of the road surface over the years, determine the daily average equivalent axle times of permanent deformation of the surface layer and the growth rate in the first year; The cumulative equivalent axle-count of permanent deformation of the surface layer during the forecast period is determined based on the average daily equivalent axle-count of permanent deformation of the surface layer and the first annual growth rate.

5. The method for determining the remaining life of an asphalt pavement based on material testing according to claim 3 is characterized in that: Determining the vertical compressive stress of each layer top of the surface layer according to the test specimen includes: According to the test specimens, a mechanical response analysis of the pavement structure is performed based on an elastic layered system to determine the vertical compressive stress at the top of each layer of the surface layer.

6. The method for determining the remaining life of an asphalt pavement based on material testing according to claim 3 is characterized in that: Determining the rutting deformation depth of the surface layer according to the accumulated equivalent axle times of permanent deformation of the surface layer during the prediction period, the vertical compressive stress of the top of each layer of the surface layer and the allowable permanent deformation of the surface layer includes: Determine the allowable permanent deformation of each layer of the surface layer according to the accumulated equivalent axial order of permanent deformation of the surface layer during the forecast period, the vertical compressive stress at the top of each layer of the surface layer and the allowable permanent deformation of the surface layer; The rutting deformation depth of the surface layer is determined according to the accumulated equivalent axle times of permanent deformation of the surface layer during the prediction period, the vertical compressive stress at the top of each layer of the surface layer and the allowable permanent deformation of each layer of the surface layer.

7. The method for determining the remaining life of an asphalt pavement based on material testing according to claim 1 is characterized in that: The indirect tensile fatigue test is performed on the base of the test specimen to determine the fatigue resistance remaining life of the base of the target asphalt pavement, including: Determining the tensile stress at the bottom of the base layer according to the test specimen; Performing a splitting fatigue test on the test specimen to determine a first regression parameter of the fatigue test and a second regression parameter of the fatigue test; Determine the predicted fatigue cracking life of the base layer according to the base layer bottom tensile stress, the fatigue test first regression parameter and the fatigue test second regression parameter; Obtain the number of traffic volumes of the road surface over the years, and determine the cumulative equivalent axle times of permanent deformation of the base layer during the prediction period based on the number of traffic volumes of the road surface over the years; The remaining fatigue life of the base layer of the target asphalt pavement is determined based on the predicted fatigue cracking life of the base layer and the accumulated equivalent axle times of permanent deformation of the base layer during the prediction period.

8. The method for determining the remaining life of an asphalt pavement based on material testing according to claim 7 is characterized in that: The cumulative equivalent axle times of permanent deformation of the base layer during the forecast period is determined based on the traffic volume of the road surface over the years, including: Determine the daily average equivalent axle load of fatigue cracking of the base layer and the second annual growth rate based on the traffic volume of the road surface over the years; The cumulative equivalent axle times of permanent deformation of the base layer during the forecast period is determined based on the average daily equivalent axle times of fatigue cracking of the base layer and the second annual growth rate.

9. The method for determining the remaining life of an asphalt pavement based on material testing according to claim 7 is characterized in that: Determining the tensile stress at the bottom of the base layer according to the test specimen comprises: According to the test specimens, a mechanical response analysis of the pavement structure is performed based on an elastic layered system to determine the tensile stress at the bottom of the base layer.

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