Model and Method for Determining the Dosage of Regenerator during In-situ Thermal Regeneration Repair of Asphalt Pavement

Abstract

The present invention relates to a model for determining the dosage of rejuvenator during in-situ hot recycling repair of asphalt pavement. When performing in-situ hot recycling repair of asphalt pavement, the present application can quickly determine the dosage of rejuvenator during in-situ hot recycling repair of the asphalt pavement to be repaired through the model for determining the dosage of rejuvenator during in-situ hot recycling repair of asphalt pavement. The 60°C dynamic viscosity data of asphalt in the model is obtained through the asphalt 60°C viscosity-temperature-asphalt mixture mixing viscosity resistance model, effectively solving the problem of time-consuming of traditional methods.

Description

Technical Field

[0001] The present invention relates to the technical field of road engineering, and particularly relates to a model method for determining the dosage of a rejuvenator during in-situ hot recycling repair of asphalt pavement. Background Art

[0002] For the service performance and service life of in-situ hot recycled asphalt mixture pavement, the key lies in whether the old asphalt can be effectively recycled. Generally, the old asphalt is recycled by adding a rejuvenator and its 60°C viscosity reaches the target grade. At present, in actual engineering, the common method is to determine the dosage of the rejuvenator by controlling three main indicators of the recycled asphalt according to the target grade of the recycled asphalt. For example, the trial mixing method can be used for the old asphalt recycling test: the rejuvenator is incorporated into the old asphalt according to an arithmetic progression ratio at a certain interval, the three main indicators of the recycled asphalt are measured, and a change curve is plotted. Then, the dosage of the rejuvenator is preliminarily determined by interpolation method. However, there are some problems with this method. First, it is difficult to obtain data, which requires a large amount of manpower and time. Second, the amount of data is small and not representative. It is inaccurate to rely on limited data points to represent the situation of the entire road section. Finally, once the dosage of the rejuvenator is determined, it is impossible to adjust the dosage of the rejuvenator according to the real-time data during actual operation. This method is static and cannot achieve dynamic adjustment.

[0003] At present, in-situ hot recycling operations have been widely used. There is an urgent need for a method that can reduce manpower consumption and testing time, can test the pavement data of each point on the operation road section, and can dynamically calculate the dosage of the rejuvenator at this point based on these data for adjustment. Summary of the Invention

[0004] To solve the above problems, the present invention provides a model for determining the dosage of a rejuvenator during in-situ hot recycling repair of asphalt pavement. The proportion α of the rejuvenator in the mass of the old asphalt is as follows:

[0005]

[0006] Wherein:

[0007] α - the proportion of the rejuvenator incorporated;

[0008] η mix - the target 60°C kinematic viscosity of the recycled asphalt after mixing;

[0009] β - the proportion of the new asphalt, that is, the proportion of the new asphalt in the total asphalt dosage;

[0010] η JIP - the 60°C kinematic viscosity of the asphalt in the asphalt mixture of the part being operated;

[0011] η new—— Kinematic viscosity of the new asphalt at 60 °C;

[0012] η re —— Kinematic viscosity of the rejuvenator at 60 °C.

[0013] Based on the above scheme, the proportion β of the new asphalt is determined by the following method:

[0014]

[0015] Where:

[0016] γ —— Optimum asphalt content of the recycled asphalt mixture;

[0017] k —— Dosage of the old asphalt mixture;

[0018] δ —— Asphalt content of the old asphalt mixture.

[0019] Based on the above scheme, η JIP is obtained from the asphalt 60 °C viscosity-temperature-asphalt mixture mixing viscosity resistance model formula,

[0020] η JIP =η 60℃ =G(T,F)

[0021] Where: η 60℃ —— Kinematic viscosity of the asphalt at 60 °C (Pa·s);

[0022] T —— Temperature of the asphalt mixture (°C);

[0023] F —— Mixing viscosity resistance of the asphalt mixture (N).

[0024] Based on the above scheme, the construction method of the asphalt 60 °C viscosity-temperature-asphalt mixture mixing viscosity resistance model is as follows:

[0025] (1) Select several samples of road petroleum asphalt with different grades and prepare corresponding asphalt mixture samples using these asphalt samples;

[0026] (2) Test and obtain the 60 °C kinematic viscosity data of each grade of asphalt sample, and through testing, obtain the asphalt mixture temperature-asphalt mixture mixing viscosity resistance data of each asphalt sample corresponding to several different temperatures;

[0027] (3) Obtain several sets of "asphalt 60 °C viscosity-asphalt mixture temperature-asphalt mixture mixing viscosity resistance" data for each grade of asphalt sample and the corresponding asphalt mixture sample;

[0028] (4) Use the origin software to perform surface fitting on the data obtained in step (3) to obtain the model relational expression of "asphalt 60°C viscosity - temperature - asphalt mixture mixing adhesion resistance":

[0029] η 60℃ = G(T,F).

[0030] Based on the above solution, the selection rules for the road petroleum asphalt samples and asphalt mixture samples in step (1) are as follows: The closer the asphalt grade and the gradation type of the asphalt mixture sample are to the asphalt grade and the asphalt mixture gradation type of the pavement to be repaired, the larger the number of simulated asphalt sample grades, and the more data on asphalt mixture temperature - asphalt mixture mixing adhesion resistance, which will help improve the fitting effect of the model.

[0031] Based on the above solution, the different temperatures in step (2) refer to the heating temperatures commonly used during the repair of asphalt pavements.

[0032] A method for determining the dosage of regenerant during the in-situ hot recycling repair of asphalt pavements. When using the above model for determination, it is necessary to measure the mixing adhesion resistance and temperature of the old asphalt mixture in the section to be constructed.

[0033] A server includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the above method steps are implemented.

[0034] A computer-readable storage medium stores a computer program. The computer program, when executed by a processor, implements the above method steps.

[0035] A method for in-situ hot recycling repair of asphalt pavements uses the above model to determine the amount of regenerant to be added during the repair.

[0036] Through the model for determining the dosage of regenerant during the in-situ hot recycling repair of asphalt pavements in this application, the dosage of regenerant can be dynamically adjusted quickly according to the data of the asphalt pavement to be repaired. This model effectively solves the problem that the traditional method cannot update the dosage of regenerant according to the real-time aging situation of each working point. In this model, the 60°C dynamic viscosity data of asphalt is obtained through the asphalt 60°C viscosity - temperature - asphalt mixture mixing adhesion resistance model, thus solving the problem of time-consuming and laborious traditional methods. By applying this model, the efficiency and accuracy of the in-situ hot recycling repair of asphalt pavements can be improved, thereby effectively extending the service life of the pavement. Description of the Drawings

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art.

[0038] Figure 1 In Example 2 of this application, the model diagram of the relationship between the viscosity of asphalt at 60°C - temperature - the mixing viscosity resistance of asphalt mixture is simulated. Specific embodiments

[0039] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in combination with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the scope of protection of the present invention.

[0040] Example 1

[0041] This application provides a model for determining the dosage of regenerant during in-situ hot recycling repair of asphalt pavement. The specific model is as follows:

[0042]

[0043] α—the proportion of regenerant, the proportion of regenerant in the mass of old asphalt;

[0044] η mix —the target dynamic viscosity of the regenerated asphalt at 60°C after mixing; the rule is the viscosity of asphalt with a grade one lower than the asphalt grade of the old pavement at 60°C, which is specifically given in the project overview of the construction;

[0045] β—the proportion of new asphalt, that is, the proportion of new asphalt in the total asphalt in the mixed asphalt mixture (calculated through the optimum asphalt-aggregate ratio of the regenerated asphalt, the dosage of the old asphalt mixture, and the asphalt content in the old asphalt mixture, given in the project overview),

[0046] Among them: γ—the optimum asphalt content of the regenerated asphalt mixture (the optimum asphalt content of the regenerated asphalt mixture should be determined according to the current "Technical Specification for Construction of Highway Asphalt Pavements" (JTG F40), given in the project overview);

[0047] k—the dosage of the old asphalt mixture, determined according to specific construction requirements, given in the project overview;

[0048] δ—the asphalt content of the old asphalt mixture, obtained by asphalt extraction test, given in the project overview;

[0049] η JIP —the dynamic viscosity of the asphalt of the old asphalt mixture in the working part at 60°C;

[0050] ηnew — Dynamic viscosity of the new asphalt at 60 °C;

[0051] η re — Dynamic viscosity of the rejuvenator at 60 °C.

[0052] During the actual construction process, there are differences in the 60 °C dynamic viscosity of asphalt in the old asphalt mixture at each point of the in-situ hot recycling operation section. Therefore, we will calculate the dosage of the rejuvenator applicable to this section according to the 60 °C dynamic viscosity of asphalt in the old asphalt mixture of the working part to achieve a more refined repair effect.

[0053] Currently, the 60 °C dynamic viscosity data of asphalt are basically measured by a vacuum decompression capillary viscometer in accordance with the relevant provisions of the current "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTGE20), or the rotational plate viscosity (RPV) test method is used for special asphalt. However, these methods all require several hours to complete the test. If the 60 °C dynamic viscosity data of asphalt are tested at each working point in the construction section, it will increase the workload and cycle of construction. To solve this technical problem, this application provides a method for quickly obtaining the 60 °C viscosity of RAP asphalt. Specifically:

[0054] In the above formula, η JIP is obtained from the asphalt 60 °C viscosity-temperature-asphalt mixture mixing viscosity resistance model formula;

[0055] η JIP = η 60℃ = G(T,F)

[0056] η 60℃ — Dynamic viscosity of asphalt at 60 °C (Pa·s);

[0057] T — Temperature of the asphalt mixture (°C);

[0058] F — Mixing viscosity resistance of the asphalt mixture (N).

[0059] The above asphalt 60 °C viscosity-temperature-asphalt mixture mixing viscosity resistance model is constructed by the following method:

[0060] (1) Select several road petroleum asphalt samples with different grades and prepare corresponding asphalt mixture samples using these asphalt samples;

[0061] The selection rules for road petroleum asphalt samples and asphalt mixture samples are as follows: the closer the asphalt grade and the gradation type of the asphalt mixture sample are to the asphalt grade and the asphalt mixture gradation type of the pavement to be repaired, and the larger the number of selected asphalt grades, the better the model fitting effect. Therefore, in order to improve the accuracy of the model, it is preferred to select the same asphalt grade as the construction section and use the asphalt of this grade to make asphalt mixture samples with the same gradation type as the construction section. Then, several asphalt samples of grades above and below this asphalt grade (for example, 2 samples are selected above and below) are selected and asphalt mixture samples are made.

[0062] (2) Test the 60°C dynamic viscosity data of each grade of asphalt sample, and obtain the asphalt mixture temperature - asphalt mixture mixing viscosity resistance data of each asphalt mixture sample corresponding to each asphalt sample at several different temperatures (the temperature values are the commonly used heating temperatures of asphalt pavements, the more the better, for example, five are selected: 120°C, 130°C, 140°C, 150°C, 160°C).

[0063] Specifically, the more the asphalt mixture temperature - asphalt mixture mixing viscosity resistance data, the better the model fitting effect.

[0064] (3) Obtain several "asphalt 60°C viscosity - asphalt mixture temperature - asphalt mixture mixing viscosity resistance" data for each grade of asphalt sample and the corresponding asphalt mixture sample.

[0065] (4) Use origin software to perform surface fitting on the data obtained in step (3) to obtain the model relationship formula of "asphalt 60°C viscosity - temperature - asphalt mixture mixing viscosity resistance":

[0066] η 60℃ = G(T,F).

[0067] Example 2

[0068] This application provides an example for constructing an asphalt 60°C viscosity - temperature - asphalt mixture mixing viscosity resistance model, which is as follows:

[0069] Construct a model with 5 groups of road petroleum asphalt samples of grades 130, 110, 90, 70, 50 and AC - 20 asphalt mixture samples:

[0070] (1) Prepare 5 groups of road petroleum asphalt samples of grades 130, 110, 90, 70, 50 and AC - 20 asphalt mixture samples;

[0071] Specifically, select the asphalt grade commonly used in asphalt pavement construction as the asphalt sample grade. The asphalt sample should be prepared according to the relevant provisions of the current "Test Procedures for Bitumen and Bituminous Mixtures in Highway Engineering" (JTGE20); it should be mixed and prepared into asphalt mixtures corresponding to the corresponding asphalt grading types according to the relevant provisions of the current "Technical Specifications for Construction of Highway Asphalt Pavements" (JTG F40) and "Test Procedures for Bitumen and Bituminous Mixtures in Highway Engineering" (JTGE20). After mixing, it can be used as an asphalt mixture sample and should be tested in a timely manner to prevent the change of the 60°C viscosity of the asphalt in the asphalt mixture sample.

[0072] (2) For each grade of asphalt sample, the 60°C dynamic viscosity data should be tested according to the test method T0620 in the current "Test Procedures for Bitumen and Bituminous Mixtures in Highway Engineering" (JTGE20); put the asphalt mixture corresponding to the asphalt grade into the container of the asphalt mixture adhesion resistance test system. The weight measuring device tests the weight of the sample in the container, the stirring needle stirs the asphalt mixture, the dynamometer connected to the stirring needle tests the adhesion resistance, and the thermometer inside the container tests the temperature to obtain 5 "asphalt mixture temperature - asphalt mixture stirring adhesion resistance" data of the asphalt mixture sample (the temperatures are the five commonly used heating temperatures of asphalt pavements, 120°C, 130°C, 140°C, 150°C, and 160°C).

[0073] (3) For each grade, 5 "asphalt 60°C viscosity - asphalt mixture temperature - asphalt mixture mixing adhesion resistance" data are obtained, and a total of 25 groups of data are shown in Table 1.

[0074] Table 1 Data table of "asphalt 60°C viscosity - asphalt mixture temperature - asphalt mixture mixing adhesion resistance"

[0075]

[0076]

[0077] (4) Use origin software to perform surface fitting on the 25 "asphalt 60°C viscosity - temperature - asphalt mixture mixing adhesion resistance" data of the five asphalt grades. The result is as Figure 1 shown, and the relationship formula of "asphalt 60°C viscosity - temperature - asphalt mixture mixing adhesion resistance" is obtained:

[0078] η 60℃ =1 - 0.00118T 3 + 0.50103T 2 - 53.54T + 0.905F 3 - 26.172F 2 + 312.088F

[0079] η 60℃ —— Dynamic viscosity of asphalt at 60°C (Pa·s);

[0080] T—the temperature of the asphalt mixture (°C);

[0081] F—the stirring adhesion resistance of the asphalt mixture (N).

[0082] The R value of this relational expression 2 can reach 0.91.

[0083] Remark: The more asphalt grades are used in the surface fitting, the more data of "asphalt mixture temperature - asphalt mixture stirring adhesion resistance" corresponding to each asphalt grade, and the closer the gradation type is to the asphalt mixture gradation type of the recycled pavement, the better the surface fitting effect.

[0084] Example 3

[0085] This example takes the hot recycling operation section of a secondary highway with a total length of 9.351 km on the Bin Yu Line (42K + 000 - 51K + 351) of the national highway as an example. The 60°C dynamic viscosity η of the new asphalt used in the operation new is 187 Pa·s, and the target 60°C dynamic viscosity η of the asphalt in the recycled asphalt mixture mix is 255 Pa·s; the recycling agent used is the LURA high-performance recycling agent, and its 60°C dynamic viscosity η re is 8 Pa·s; the type of asphalt mixture on the surface layer of the old road surface is AC - 20, the old asphalt is 70# base asphalt, and after recycling, it is required that the asphalt reaches the 60°C dynamic viscosity of 50# base asphalt. Through the extraction test, the asphalt content δ in the old asphalt mixture is 3.9%, the dosage k of the old asphalt mixture is 80%, and through the mix design of the hot recycled asphalt mixture, the optimum asphalt content γ is determined to be 5.47%, and the calculated new asphalt dosage β is 43%.

[0086] During the construction process, the model of Example 1 is used to determine the dosage of the recycling agent. For different road sections, the 60°C dynamic viscosity of the asphalt in the old asphalt mixture will vary. Therefore, we will calculate the recycling agent dosage applicable to this road section according to the 60°C dynamic viscosity η JIP of the asphalt in the old asphalt mixture of the part under operation, so as to achieve a more refined repair. If the 60°C dynamic viscosity data of the asphalt is measured at each point in the construction section, it will increase the construction workload and construction period. Therefore, we use the model in Example 2 to predict the 60°C dynamic viscosity of the asphalt in the old asphalt mixture at each point of the corresponding road section.

[0087] Specifically, during the operation, collect the asphalt mixture in the operation section, measure its stirring adhesion resistance and obtain the temperature corresponding to this stirring adhesion resistance, and then the 60°C dynamic viscosity of the asphalt in the mixture of the operation section can be obtained by using the model of Example 2.

[0088] Collect 4 portions of asphalt mixture on the working section and measure relevant data, and obtain the dynamic viscosity of asphalt at 60°C from the model in Example 2, as shown in Table 2.

[0089] Table 2 "Data Table of Asphalt Viscosity at 60°C - Temperature - Mixing Viscous Resistance of Asphalt Mixture"

[0090]

[0091] Take the average value of the dynamic viscosity of asphalt at 60°C of the four asphalts as the dynamic viscosity η of asphalt in the asphalt mixture of the working part. JIP = 410 Pa·s.

[0092] Through the calculation of the model in Example 1, the addition ratio α of the regenerant can be obtained as 6.1%.

[0093] The addition amount of the regenerant determined according to the relevant regulations of the current "Technical Specification for Highway Asphalt Pavement Recycling" (JTG / T 5521) for this project is 6.2%, which is very close to the value calculated by this method, thus indicating the feasibility of the method of this application.

[0094] The above are only the preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention are all included in the protection scope of the present invention.

Claims

1. A method for determining the dosage of regenerant during in-situ hot recycling repair of asphalt pavement, characterized in that: The proportion of the regenerant in the old asphalt by mass is as follows: Wherein: —— Incorporation ratio of the regenerant; ——Target 60°C dynamic viscosity of the regenerated asphalt after mixing; —— The proportion of the new asphalt, i.e., the proportion of the new asphalt in the total asphalt consumption; —— Dynamic viscosity of asphalt in the asphalt mixture being worked at 60°C; —— kinematic viscosity of the new asphalt at 60 °C; ——The kinematic viscosity of the regenerant at 60 °C; It is obtained from the asphalt viscosity-temperature-asphalt mixture mixing viscosity resistance model formula at 60 °C, = =G(T, F) Wherein: —— dynamic viscosity of asphalt at 60 °C (Pa·s); T - the temperature of the asphalt mixture (°C); F - the stirring adhesion resistance of the asphalt mixture (N); The construction method of the asphalt 60°C viscosity-temperature-asphalt mixture mixing adhesion resistance model is as follows: (1) Select several samples of road petroleum asphalt with different grades and use these asphalt samples to prepare corresponding asphalt mixture samples; (2) Test and obtain the 60°C dynamic viscosity data of each grade of asphalt sample, and through testing, obtain the asphalt mixture temperature-asphalt mixture stirring adhesion resistance data of each asphalt sample corresponding to several different temperatures; (3) Obtain several "asphalt 60°C viscosity-asphalt mixture temperature-asphalt mixture mixing adhesion resistance" data for each grade of asphalt sample and the corresponding asphalt mixture sample; (4) Use origin software to perform surface fitting on the data obtained in step (3) to obtain the "asphalt 60°C viscosity-temperature-asphalt mixture mixing adhesion resistance" model relationship formula: =G(T,F).

2. The method for determining the dosage of regenerant during in-situ hot recycling repair of asphalt pavement according to claim 1, characterized in that: ； Wherein: γ - the optimal asphalt content of the recycled asphalt mixture; k - the dosage of the old asphalt mixture; δ - the asphalt content of the old asphalt mixture.

3. The method for determining the dosage of regenerant during in-situ hot recycling repair of asphalt pavement according to claim 1, characterized in that: The selection rules for the road petroleum asphalt samples and asphalt mixture samples in step (1) are as follows: the closer the asphalt grade and the gradation type of the asphalt mixture sample are to the asphalt grade and the asphalt mixture gradation type of the pavement to be repaired, the more asphalt grades, and the more asphalt mixture temperature-asphalt mixture stirring adhesion resistance data, the better the model fitting effect.

4. The method for determining the dosage of the regenerant during in-situ hot recycling repair of asphalt pavement according to claim 1, characterized in that, The different temperatures in step (2) refer to the common heating temperatures during asphalt pavement repair.

5. A server, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, The processor implements the method steps described in any one of claims 1-4 when executing the computer program.

6. A computer-readable storage medium storing a computer program, characterized in that, The computer program implements the method steps described in any one of claims 1-4 when executed by the processor.

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