A modified asphalt waste rubber reverse adaptation method based on multi-dimensional variation characteristics

Abstract

The application discloses a modified asphalt waste rubber reverse adaptation method based on multi-dimensional variation characteristics, which comprises the following steps: obtaining measured data of waste rubber variation characteristic parameters; judging the deviation quantity and the deviation degree of the measured data according to the allowable interval of the parameters corresponding to the high-temperature and storage stability performance of the modified asphalt; preliminarily judging the performance adaptation grade of the waste rubber; calculating the performance prediction value of the waste rubber according to a high-temperature and storage stability performance prediction model, and rechecking the adaptation grade of the waste rubber according to the target performance interval; and comprehensively grading the waste rubber according to the two performance adaptation grades after the rechecking. The application realizes the directional adaptation between the waste rubber variation characteristic parameters and the target performance of the modified asphalt by constructing a waste rubber reverse adaptation mechanism facing the target performance demand of the modified asphalt, improves the waste rubber screening efficiency, reduces the engineering trial production cost, and has good engineering application value.

Description

Technical Field

[0001] This invention belongs to the technical field of asphalt pavement material design and solid waste resource utilization, and particularly relates to a reverse adaptation method for waste rubber used in modified asphalt based on multidimensional variation characteristics. Background Technology

[0002] With the continuous growth of car ownership and road transportation scale, the amount of waste rubber materials such as waste tires is constantly increasing. Using waste rubber for asphalt modification can not only realize the resource utilization of waste rubber, but also improve the road performance and service performance of asphalt materials. Therefore, waste rubber has important application value in the field of asphalt pavement materials.

[0003] Currently, for waste rubber powder used in asphalt modification, relevant technologies mainly focus on setting control ranges for macroscopic physicochemical indicators such as particle size, rubber content, ash content, and relative density, and then use these to determine compliance or classify grades. Existing standards mostly classify different mesh grades based on the particle size distribution of the rubber powder, or conduct preliminary evaluations based on the hydrocarbon content of the rubber. However, these methods are mainly based on empirical evaluation using single or a small number of physicochemical indicators, and do not fully consider the differences in the internal composition and structure of waste rubber and their impact on the performance of modified asphalt, making it difficult to meet the needs of performance control and precise application of modified asphalt.

[0004] The variability of waste rubber is mainly reflected in several aspects, including rubber type, vulcanization system, carbon black content and dispersion state, and degree of aging and degradation. These variability characteristics directly affect the swelling behavior, interfacial bonding ability, and spatial network structure formation process of rubber powder in asphalt, thus significantly impacting the high-temperature stability and storage stability of modified asphalt. Due to differences in internal composition and structure, waste rubber from different sources and batches often exhibits strong dispersion in its modification effect, which can easily lead to insufficient performance stability of modified asphalt.

[0005] However, most existing technologies adopt a positive evaluation model, which involves performance testing and applicability evaluation based on the existing characteristic parameters of waste rubber materials, and determining their application scope accordingly. This lacks a systematic analysis of the multidimensional variation characteristics of waste rubber and their impact on modification effects. In practical engineering applications, the use of waste rubber for modified asphalt still mainly relies on experience-based material selection and repeated trial mixing. This not only results in low material utilization efficiency and high trial mixing costs, but also makes it difficult to achieve a precise match between waste rubber materials and the target performance requirements of modified asphalt.

[0006] Therefore, there is an urgent need for a reverse adaptation method for waste rubber in modified asphalt based on multidimensional variation characteristics. Starting from the multidimensional variation characteristics of waste rubber, this method can achieve reverse adaptation and precise screening between waste rubber materials and the target performance requirements of modified asphalt, thereby improving the screening efficiency and performance matching accuracy of waste rubber materials, reducing engineering trial mixing costs, and providing technical support for the precise utilization of waste rubber materials. Summary of the Invention

[0007] The main objective of this invention is to provide a reverse adaptation method for waste rubber used in modified asphalt based on multidimensional variation characteristics. This method can fully consider the multidimensional variation characteristics of waste rubber and its impact on asphalt modification, and solve the problems of existing technologies where waste rubber material screening relies on experience and lacks a target performance-oriented adaptation mechanism. It enables reverse adaptation, grade evaluation, and precise screening of waste rubber materials based on the target modified asphalt performance requirements, providing a basis for the precise utilization and targeted application of waste rubber materials.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: Firstly, a method for reverse adaptation of waste rubber for modified asphalt based on multidimensional variation characteristics includes the following steps: Step S1: Obtain measured data of waste rubber variation characteristic parameters; Step S2: Based on the allowable range of the variation characteristic parameters corresponding to the target high-temperature stability and storage stability of modified asphalt, determine the number and degree of deviation of the measured data of the variation characteristic parameters from the allowable range. Step S3: Based on the number and degree of deviation of the variation characteristic parameters, preliminarily determine the compatibility level of the high temperature stability and storage stability of waste rubber modified asphalt. Step S4: Calculate the predicted values ​​of high temperature stability and storage stability of waste rubber modified asphalt based on the high temperature stability prediction model and the storage stability prediction model. Based on the numerical range of the target high temperature stability and storage stability, verify the compatibility level of waste rubber. If the verification fails, downgrade the compatibility level of high temperature stability and storage stability. Step S5: Based on the matching grades of high-temperature stability and storage stability, the waste rubber is comprehensively graded.

[0009] Furthermore, in step S1, the measured data of the variation characteristic parameters of waste rubber are obtained, specifically including the following steps: Obtain the variable characteristic parameters of the waste rubber to be evaluated, including rubber hydrocarbon content, crosslinking density, Mooney viscosity, average particle size, oxidation index, and carbon black content, and construct a set of variable characteristic parameters for the waste rubber: (1.1); In the formula, U test This is a set of characteristic parameters for the variation of waste rubber. This represents the measured average particle size. This is the test value for the hydrocarbon content of rubber; This is the test value for carbon black content; This represents the test value for crosslinking density; This is the test value for Mooney viscosity; This is the test value for the oxidation index.

[0010] The set of variation characteristic parameters of the waste rubber is used for subsequent high-temperature stability performance adaptation evaluation and storage stability performance adaptation evaluation.

[0011] Furthermore, in step S2, the rutting factor is used to characterize the high-temperature stability of waste rubber modified asphalt, which is obtained through dynamic shear rheology test; the difference in softening points between the upper and lower sections is used to characterize the storage stability of waste rubber modified asphalt, which is obtained through storage stability test and softening point test.

[0012] Furthermore, in step S2, determining the number and degree of deviation of the variant characteristic parameters specifically includes the following steps: The variation characteristic parameters of waste rubber are matched and determined with the allowable range of the variation characteristic parameters corresponding to the target performance. For any target performance, the variation characteristic parameter u test The adaptation determination flag is defined as follows: (2.1); In the formula, This serves as the adaptation determination identifier for the i-th variant feature parameter; This is the lower limit of the allowable interval for the i-th variant feature parameter; Let be the upper limit of the allowed interval for the i-th variant feature parameter.

[0013] Count the number of variable characteristic parameters in waste rubber that do not meet the target allowable range requirements: (2.2); In the formula, N mis The number of variational feature parameters that do not meet the allowable interval requirements; n is the total number of variational feature parameters involved in the deviation judgment.

[0014] When a key variation parameter does not meet the allowable range requirement, its deviation degree is further calculated: when At that time, its degree of deviation ; when At that time, its degree of deviation ; In the formula, δ i denoted as the deviation of the i-th variant feature parameter; the superscript 'test' indicates the test value; the superscripts 'min' and 'max' represent the lower and upper limits of the allowed interval, respectively.

[0015] Furthermore, in step S3, the compatibility level of the high-temperature stability and storage stability of the waste rubber modified asphalt is initially determined, specifically including the following steps: The number of deviations N based on the variation feature parameters mis and the degree of deviation δ i Waste rubber is classified into grades; when When the time is right, it indicates that all the variation characteristic parameters of the waste rubber meet the allowable range requirements and have a high degree of matching with the target high temperature stability and storage stability. Therefore, its corresponding performance adaptation level is classified as Level I adaptation. when When the value is within a certain range, it indicates that the waste rubber has only a small number of variable characteristic parameters that deviate from the allowable range, and the degree of parameter deviation is small, so it still has a certain adaptability. Therefore, its corresponding performance adaptability level is classified as Level II restricted adaptability. when When the value of the waste rubber is negative, it indicates that multiple variable characteristic parameters deviate from the allowable range, or the degree of deviation of the variable characteristic parameters is large, and the risk of mismatch with the target performance is high. Therefore, its corresponding performance adaptation level is classified as Level III mismatch.

[0016] Furthermore, in step S4, the high-temperature stability performance prediction model is determined by the following formula: (4.1); In the formula, H represents the high-temperature stability index of waste rubber modified asphalt. ~ These are the regression coefficients; This refers to the hydrocarbon content of the rubber. Crosslinking density; Mooney viscosity; The average particle size; The storage stability performance prediction model is determined by the following formula: (4.2); In the formula, S is the storage stability index of waste rubber modified asphalt. ~ These are the regression coefficients; Carbon black content; The oxidation index is denoted as .

[0017] Furthermore, in step S4, in order to correct the performance deviation caused by the multi-parameter coupling effect and improve the accuracy of the target performance adaptation evaluation of waste rubber, the variable characteristic parameters of waste rubber are substituted as a whole into the high-temperature stability performance prediction model and the storage stability performance prediction model for target performance verification; the preliminary evaluation results of waste rubber are verified according to the following method: when If the waste rubber fails the high-temperature stability performance test, it is deemed to have passed the test; otherwise, it fails. when If the waste rubber fails the storage stability performance review, it is deemed to have passed. In the formula, , These are the predicted values ​​for high-temperature stability and storage stability of waste rubber-modified asphalt, respectively; H t and S t These are the target high-temperature stability performance index and the target storage stability performance index, respectively. and These are the allowable deviations for high-temperature stability and storage stability, respectively.

[0018] Furthermore, in step S4, the compatibility level of high-temperature stability performance and storage stability performance is downgraded, specifically including the following steps: When waste rubber undergoes high-temperature stability performance verification, its high-temperature stability performance matching level remains unchanged; When waste rubber material fails the high-temperature stability performance review, it indicates that there is still a certain deviation between its performance and the target performance. Therefore, its high-temperature stability performance matching level is downgraded by one level. When waste rubber undergoes storage stability performance verification, its storage stability performance level remains unchanged. When waste rubber material fails the storage stability performance review, it indicates that there is still a certain deviation between its performance and the target performance. Therefore, its storage stability performance adaptation level is downgraded by one level. If the adjusted level is lower than the incompatibility level III, it will be directly judged as unqualified.

[0019] Furthermore, in step S5, the waste rubber is comprehensively graded, specifically including the following steps: Based on the high-temperature stability performance adaptation grade results and storage stability performance adaptation grade results corrected in step S4, waste rubber is comprehensively graded, among which; Based on the verified high-temperature stability performance level G H and the verified storage stability performance level G S Construct a comprehensive grade determination function for waste rubber materials: (5.1); In the formula, G(U) represents the comprehensive grade determination result of the candidate waste rubber material; G H The high-temperature stability rating after verification; G S This represents the verified storage stability performance level.

[0020] Furthermore, in step S5, based on the waste rubber grading results, the engineering disposal strategy for the waste rubber is determined according to the following method. When waste rubber is rated as superior, it indicates that the high-temperature stability and storage stability of the waste rubber meet the performance requirements of the target modified asphalt, and it is recommended to use it directly in the production of the target modified asphalt. When waste rubber is judged to be Grade A, it indicates that the high temperature stability of the waste rubber meets the target performance requirements, but the storage stability is somewhat insufficient. It is recommended to use it in application scenarios with low requirements for storage stability, including on-site construction and short-term storage, or to add compatibilizers for the preparation of target modified asphalt. When waste rubber is classified as Grade B, it indicates that the high temperature stability of the waste rubber meets the basic target requirements, but the storage stability is poor. It is recommended for on-site hot processing and immediate use, but not for long-term storage. When waste rubber is classified as Grade C, it indicates that the storage stability of the waste rubber meets the target requirements, but its high-temperature stability is somewhat insufficient. It is recommended for applications with lower high-temperature performance requirements, such as low-grade roads and light traffic surfaces. When waste rubber is judged to be of qualified grade, it indicates that the high temperature stability and storage stability of the waste rubber are both in a limited fit state, and it is recommended to downgrade it for non-core modified asphalt application scenarios such as joint filler and stress absorption layer. When waste rubber is judged to be in the restricted qualified grade, it indicates that the waste rubber has poor adaptability to storage stability and high temperature stability is in the restricted adaptability state. It is recommended to use it in combination with the superior grade, and the compounding ratio should be determined according to the target performance requirements. When waste rubber is deemed unqualified, it indicates that the high-temperature stability of the waste rubber cannot meet the target performance requirements, and it is recommended to use it for non-modified asphalt applications such as fuel and rubber padding. By conducting dual-target performance adaptation evaluation, target performance review and correction, and comprehensive grade recommendation, the waste rubber can be transformed from experience-based screening to target performance-oriented adaptation and application recommendation.

[0021] Compared with the prior art, the present invention has the following beneficial effects: (1) Starting from the multidimensional variation characteristics of waste rubber, this invention comprehensively considers parameters such as rubber hydrocarbon content, carbon black content, crosslinking density, Mooney viscosity, oxidation index and average particle size to establish a waste rubber variation characteristic parameter system, realizing a unified characterization of the modification characteristics of waste rubber materials from different sources and batches. Compared with the traditional method of evaluating only a single indicator such as particle size or rubber content, it can more comprehensively reflect the differences in the composition structure, aging state and processing performance of waste rubber materials, and improve the accuracy of waste rubber compatibility evaluation. (2) By establishing a correlation model between the variation characteristic parameters of waste rubber and the high temperature stability and storage stability of modified asphalt, this invention realizes the quantitative correlation between the multidimensional variation characteristics of waste rubber and the performance requirements of the target modified asphalt. It can also solve the allowable range of key variation characteristic parameters based on the target performance requirements, thereby pre-adapting and screening the waste rubber materials to be selected for target performance before the preparation and performance test of modified asphalt, reducing ineffective matching and repeated tests, improving the screening efficiency of waste rubber materials, and reducing the cost of engineering tests. (3) This invention realizes the adaptation evaluation and application recommendation of the selected waste rubber by verifying the target performance and classifying the comprehensive grade, which improves the reliability and engineering applicability of the target performance adaptation results, realizes the transformation of waste rubber materials from experience screening to target performance-driven targeted adaptation and application recommendation, and has good engineering application value for promoting the high-value utilization of waste rubber resources and improving the engineering application level of waste rubber modified asphalt. Attached Figure Description

[0022] Figure 1 This is a flowchart of a method for reverse adaptation of waste rubber for modified asphalt based on multidimensional variation characteristics, according to the present invention. Figure 2 This is a scatter plot of the test values ​​of the multidimensional variation characteristic parameters of waste rubber in this invention; wherein, Figure 2 (a) is the average particle size D m , Figure 2 (b) represents the hydrocarbon content of rubber, C. r , Figure 2 (c) represents the carbon black content C. c , Figure 2 (d) represents the crosslinking density V e , Figure 2 (e) represents Mooney viscosity M v , Figure 2 (f) represents the oxidation index O i ; Figure 3 This is a comparison chart of the predicted and measured values ​​of the high-temperature stability performance of this invention. Figure 4 This is a comparison chart of the predicted and measured values ​​of the storage stability performance of this invention. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0024] To improve the accuracy of matching between waste rubber and the target performance requirements of modified asphalt, this invention selects average particle size, rubber hydrocarbon content, carbon black content, crosslinking density, Mooney viscosity, and oxidation index as variation characteristic parameters of waste rubber.

[0025] A variety of representative waste rubber samples from different sources, tire types, service years, and processing methods were selected to cover the significant variability that may exist in actual sources.

[0026] Waste rubber was cleaned, dried, and then mechanically pulverized to prepare waste rubber powder samples. The particle size distribution of the samples was then tested and recorded.

[0027] Variation characteristic parameter testing was performed on waste rubber powder samples: The average particle size D was obtained by sieving test. m , used to characterize the size difference of waste rubber powder particles; The hydrocarbon content (C) of rubber was obtained by solvent extraction test. r It is used to characterize the differences in the composition of waste rubber powder materials; The carbon black content C was obtained by thermogravimetric analysis. c It is used to characterize the differences in reinforcing components of waste rubber powder; Crosslinking density V was obtained by swelling test. e , used to characterize the differences in the internal network structure of waste rubber powder; The Mooney viscosity M was obtained using the Mooney viscosity test. v , used to characterize the differences in the processing flow properties of waste rubber powder; The oxidation index O was obtained by Fourier transform infrared spectroscopy. i It is used to characterize the degree of oxidative aging of waste rubber powder and the difference in surface polarity.

[0028] The above parameters can characterize the variability of waste rubber materials from multiple dimensions such as particle structure, chemical composition, network structure and aging state.

[0029] The test results of average particle size, rubber hydrocarbon content, carbon black content, crosslinking density, Mooney viscosity, and oxidation index of waste rubber powder were compiled to construct a multidimensional variation characteristic parameter set of waste rubber. This set was used for subsequent adaptation analysis of the high-temperature stability and storage stability of waste rubber-modified asphalt. The multidimensional variation characteristic parameter set of waste rubber is expressed as follows: (1); In the formula, U test This is a set of characteristic parameters for the variation of waste rubber. This represents the measured average particle size. This is the test value for the hydrocarbon content of rubber; This is the test value for carbon black content; This represents the test value for crosslinking density; This is the test value for Mooney viscosity; This is the test value for the oxidation index.

[0030] A database of multidimensional variation characteristic parameters of waste rubber was established based on the test results of different waste rubber powder samples, which will be used for subsequent reverse adaptation analysis of target performance.

[0031] Waste rubber powder was added to the base asphalt according to a preset fixed dosage, and modified by high-speed shearing to obtain modified asphalt samples corresponding to different waste rubbers.

[0032] The high-speed shearing process includes control of shearing temperature, shearing rate, and shearing time to ensure that different waste rubber materials are modified under the same process conditions, thereby reducing the impact of differences in preparation processes on performance results.

[0033] Furthermore, to effectively adapt the waste rubber-modified asphalt to the target performance requirements, this invention selects high-temperature stability and storage stability as the target performance characterization indicators. This is because high-temperature stability is one of the most important service properties of waste rubber-modified asphalt, reflecting the effect of waste rubber on improving the asphalt's high-temperature deformation resistance; while storage stability reflects the compatibility and system stability between waste rubber and the base asphalt, and is an important control indicator for the engineering application of waste rubber-modified asphalt. By selecting these two types of performance indicators, the target performance adaptation effect of waste rubber-modified asphalt can be comprehensively evaluated from both aspects of high-temperature deformation resistance and storage stability.

[0034] The rutting factor of waste rubber modified asphalt was obtained by dynamic shear rheology test, which was used to characterize the high temperature stability of waste rubber modified asphalt. The difference in softening point between the upper and lower sections of the waste rubber modified asphalt sample was obtained by storage stability test and softening point test, which was used to characterize the storage stability of waste rubber modified asphalt.

[0035] At least one of correlation analysis, grey relational analysis, sensitivity analysis, or machine learning analysis is used to analyze the influence of each variable characteristic parameter on high-temperature stability and storage stability. Preferably, correlation coefficient analysis is used to calculate the influence coefficients of each variable characteristic parameter on high-temperature stability and storage stability, which are used to characterize the influence of different variable characteristic parameters on the performance of modified asphalt. The high-temperature performance influence coefficient R0 is used to characterize the influence of different variable characteristic parameters on the performance of modified asphalt. iH Calculate using the following formula: (2); In the formula, R iH x is the influence coefficient of the i-th variational characteristic parameter on high-temperature stability; ik Let i be the variation characteristic parameter of the kth waste rubber powder sample; H is the average value of the i-th variant characteristic parameter; k Let be the rutting factor of the kth waste rubber modified asphalt sample; is the average rutting factor of all waste rubber modified asphalt samples; N is the number of waste rubber modified asphalt samples; i is the sequence number of the variation characteristic parameter.

[0036] Storage stability performance influence coefficient R iS Calculate using the following formula: (3); In the formula, R iS S is the influence coefficient of the i-th variational characteristic parameter on storage stability performance; k The difference in softening points between the upper and lower sections of the k-th waste rubber modified asphalt sample; This represents the average difference in softening points between the upper and lower sections of all waste rubber modified asphalt samples.

[0037] When the absolute value of the influence coefficient of high-temperature stability performance corresponding to a certain variation characteristic parameter When the value exceeds the preset threshold for the influence coefficient of high-temperature stability performance, the variation characteristic parameter is determined as the variation characteristic parameter of the influence of high-temperature stability performance, and a set K of variation characteristic parameters of the influence of high-temperature stability performance is constructed. H : (4); When the absolute value of the storage stability performance influence coefficient corresponding to a certain variation characteristic parameter When the value exceeds the preset threshold for the influence coefficient of storage stability performance, the variability feature parameter is determined as the variability feature parameter affecting storage stability performance, and a set K of variability feature parameters affecting storage stability performance is constructed. S : (5); The set of key variation features is used to characterize the core variation parameters that have a significant impact on the modification effect under different target modified asphalt performance requirements.

[0038] The set of variational characteristic parameters K based on the influence of high-temperature stability performance H and the set of variable characteristic parameters K that affect storage stability S Performance prediction models were established to predict the relationship between the variation characteristic parameters of waste rubber and the high-temperature stability and storage stability of modified asphalt.

[0039] Based on the experimental results of different waste rubber powder samples, the correlation between the variation characteristic parameters of high-temperature stability performance and the high-temperature stability performance of modified asphalt was established. The following prediction model for the high-temperature stability performance of modified asphalt was established using multiple linear regression: (6); In the formula, H is the high-temperature stability performance index of waste rubber modified asphalt; α0 is the regression constant term of the high-temperature stability performance prediction model; α1, α2, α3, and α4 are the regression coefficients of the high-temperature performance prediction model corresponding to rubber hydrocarbon content, crosslinking density, Mooney viscosity, and average particle size, respectively.

[0040] Based on the experimental results of different waste rubber powder samples, the correlation between the variation characteristic parameters affecting storage stability and the storage stability of modified asphalt was established. The following prediction model for the storage stability of modified asphalt was established using multiple linear regression: (7); In the formula, S is the storage stability performance index of waste rubber modified asphalt; β0 is the regression constant term of the storage stability performance prediction model; β1, β2, β3, and β4 are the regression coefficients of the storage stability performance prediction model corresponding to oxidation index, crosslinking density, carbon black content, and Mooney viscosity, respectively.

[0041] This invention constructs a database of test values ​​for multidimensional variation characteristic parameters of waste rubber based on data from 50 sets of waste rubber powder samples. The scatter plot of this database is shown below. Figure 2 As shown.

[0042] The 50 waste rubber powder samples were derived from different types of waste tires, different service years, and different processing methods. Their average particle size covered the range of 30 to 400 μm and were used to characterize the variability of particle size and composition of waste rubber powder in actual engineering.

[0043] Using the regression analysis module in Excel, a multiple linear regression analysis was performed on the high-temperature stability performance index (rutting factor) and the variation characteristic parameters to obtain the following high-temperature stability performance prediction model: (8); Similarly, the storage stability performance prediction model is as follows: (9).

[0044] The correlation results between the predicted and measured values ​​of the high-temperature stability performance prediction model and the storage stability performance prediction model are as follows: Figure 3 and Figure 4 As shown.

[0045] Depend on Figure 3 and Figure 4 It can be seen that there is good consistency between the predicted and measured values, with most sample points distributed near the y=x baseline. The determination coefficients of the high-temperature stability performance prediction model and the storage stability performance prediction model are 0.938 and 0.950, respectively, indicating that the established models have high prediction accuracy and reliability, and can be used for the prediction and evaluation of the target performance of waste rubber modified asphalt.

[0046] Based on the application requirements of the target modified asphalt, the target high-temperature stability index H was determined. t and target storage stability performance index S t And set the corresponding allowable deviation for high-temperature stability performance. and storage stability performance allowable deviation ; The high-temperature stability constraint relationship is established according to the following formula: (10); The storage stability performance constraint relationship is established according to the following formula: (11).

[0047] Then, for any variable characteristic parameter affected by high-temperature stability, the remaining variable characteristic parameters affected by high-temperature stability are fixed to the representative values ​​of the corresponding target operating conditions to solve for the corresponding allowable intervals. By fixing the remaining variable characteristic parameters, the interference of multi-parameter coupling on the solution results of the allowable interval of a single variable characteristic parameter is reduced. The high-temperature stability constraint relationship is then solved in reverse to obtain the allowable interval of the variable characteristic parameter that meets the target high-temperature stability requirements. Similarly, the allowable interval of the variable characteristic parameter that meets the target storage stability requirements can be obtained. For convenience, the allowable intervals are uniformly set as follows: It means that, among them, , These are the lower and upper limits of the allowable interval for the i-th variation characteristic parameter, used to determine the number and degree of deviation of the measured data of the variation characteristic parameter from the allowable interval. In specific applications, they are distinguished according to high-temperature stability performance and storage stability performance.

[0048] In summary, before reverse-fitting a waste rubber, it is necessary to obtain a large amount of measured data on the waste rubber's variation characteristic parameters and high-temperature and storage stability performance indicators. Based on this, a universal high-temperature stability performance prediction model and a storage stability performance prediction model should be established. Then, based on these two prediction models and the target high-temperature and storage stability performance of the modified asphalt, the allowable range of the corresponding variation characteristic parameters should be calculated. Afterward, following the method in Example 1, the quantity and degree of parameter deviation of the waste rubber should be determined to preliminarily determine its fit level. Then, the fit level should be verified based on the two prediction models, and the waste rubber should be comprehensively graded based on the final fit level.

[0049] Example 1; like Figure 1 As shown, this embodiment of the invention provides a method for reverse adaptation of waste rubber for modified asphalt based on multidimensional variation characteristics, specifically including the following steps: Step S1: Obtain measured data of the variation characteristic parameters of waste rubber.

[0050] In this embodiment, waste rubber from a certain engineering tire source was selected as the sample to be evaluated. Test data on the variable characteristic parameters of this waste rubber were obtained, including test data on rubber hydrocarbon content, crosslinking density, Mooney viscosity, average particle size, oxidation index, and carbon black content. A set of test values ​​for the variable characteristic parameters of the waste rubber was then constructed. (12); In the formula, U test This is a set of test values ​​for the variation characteristic parameters of waste rubber; the superscript "test" indicates the test value.

[0051] The set of variation characteristic parameters of waste rubber is used for subsequent high-temperature stability performance adaptation evaluation and storage stability performance adaptation evaluation.

[0052] Step S2: Based on the allowable range of the variation characteristic parameters corresponding to the target high-temperature stability and storage stability of modified asphalt, determine the number and degree of deviation of the measured data of the variation characteristic parameters from the allowable range.

[0053] This embodiment takes waste rubber modified asphalt for heavy-duty traffic roads as the target application scenario, and sets the target high-temperature stability performance index, rutting factor H. t =3.0 kPa, target storage stability performance index S t =2.5℃, allowable deviation of high temperature stability performance The allowable deviation in storage stability is 0.5 kPa, preferably 0.3 kPa. The temperature is 0.5℃, preferably 0.3℃.

[0054] Based on formulas (8) and (10), establish the high-temperature stability performance constraint relationship: (13); Establish the storage stability performance constraint relationship according to formulas (9) and (11): (14).

[0055] Based on the target modified asphalt application scenario, road service environment, or target performance requirements, determine the target working condition reference parameter combination corresponding to the key performance-influencing characteristic parameters.

[0056] In this embodiment, the combination of target operating condition variation characteristic parameters is determined based on the typical parameters corresponding to the target road service environment and the target performance requirements. The reference combination of target operating condition variation characteristic parameters for high-temperature stability performance is as follows: (15); In the formula, The combination of reference variation characteristic parameters corresponding to the target operating condition for high-temperature stability performance; These are reference values ​​for rubber hydrocarbon content, crosslinking density, Mooney viscosity, and average particle size, respectively. , , , .

[0057] The reference combination of characteristic parameters for the variation of target operating conditions in storage stability performance is as follows: (16); In the formula, To store the reference variation characteristic parameter combination corresponding to the target operating condition of stable performance; These are reference values ​​for oxidation index, crosslinking density, carbon black content, and Mooney viscosity, respectively. , , , .

[0058] For any given high-temperature key influence characteristic parameter, the remaining high-temperature key influence characteristic parameters are fixed to the representative values ​​of the corresponding target operating conditions. By fixing the remaining key influence characteristic parameters, the interference of multi-parameter coupling on the solution results of the allowable interval of a single key influence characteristic parameter is reduced. The high-temperature stability performance constraint relationship is then solved in reverse to obtain the allowable interval of the variation characteristic parameter that meets the target high-temperature stability performance requirements. (17); Similarly, the allowable range of variation characteristic parameters that meet the target storage stability performance requirements is obtained: (18).

[0059] The allowable ranges for the aforementioned variable characteristic parameters are used for reverse adaptation screening of waste rubber's target properties. By reducing the impact of multi-parameter coupling on the solution results of single-parameter ranges, rapid target performance-oriented pre-screening of waste rubber's variable characteristic parameters is achieved. Among them, crosslinking density and Mooney viscosity both affect high-temperature and storage stability, and their corresponding allowable ranges include both common and distinct ranges.

[0060] By matching the test values ​​of the variation characteristic parameters of waste rubber with the corresponding allowable ranges, the suitability of the waste rubber to be evaluated can be determined.

[0061] For any target performance, the test value of the variation characteristic parameter u test The adaptation determination flag is defined as follows: (19); In the formula, This serves as the adaptation determination identifier for the i-th variant feature parameter; , Let be the lower and upper limits of the allowed interval for the i-th variant feature parameter.

[0062] Count the number of variable characteristic parameters in waste rubber that do not meet the target allowable range: (20); In the formula, N mis The number of variational characteristic parameters that do not meet the allowable range requirements; n is the total number of variational characteristic parameters involved in the deviation judgment, with four variational characteristic parameters each corresponding to high-temperature stability and storage stability.

[0063] When a certain variational characteristic parameter does not meet the allowable range, its deviation degree is further calculated: when At that time, its degree of deviation ; when At that time, its degree of deviation ; In the formula, δ i The deviation of the i-th variant feature parameter is represented by the superscript "test". The superscripts "min" and "max" represent the lower limit and upper limit values, respectively.

[0064] Step S3: Based on the number and degree of deviation of the variation characteristic parameters, preliminarily determine the compatibility level of the high-temperature stability and storage stability of waste rubber modified asphalt.

[0065] Since different variation characteristic parameters have a synergistic effect on the target modified asphalt performance, when the number of variation characteristic parameters deviating from the target working condition allowable range is small and the degree of deviation is small, the selected waste rubber still has a certain ability to adapt to the target performance; however, as the number of variation characteristic parameters that do not meet the target working condition allowable range increases or the degree of parameter deviation increases, the risk of mismatch of the target performance of waste rubber gradually increases.

[0066] Therefore, by comprehensively considering the number and degree of deviation of the variation characteristic parameters, a rule for determining the target performance adaptation level of waste rubber is constructed to achieve a graded evaluation of the target performance adaptation capabilities of different waste rubbers.

[0067] Based on the matching results of the variation feature parameters, the number N of parameter deviations that do not meet the allowable interval requirements. mis and the degree of parameter deviation δ i Waste rubber was comprehensively graded to achieve a preliminary evaluation of the suitability of waste rubber-modified asphalt for high-temperature stability and storage stability. when When the time is right, it indicates that all the variation characteristic parameters of waste rubber meet the allowable range requirements of the target working condition and have a high matching with the performance requirements of the target modified asphalt. Therefore, its corresponding performance adaptation level is classified as Level I adaptation. when When the time is right, it indicates that only a small number of variable characteristic parameters of waste rubber deviate from the allowable range of the target working condition, and the degree of parameter deviation is small, so it still has a certain adaptability. Therefore, its corresponding performance adaptability level is classified as Level II restricted adaptability. when When the waste rubber has multiple variable characteristic parameters that deviate from the allowable range of the target working condition, or the degree of deviation of the variable characteristic parameters is large, the risk of mismatch with the target performance is high. Therefore, its corresponding performance adaptation level is classified as Level III mismatch. Wherein: δ0 is the preset parameter deviation threshold, which is determined according to the target engineering performance requirements, and is preferably 20%.

[0068] In this implementation, the number N of high-temperature performance variation characteristic parameters that do not meet the target allowable range requirements is... mis =0, the number N of storage stability performance variation characteristic parameters that do not meet the target allowable range requirements. mis =1, its degree of deviation Therefore, the high-temperature performance compatibility level of this waste rubber is Level I, and the storage stability performance compatibility level is Level II (limited compatibility).

[0069] Step S4: Calculate the predicted values ​​of high-temperature stability and storage stability of waste rubber modified asphalt based on the high-temperature stability prediction model and the storage stability prediction model. Based on the numerical range of the target high-temperature performance and storage performance, verify the compatibility grade of waste rubber. If the verification fails, downgrade the compatibility of high-temperature stability and storage stability.

[0070] To correct performance deviations caused by multi-parameter coupling and improve the accuracy of target performance adaptation evaluation of waste rubber, the test values ​​of waste rubber variation characteristic parameters are substituted as a whole into the high-temperature stability performance prediction model (Equation 8) and the storage stability performance prediction model (Equation 9) to calculate the corresponding predicted values. , Then based on the predicted value , Perform target performance verification; when If the waste rubber fails the high-temperature stability performance test, it is deemed to have passed the test; otherwise, it fails. when If the waste rubber fails the storage stability performance review, it is deemed to have passed; otherwise, it fails.

[0071] For waste rubber that has already obtained high-temperature stability performance and storage stability performance levels, the corresponding performance levels are further revised based on the target performance verification results: When waste rubber undergoes high-temperature stability performance verification, its high-temperature stability performance compatibility level remains unchanged. When waste rubber fails the high-temperature stability performance review, it indicates that there is still a certain deviation between its overall high-temperature stability performance and the target performance requirements. Therefore, its high-temperature stability performance adaptation level is downgraded by one level. When waste rubber undergoes storage stability performance verification, its storage stability performance adaptation level remains unchanged. When waste rubber fails the storage stability performance review, it indicates that there is still a certain deviation between its overall storage stability performance and the target performance requirements. Therefore, its storage stability performance adaptation level is downgraded by one level. If the adjusted level is lower than the incompatibility level III, it will be directly judged as unqualified.

[0072] In this embodiment, It failed the high-temperature stability performance review; Based on the verification of storage stability performance, the high temperature performance compatibility level of this waste rubber is classified as Level II restricted compatibility, and the storage stability performance compatibility level is classified as Level II restricted compatibility.

[0073] Step S5: Based on the matching grades of high temperature stability and storage stability, the waste rubber is comprehensively graded.

[0074] Based on the high-temperature stability performance adaptation grade results and storage stability performance adaptation grade results obtained in step S4, the waste rubber is comprehensively graded, and the verified high-temperature stability performance grade is denoted as G. H The verified storage stability performance level is denoted as G. S Construct a comprehensive grade determination function for waste rubber: (twenty three).

[0075] Output corresponding engineering disposal strategies based on the comprehensive classification results of waste rubber; When waste rubber is rated as superior, it indicates that the high-temperature stability and storage stability of the waste rubber meet the performance requirements of the target modified asphalt, and it is recommended to use it directly in the production of the target modified asphalt. When waste rubber is judged to be Grade A, it indicates that the high temperature stability of the waste rubber meets the target performance requirements, but the storage stability is somewhat insufficient. It is recommended to use it in application scenarios with low requirements for storage stability, including on-site construction and short-term storage, or to add compatibilizers for the preparation of target modified asphalt. When waste rubber is classified as Grade B, it indicates that the high temperature stability of the waste rubber meets the basic target requirements, but the storage stability is poor. It is recommended for on-site hot processing and immediate use, but not for long-term storage. When waste rubber is classified as Grade C, it indicates that the storage stability of the waste rubber meets the target requirements, but its high-temperature stability is somewhat insufficient. It is recommended for applications with lower high-temperature performance requirements, such as low-grade roads and light traffic surfaces. When waste rubber is judged to be of qualified grade, it indicates that the high temperature stability and storage stability of the waste rubber are both in a limited fit state, and it is recommended to downgrade it for non-core modified asphalt application scenarios such as joint filler and stress absorption layer. When waste rubber is judged to be in the restricted qualified grade, it indicates that the waste rubber has poor adaptability to storage stability and high temperature stability is in a restricted adaptability state. It is recommended to use it in combination with the superior grade, and the compounding ratio should be determined according to the target performance requirements. When waste rubber is deemed unqualified, it indicates that the high-temperature stability of the waste rubber cannot meet the target performance requirements, and it is recommended for use in non-modified asphalt applications such as fuel and rubber padding.

[0076] By conducting dual-target performance adaptation evaluation, target performance review and correction, and comprehensive grade recommendation, the waste rubber can be transformed from experience-based screening to targeted performance adaptation and application recommendation.

[0077] In this embodiment, due to the high temperature stability level G H =Ⅱ, Storage stability performance level G S =Ⅱ, therefore, this waste rubber is judged to be of qualified grade, and it is recommended to downgrade it for non-core modified asphalt application scenarios such as joint filler and stress absorption layer.

[0078] The beneficial effects achieved by the embodiments of the present invention are as follows: (1) Based on waste rubber from different sources, tire types, service years, and processing methods, this invention establishes a multidimensional variation characteristic parameter system, realizing a systematic characterization of the differences in the composition, network structure, and aging state of waste rubber. Compared with the traditional method of evaluating only single indicators such as particle size or rubber content, this method can more comprehensively reflect the differences in the modification characteristics of waste rubber, and improve the accuracy and stability of the evaluation results of the compatibility grade of waste rubber for modified asphalt; (2) Based on the test data of different waste rubber samples, a prediction model for high temperature stability and storage stability was established. Through multiple linear regression analysis, the fitting relationship between the variation characteristic parameters and the target performance was realized. Based on the target performance requirements, the waste rubber can be screened for reverse adaptation of the target performance. Before the preparation and performance test of modified asphalt, the waste rubber with a high degree of matching with the target performance requirements can be identified in advance, thereby reducing invalid matching and repeated tests and improving the screening efficiency of waste rubber. (3) A dual-objective verification and evaluation mechanism for high-temperature stability and storage stability was constructed. Combined with performance verification and correction, comprehensive grading, and engineering disposal strategies, the transformation of waste rubber from experience-based screening to target performance-driven targeted adaptation and engineering disposal was realized. By conducting adaptation level evaluations on different waste rubbers, corresponding selection criteria can be provided for different road service environments and modified asphalt application scenarios, improving the utilization efficiency of waste rubber and the reliability of engineering applications, and demonstrating good engineering application value.

[0079] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of the claims of the present invention pending approval.

Claims

1. A method for reverse adaptation of waste rubber for modified asphalt based on multidimensional variation characteristics, characterized in that: Includes the following steps: Step S1: Obtain measured data of waste rubber variation characteristic parameters; waste rubber variation characteristic parameters include rubber hydrocarbon content, crosslinking density, Mooney viscosity, average particle size, oxidation index, and carbon black content; Step S2: Based on the allowable range of the variation characteristic parameters corresponding to the target high-temperature stability and storage stability of modified asphalt, determine the number and degree of deviation of the measured data of the variation characteristic parameters from the allowable range. The deviation of the variant characteristic parameter is determined by the following formula: （2.1）； （2.2）； In the formula, This serves as the adaptation determination identifier for the i-th variant feature parameter; This is the test value of the i-th variant feature parameter; , Let the lower and upper limits of the allowed interval be defined for the i-th variant feature parameter. The number of variational feature parameters that do not meet the allowable interval; n is the total number of variational feature parameters involved in the deviation judgment; The degree of deviation of the variation characteristic parameters is determined by the following method: when At that time, its degree of deviation ; when At that time, its degree of deviation ; In the formula, δ i The degree of deviation of the i-th variant feature parameter; Step S3: Based on the number and degree of deviation of the variation characteristic parameters, preliminarily determine the compatibility level of the high temperature stability and storage stability of waste rubber modified asphalt. Step S4: Calculate the predicted values ​​of high temperature stability and storage stability of waste rubber modified asphalt based on the high temperature stability prediction model and the storage stability prediction model. Based on the numerical range of the target high temperature stability and storage stability, verify the compatibility level of waste rubber. If the verification fails, downgrade the compatibility level of high temperature stability and storage stability. The high-temperature stability performance prediction model is determined by the following formula: （4.1）； In the formula, H is the high-temperature stability index of waste rubber modified asphalt; ~ These are the regression coefficients; This refers to the hydrocarbon content of the rubber. Crosslinking density; Mooney viscosity; The average particle size; The storage stability performance prediction model is determined by the following formula: （4.2）； In the formula, S is the storage stability index of waste rubber modified asphalt; ~ These are the regression coefficients; Carbon black content; Oxidation index; Step S5: Based on the matching grades of high temperature stability and storage stability, the waste rubber is comprehensively graded.

2. The method for reverse adaptation of waste rubber for modified asphalt based on multidimensional variation characteristics according to claim 1, characterized in that: The high-temperature stability of waste rubber modified asphalt was characterized by the rutting factor, which was obtained through dynamic shear rheological tests. The storage stability of waste rubber modified asphalt was characterized by the difference in softening points between the upper and lower sections, which was obtained through storage stability tests and softening point tests.

3. The method for reverse adaptation of waste rubber for modified asphalt based on multidimensional variation characteristics according to claim 1, characterized in that: In step S3, the compatibility level of the high-temperature stability and storage stability of the waste rubber modified asphalt is initially determined according to the following method: when At that time, the corresponding performance adaptation level is divided into Level I adaptation; when At that time, the corresponding performance adaptation level is classified as Level II restricted adaptation; when At that time, the corresponding performance compatibility level is classified as Level III, which is not compatible.

4. The method for reverse adaptation of waste rubber for modified asphalt based on multidimensional variation characteristics according to claim 1, characterized in that: In step S4, the compatibility grade of the waste rubber is verified according to the following method: when If the waste rubber fails the high-temperature stability performance test, it is deemed to have passed the test; otherwise, it fails. when If the waste rubber fails the storage stability performance review, it is deemed to have passed. In the formula, , These are the predicted values ​​for high-temperature stability and storage stability of waste rubber-modified asphalt, respectively; H t and S t These are the target high-temperature stability performance index and the target storage stability performance index, respectively. and These are the allowable deviations for high-temperature stability and storage stability, respectively.

5. The method for reverse adaptation of waste rubber for modified asphalt based on multidimensional variation characteristics according to claim 1, characterized in that: In step S4, the compatibility level of high-temperature stability performance and storage stability performance is downgraded, specifically including the following steps: When waste rubber undergoes high-temperature stability performance verification, its high-temperature stability performance matching level remains unchanged; When waste rubber materials fail the high-temperature stability performance review, their high-temperature stability performance compatibility level will be downgraded by one level. When waste rubber undergoes storage stability performance verification, its storage stability performance level remains unchanged. When waste rubber materials fail the storage stability performance review, their storage stability performance adaptation level will be downgraded by one level. If the adjusted level is lower than the incompatibility level III, it will be directly judged as unqualified.

6. The method for reverse adaptation of waste rubber for modified asphalt based on multidimensional variation characteristics according to claim 1, characterized in that: In step S5, the waste rubber is comprehensively graded according to the following formula: （5.1）； In the formula, The results of the comprehensive grade assessment of the candidate waste rubber materials; The high-temperature stability performance level after verification; This represents the verified storage stability performance level.

7. The method for reverse adaptation of waste rubber for modified asphalt based on multidimensional variation characteristics according to claim 1, characterized in that: In step S5, based on the waste rubber grading results, the engineering disposal strategy for waste rubber is determined according to the following method; When waste rubber is classified as superior, it is recommended to use it directly in the production of target modified asphalt; When waste rubber is classified as Grade A, it is recommended for use in applications with low requirements for storage stability, or for use in the preparation of target modified asphalt after adding a compatibilizer. When waste rubber is classified as Grade B, it is recommended for on-site hot processing and immediate use, but not for long-term storage. When waste rubber is determined to be grade C (good grade), it is recommended for applications with lower high-temperature performance requirements. When waste rubber is determined to be of acceptable grade, it is recommended to downgrade it for use in non-core areas of the road surface. When waste rubber is determined to be of the restricted grade, it is recommended to use it in combination with the superior grade. When waste rubber is deemed unqualified, it is recommended to use it for unmodified asphalt.

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