Multi-factor climate coupling aging resistance comprehensive evaluation method for asphalt and application thereof

Abstract

The present application belongs to the technical field of road engineering material aging performance evaluation, and specifically relates to a multi-factor climate coupling aging asphalt weather resistance comprehensive evaluation method and application. The asphalt sample is subjected to short-term thermal oxidation aging; the thermal oxidation aged asphalt sample is subjected to four-factor synchronous coupling accelerated aging, the four factors including temperature, humidity, solar radiation and salt spray; the aged asphalt sample is subjected to Fourier transform infrared spectrum testing, the carbonyl index, sulfoxide index and butadiene index are calculated according to the testing results, and then the comprehensive aging index AOI is obtained, so that the weather resistance grade of the asphalt sample is obtained. The present application further calculates four quantitative evaluation indexes of high-temperature rheological aging sensitivity index HRI, fatigue performance comprehensive degradation index FDI and hydrogen spectrum comprehensive aging index HAI, and establishes a comprehensive weather resistance evaluation system with flexible combination of double indexes, three indexes and four indexes, so that the precise determination and grade division of asphalt weather resistance are realized.

Description

Technical Field

[0001] This invention belongs to the technical field of aging performance evaluation of road engineering materials, specifically involving a comprehensive evaluation method and application of asphalt weather resistance under multi-factor climate coupled aging. Background Technology

[0002] Hainan Province is located on the northern edge of the tropics and has a typical tropical monsoon climate. It is characterized by high temperature, high humidity, strong sunshine, and long summer without winter. As an island province, the coastal areas have long been subjected to salt spray erosion, forming a unique extreme service environment with the coupling of temperature, humidity, solar radiation and salt spray. Under this complex environment, asphalt pavement will show significant aging and deterioration in a short period of time, which is manifested as asphalt hardening, brittleness, loss of ductility, fatigue performance decline and adhesion reduction. Ultimately, it will cause early diseases such as rutting, cracking, loosening and peeling of the pavement, which will significantly shorten the service life of the road and increase the maintenance cost. At present, the evaluation methods for asphalt aging at home and abroad still have obvious limitations and are difficult to adapt to the actual engineering needs of Hainan: (1) The aging simulation method is single. Traditional indoor aging methods mainly use single or two-factor simulations such as rotating thin film oven aging (RTFOT), pressure aging container accelerated aging (PAV), and ultraviolet aging. They cannot realize the synchronous coupling of temperature, humidity, light and salt spray, which is very different from the actual aging process of Hainan pavement, and the evaluation results are distorted. (2) The evaluation index system is incomplete. Existing evaluations mostly rely on conventional physical indicators such as penetration, softening point, and ductility, lacking multi-dimensional information such as rheological properties, fatigue damage, microstructure, and functional group evolution, and cannot reveal the true deterioration mechanism of asphalt under coupled environments. (3) It does not reflect regional climate differences. The climate of Hainan Island shows obvious spatial differentiation: the east is humid, the west is dry, the central mountainous area is cool, the south has strong radiation, and the coast has heavy salt fog. However, the existing evaluation methods adopt a unified standard and have not established a climate-zone differentiated evaluation system, resulting in poor engineering guidance. (4) The macro-micro correlation is insufficient. Most methods only focus on macro performance changes and have not established a quantitative relationship between macro rheological indicators and micro functional groups and phase structure, and cannot explain the fundamental mechanism of asphalt aging, hardening, embrittlement, and fatigue decay at the molecular level. (5) It is impossible to distinguish the influence weight of solar radiation, temperature, salt fog, and humidity on asphalt aging, making it difficult to identify the dominant aging factors and hindering targeted anti-aging modification design.

[0003] In summary, existing evaluation methods cannot accurately, comprehensively, and precisely assess the weather resistance of asphalt under the complex climatic coupling environment of Hainan, severely restricting the selection of road engineering materials, optimization of modification schemes, and improvement of pavement durability in Hainan. Therefore, establishing a weather resistance evaluation method for asphalt that can simulate the coupled aging of four factors, cover macro- and micro-scale indicators, adapt to Hainan's climatic zones, and quantify the degree of deterioration is of urgent engineering need and significant scientific importance. Summary of the Invention

[0004] The purpose of this invention is to provide a comprehensive evaluation method and application for asphalt weather resistance under multi-factor climate coupled aging, which solves the problems of unrealistic aging simulation, one-sided evaluation indicators, poor regional adaptability, macro-micro disconnect, and inability to quantify the contribution of coupled factors in the existing technology.

[0005] To achieve the above objectives, this invention provides a comprehensive evaluation method for the weather resistance of asphalt under multi-factor climate-coupled aging, comprising the following steps: S1. Perform preliminary thermo-oxidative aging on the asphalt samples. S2. Accelerate the aging of asphalt samples after thermo-oxidative aging by simultaneous coupling of four factors, namely temperature, humidity, solar radiation and salt spray. S3. Perform Fourier transform infrared spectroscopy on the aged asphalt samples. Calculate the carbonyl index, sulfoxide index, and butadiene index based on the test results. Then, obtain the comprehensive aging index (AOI) according to the following formula, thereby obtaining the weather resistance grade of the asphalt sample:

[0006] In the formula, CI, SI, and BI are the carbonyl index, sulfoxide index, and butadiene index, respectively; aged represents the aged sample, and unaged represents the unaged sample; the larger the AOI value, the deeper the aging degree of the asphalt sample.

[0007] Furthermore, in step S3, the weather resistance level includes Level I slight aging, with an AOI value < 1.5; Level II moderate aging, with 1.5 ≤ AOI value < 2.2; Level III severe aging, with 2.2 ≤ AOI value < 3.0; and Level IV extreme aging, with an AOI value ≥ 3.0.

[0008] Furthermore, step S3 also includes: conducting rheological property tests on the aged asphalt samples, and then obtaining the high-temperature rheological aging sensitivity index (HRI) according to the following formula:

[0009] In the formula, G* / sinδ is the rutting factor at 60℃, R is the recovery rate at 3.2kPa, and J is the non-recoverable creep compliance at 3.2kPa; the larger the HRI value, the more severe the high-temperature hardening embrittlement of the asphalt sample after coupled aging.

[0010] Furthermore, step S3 also includes: conducting rheological property tests on the aged asphalt samples, and then obtaining the fatigue performance comprehensive deterioration index FDI according to the following formula:

[0011] In the formula, N fThe fatigue life measured by linear amplitude scanning test for rheological property testing. The FDI value represents the fatigue factor; the larger the FDI value, the more severe the fatigue performance degradation of the asphalt sample after coupled aging.

[0012] Furthermore, step S3 also includes: performing nuclear magnetic resonance (NMR) 1H spectroscopy on the aged asphalt sample, analyzing the H spectral data, and obtaining the specific structural hydrogen ratio H. b Total hydrogen molar content of aliphatic chains H β +H γ Then, the hydrogen spectrum comprehensive aging index (HAI) is calculated according to the following formula:

[0013] In the formula, H b For specific structural hydrogen ratios, corresponding to the hydrogens on unsaturated alkenes in Table 1, the following methods are used: 1 The relative molar content calculated by H-NMR integral area, i.e., the percentage of the peak area in that interval to the total peak area of ​​the full spectrum; H β +H γ The HAI value represents the total hydrogen molar content of the aliphatic chain; the higher the HAI value, the more severe the change in molecular structure of the asphalt sample after coupled aging.

[0014] Furthermore, after step S3, the method further includes: taking at least two of the four quantitative evaluation indicators, namely the High Temperature Rheological Aging Sensitivity Index (HRI), the Fatigue Performance Comprehensive Deterioration Index (FDI), and the Hydrogen Spectrum Comprehensive Aging Index (HAI), and performing an equal-weighted geometric average to obtain the comprehensive weather resistance evaluation level. The final output based on the evaluation results of each indicator includes the weather resistance level, coupled aging and degradation mechanism, degree of influence of each environmental factor, recommended applicable climate zone, and modification and optimization suggestions.

[0015] Furthermore, in step S1, the preliminary thermo-oxidative aging is carried out in an air atmosphere at 163±5℃ for 4-6 hours to simulate the thermo-oxidative aging process of asphalt mixture mixing, paving, and compaction. And / or, the asphalt sample to be tested includes base asphalt, SBS modified asphalt, high viscosity modified asphalt, or rubber modified asphalt.

[0016] Furthermore, in step S2, the temperature setting range is 60-70℃, the humidity setting range is 70%-90%, and the solar radiation intensity setting range is 700-1100W / m². 2 The salt spray solution is a 0wt%-15wt% NaCl solution; the aging time for the four factors to be synchronously coupled is 12-20 days.

[0017] Furthermore, the conditions for the four factors to be simultaneously coupled and accelerate aging are: temperature 70℃, humidity 90%, and radiation 1100W / m². 2Salt concentration 15%, aged for 16 days; Alternatively, the following parameters could be used: temperature 65℃, humidity 85%, radiation 700W / m². 2 Salt concentration 10%, aging for 16 days, corresponding to the humid climate zone in northern Hainan; Alternatively, the following parameters could be used: temperature 65℃, humidity 90%, radiation 900W / m². 2 Salt concentration 10%, aging for 16 days, corresponding to the humid climate zone in eastern Hainan; Alternatively, the following parameters could be used: temperature 60℃, humidity 90%, radiation 700W / m². 2 No salt spray, aged for 16 days, corresponding to the humid climate of the central mountainous region of Hainan; Alternatively, the following parameters could be used: temperature 70℃, humidity 75%, radiation 1100W / m². 2 Salt concentration 15%, aging for 16 days, corresponding to the climate of the southern semi-arid and semi-humid region of Hainan; Alternatively, the following parameters could be used: temperature 70℃, humidity 70%, radiation 1100W / m². 2 Salt concentration 15%, aging for 16 days, corresponding to the climate of the western semi-arid region of Hainan; This invention also provides an application of the comprehensive evaluation method for asphalt weather resistance under multi-factor climate coupling aging as described above, which can be used for asphalt material selection, pavement design, quality inspection or old road evaluation. Preferably, when selecting asphalt materials, the evaluation is carried out using the equal-weighted geometric mean of two indicators: AOI+HRI or AOI+FDI. When used for pavement design, the three indicators AOI+HRI+FDI are evaluated using an equal-weighted geometric average. When used for quality inspection, the two indicators are evaluated together with the four indicators of AOI+HRI+FDI+HAI with equal weights using a geometric mean. When used for old road assessment, the three indicators FDI+HRI+CNI are evaluated using an equal-weighted geometric average.

[0018] Compared with the prior art, the above-described technical solutions conceived in this invention mainly have the following beneficial effects: 1. This invention provides a comprehensive evaluation method for asphalt weather resistance under multi-factor climate coupled aging. Through indoor accelerated aging tests of four factors coupled (temperature, humidity, light, and salt), combined with macroscopic physical properties, rheological characteristics, fatigue performance, microscopic functional groups and phase structure, an evaluation system is constructed that combines universal indicators for the entire region with climate-zone differentiated indicators, so as to achieve accurate determination of asphalt weather resistance, classification of deterioration levels and recommendation of applicable areas.

[0019] 2. This invention realistically simulates the extreme four-field coupled environment of Hainan: For the first time, it achieves simultaneous coupled aging of temperature, humidity, light, and salt spray, highly consistent with the aging behavior of road surfaces in real-world conditions, solving the distortion problem of traditional single-factor simulations. It establishes a multi-scale integrated evaluation system: rheological properties, fatigue performance, and infrared spectroscopy, realizing a full-chain evaluation of "macroscopic performance - rheological behavior - microstructure - molecular evolution." It accurately identifies the dominant aging factors: clearly defining the order of influence of solar radiation > temperature > salt spray > humidity, providing a scientific target for anti-aging modification. The core indicators have extremely high sensitivity and evaluation accuracy.

[0020] 3. This invention addresses the combined effects of high temperature, high humidity, strong solar radiation, and high salt spray in Hainan region, enabling the identification of the weather resistance evolution law of SBS modified asphalt, the determination of the degree of deterioration, and the comprehensive evaluation of its durability level. Attached Figure Description

[0021] Figure 1 This is a flowchart for evaluating a combination of indicators. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0023] A comprehensive evaluation method for the weather resistance of asphalt under complex climate coupled aging in Hainan region includes the following steps: Step 1: Preparation of test raw materials and sample preparation The asphalt to be tested was selected, with SBS modified asphalt as the main focus, but base asphalt, high-viscosity modified asphalt, and rubber modified asphalt could also be used. SBS modified asphalt was prepared according to the test requirements. The asphalt was subjected to short-term aging by placing the asphalt samples in a thin-film oven and aging them at 163℃ for 5 hours, simulating the thermo-oxidative aging process of asphalt mixture mixing, paving, and compaction.

[0024] Step Two: Analysis of Hainan's Climate Characteristics and Determination of Multi-Factor Coupled Aging Test Scheme Based on the climatic characteristics of Hainan Island, including temperature, humidity, solar radiation, and salt fog concentration, the entire island is divided into five climatic micro-regions: the northern humid region, represented by Haikou, characterized by high temperature, high humidity, moderate salt fog, and moderate radiation; the eastern humid region, represented by Qionghai, characterized by high humidity, high salt fog, and moderate radiation; the central mountainous humid region, represented by Wuzhishan, characterized by low temperature, highest humidity, no salt fog, and weak radiation; the southern semi-arid and semi-humid region, represented by Sanya, characterized by strong radiation, high temperature, moderate humidity, and high salt fog; and the western semi-arid region, represented by Dongfang, characterized by high temperature, low humidity, strong radiation, and high salt fog. Key parameters for coupled aging were determined as follows: temperature 60℃, 65℃, 70℃; humidity 70%, 80%, 90%; solar radiation intensity 700W / m². 2 900W / m 2 1100W / m 2 (Simulated by xenon lamp irradiation); salt spray concentrations of 5%, 10%, and 15% NaCl solution; aging time of 16 days. A combined system of xenon lamp aging test chamber and salt spray test chamber was used to conduct accelerated aging with four factors simultaneously coupled.

[0025] Step 3: Multi-scale performance testing of asphalt after coupled aging Comprehensive tests were conducted on asphalt samples with different durations of undaged, short-term aged, and coupled-aged conditions. Rheological properties were tested using a dynamic shear rheometer, with temperature scanning used to obtain the complex shear modulus G*, phase angle δ, rutting factor G* / sinδ, and fatigue factor G*·sinδ. A linear amplitude scanning test was then performed to calculate the fatigue life N. f Multiple stress creep recovery tests were conducted to obtain the recovery rate R and the irrecoverable creep compliance Jnr. Chemical composition was determined using Fourier transform infrared spectroscopy, and the carbonyl index CI, sulfoxide index SI, and butadiene index BI were calculated. Molecular structure was determined using proton NMR spectroscopy, and the H₂O₅ index was calculated. b H β +H γ content.

[0026] Step 4: Calculation of Comprehensive Aging Evaluation Indicators Four quantitative evaluation indicators were calculated: the comprehensive aging index AOI, the high temperature rheological aging sensitivity index HRI, the comprehensive fatigue performance degradation index FDI, and the comprehensive aging index HAI based on hydrogen spectrum.

[0027] Step 5: Comprehensive Evaluation Based on Multiple Indicators The evaluation criteria are flexibly combined according to the purpose and engineering requirements: Two-indicator combinations use an equal-weighted geometric average, suitable for rapid screening; three-indicator combinations use an equal-weighted geometric average, suitable for in-depth evaluation; four-indicator combinations are defined as the Comprehensive Weather Resistance Index (CNI), using an equal-weighted geometric average, suitable for comprehensive evaluation. The following grading standards are uniformly adopted: Grade I Excellent (combination value < 1.5), Grade II Good (1.5 ≤ combination value < 2.2), Grade III Poor (2.2 ≤ combination value < 3.0), Grade IV Not Applicable (combination value ≥ 3.0).

[0028] Step Six: Output Evaluation Report The final output includes: weather resistance rating, coupled aging and degradation mechanism, degree of influence of various environmental factors, recommended applicable climate zones, and modification and optimization suggestions.

[0029] Example Extreme aging conditions Weather resistance evaluation of SBS modified asphalt for a highway in Hainan. Sample preparation: Commonly used SBS modified asphalt in engineering was selected and subjected to short-term TFOT aging (aging at 163℃ for 5 hours; this step is also required for all subsequent comparative samples). Coupled aging conditions: temperature 70℃, humidity 90%, radiation 1100W / m². 2 Salt concentration 15%, aged for 16 days. The following comparative examples differ from the examples only in the coupling aging conditions.

[0030] Comparative Example 1 Corresponding zone: Northern humid region Coupling aging conditions: temperature 65℃, humidity 85%, radiation 700W / m 2 Salt concentration 10%, aged for 16 days.

[0031] Comparative Example 2 Corresponding zone: Eastern humid region Coupling aging conditions: temperature 65℃, humidity 90%, radiation 900W / m 2 Salt concentration 10%, aged for 16 days.

[0032] Comparative Example 3 Corresponding zone: Humid mountainous region in central China Coupling aging conditions: temperature 60℃, humidity 90%, radiation 700W / m 2 Salt spray-free, aged for 16 days.

[0033] Comparative Example 4 Corresponding region: Southern semi-arid and semi-humid area Coupling aging conditions: temperature 70℃, humidity 75%, radiation 1100W / m 2 Salt concentration 15%, aged for 16 days.

[0034] Comparative Example 5 Corresponding region: Western semi-arid area Coupling aging conditions: temperature 70℃, humidity 70%, radiation 1100W / m 2 Salt concentration 15%, aged for 16 days.

[0035] It should be noted that the above comparative examples of the present invention do not represent experiments outside the scope of protection of the present invention, but are only comparisons of extreme aging conditions compared with the examples.

[0036] To verify the scientific validity, accuracy, and discriminative power of the method of this invention, the performance of the asphalt in the examples and comparative examples before and after coupled aging was compared with the relevant methods in the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG3410-2025). The results are as follows: (1) Comparative analysis of aging index Using Fourier transform infrared spectroscopy (FTIR) testing, this invention further proposes an Aging Overall Index (AOI), calculated using a weighted method, as shown in the following formula:

[0037] In the formula, CI, SI, and BI are the carbonyl index, sulfoxide index, and butadiene index, respectively.

[0038] This application uses aromatic sulfoxide (1030 cm⁻¹) -1 ), butadiene (966 cm) -1 The characteristic peak area of ​​the group and the saturated CH bond (1460 cm⁻¹) -1 The aging degree of SBS modified asphalt is quantified by the ratio of the characteristic absorption peak areas. The calculation is performed according to formulas (1) to (3).

[0039]

[0040] Among them: A 1030 A 966 A 1460 and A 1700 They are 1030 cm -1 966 cm -1 1460 cm -1 and 1700 cm -1The peak area corresponds to the surrounding absorbance region; SI, BI, and CI are the sulfoxide index, butadiene index, and carbonyl index, respectively. A higher AOI value indicates a more severe degree of chemical aging of the asphalt after coupled aging. Based on four coupled environmental tests in Hainan, the degree of chemical aging is divided into four levels: Level I (AOI < 1.5, slight aging), Level II (1.5 ≤ AOI < 2.2, moderate aging), Level III (2.2 ≤ AOI < 3.0, severe aging), and Level IV (AOI ≥ 3.0, extreme aging), used to assist in evaluating the chemical aging resistance of asphalt under different climatic micro-regions in Hainan.

[0041] Table 1 AOI Calculation Results for Each Partition

[0042] The results show that: the AOI of the example sample reached 3.68 under the strongest coupling condition of four fields across the entire domain, belonging to Level IV extreme aging; the AOI of Comparative Example 4 was 3.02, and the AOI of Comparative Example 5 was 3.18, both belonging to Level IV extreme aging; the AOI of Comparative Example 1 was 1.77, and the AOI of Comparative Example 2 was 1.97, belonging to Level II moderate aging; the AOI of Comparative Example 3 was 1.39, belonging to Level I slight aging. The AOI ranking of each region was: Example Sample > Comparative Example 5 > Comparative Example 4 > Comparative Example 2 > Comparative Example 1 > Comparative Example 3, which is completely consistent with the severity of the climate in Hainan. This proves that the AOI index proposed in this invention can truly reflect the differences in the intensity of chemical aging of asphalt in different regions of Hainan, and the evaluation results are highly consistent with the severity of the regional climate.

[0043] (2) Comparison of high-temperature rheological properties To further comprehensively characterize the evolution of asphalt's high-temperature rheological properties after coupled aging, this invention proposes a high-temperature rheological aging sensitivity index (HRI), calculated using a weighted method, as shown in the following formula:

[0044] In the formula, G* / sinδ is the rutting factor at 60℃, R is the recovery rate at 3.2kPa, and J is the unrecoverable creep compliance at 3.2kPa.

[0045] A higher HRI value indicates a more severe degree of high-temperature hardening and embrittlement of asphalt after coupled aging. Based on four coupled environmental tests in Hainan, the degree of high-temperature rheological aging was divided into four levels: Level I (HRI < 1.8, slight aging), Level II (1.8 ≤ HRI < 3.0, moderate aging), Level III (3.0 ≤ HRI < 5.0, severe aging), and Level IV (HRI ≥ 5.0, extreme aging). This was used to help evaluate the high-temperature rutting resistance and deformation compatibility of asphalt under different climatic micro-regions in Hainan.

[0046] Table 2 HRI Calculation Results for Each Partition The results showed that the rutting factor of the examples and all comparative examples increased significantly, the recovery rate increased slightly, and the irreversible creep compliance decreased significantly. The order of the increase in rutting factor was: examples > comparative example 5 > comparative example 4 > comparative example 2 > comparative example 1 > comparative example 3, which was basically consistent with the order of climate severity. The HRI of the examples was 2.75, while the HRIs of comparative examples 4 and 5 were 2.69 and 2.80, respectively, both belonging to Level II moderate aging; the HRIs of comparative examples 1 and 2 were 1.94 and 2.08, respectively, belonging to Level II moderate aging; and the HRI of comparative example 3 was 1.47, belonging to Level I slight aging. Although the examples had the strongest four-field coupling conditions, their HRIs were not significantly higher than those of comparative examples 4 and 5, indicating that high-temperature rheological properties have a "hardening ceiling effect" on aging. The comprehensive HRI index can accurately distinguish the degree of asphalt hardening in different zones, and its evaluation sensitivity is significantly higher than that of traditional penetration and softening point.

[0047] (3) Comparison of fatigue performance To further comprehensively characterize the fatigue performance evolution of asphalt after coupled aging, this invention proposes the Fatigue Deterioration Index (FDI), calculated as follows:

[0048] In the formula, N f The fatigue life is measured by linear amplitude scanning (LAS) testing. This is a fatigue factor. This weight applies to all five climate micro-regions of Hainan, ensuring the uniformity of evaluation standards and horizontal comparability.

[0049] A higher FDI value indicates a more severe deterioration in the fatigue performance of asphalt after coupled aging. Based on four coupled environmental tests in Hainan, the degree of fatigue performance deterioration was divided into four levels: Level I (FDI < 2.0, slight deterioration), Level II (2.0 ≤ FDI < 5.0, moderate deterioration), Level III (5.0 ≤ FDI < 10.0, severe deterioration), and Level IV (FDI ≥ 10.0, extreme deterioration), to help evaluate the fatigue cracking resistance of asphalt under different climatic micro-regions in Hainan.

[0050] Table 3 FDI Calculation Results for Each Partition

[0051] The results show that the fatigue life of the examples and comparative examples decreased significantly, while the fatigue factor increased significantly. The FDI of the example was 6.01, belonging to Level III severe deterioration; the FDI of comparative example 5 was 5.01, belonging to Level III severe deterioration; the FDI of comparative example 4 was 4.63, belonging to Level II moderate deterioration; the FDIs of comparative examples 1 and 2 were 2.58 and 2.92 respectively, belonging to Level II moderate deterioration; and the FDI of comparative example 3 was 1.73, belonging to Level I slight deterioration. The FDI ranking was highly consistent with the AOI ranking, indicating a strong correlation between fatigue performance deterioration and the degree of chemical aging. The FDI of the traditional thermo-oxidative aging comparative example was less than 2.0, which deviated greatly from the field conditions. This invention, by coupling aging simulation with the comprehensive FDI index, can accurately identify the fatigue decay law of asphalt in the actual environment of Hainan.

[0052] (4) Evolution of molecular structure Using proton spectrum ( 1 In addition to H NMR testing, this invention proposes a hydrogen spectral comprehensive aging index (HAI), calculated using the following formula:

[0053] In the formula, H b For a specific structure, the hydrogen ratio, H β +H γ This represents the total hydrogen molar content of the aliphatic chains, as shown in Table 4. The calculation formula is as follows: ,

[0054] In the formula, A represents the peak area integral of the corresponding hydrogen in the hydrogen spectrum.

[0055] A higher HAI value indicates a more severe change in the molecular structure of asphalt after coupled aging. Based on the four-field coupled environmental test in Hainan, the degree of aging by hydrogen spectrum is divided into four levels: Level I (HAI < 1.3), Level II (1.3 ≤ HAI < 2.0), Level III (2.0 ≤ HAI < 3.0), and Level IV (HAI ≥ 3.0), which are used to help evaluate the degree of aging and deterioration of asphalt at the molecular level.

[0056] Table 4 1 H-NMR band assignment

[0057] Table 5 HAI Calculation Results for Each Partition

[0058] The results show that: the examples and each comparative example H b The values ​​all increased significantly, H β +H γThe values ​​all decreased to varying degrees. Example 1 had a HAI of 3.48, indicating Level IV extreme aging; Comparative Examples 4 and 5 had HAIs of 3.10 and 3.28 respectively, also indicating Level IV extreme aging; Comparative Example 1 had a HAI of 2.00, indicating the boundary between Level II and Level III aging; Comparative Example 2 had a HAI of 2.15, indicating Level III severe aging; and Comparative Example 3 had a HAI of 1.42, indicating Level II moderate aging. HAI and AOI showed a high positive correlation, verifying the consistency between proton and infrared spectroscopy in evaluating the degree of chemical aging. The HAI of Comparative Example 3 was only 1.42, indicating that the molecular structure of asphalt remained well maintained under salt spray-free and weak radiation conditions. This invention reveals the structural evolution of asphalt under a four-field coupled environment at the molecular level through the HAI index, providing direct evidence for understanding the aging mechanism.

[0059] (5) Proposal of evaluation indicators like Figure 1 The four aging evaluation indicators proposed in this invention—AOI, HRI, FDI, and HAI—can be flexibly combined according to the evaluation purpose and engineering requirements to form a comprehensive weather resistance evaluation in different dimensions. (1) Dual indicator combination: using equal-weighted geometric average (A×B) 1 / 2 Suitable for rapid screening or specific performance-oriented evaluation. Recommended combinations include: AOI+HRI (chemical → high-temperature hardening), AOI+FDI (chemical → fatigue degradation), HRI+FDI (high-temperature + fatigue combined rheological degradation), etc.

[0060] Table 6. Data Table of Dual Indicator Combinations

[0061] The results show that Comparative Example 3 performed best among all the dual-index combinations, belonging to Level I or II; Comparative Examples 1 and 2 belong to Level II or III; and Comparative Examples 4 and 5 belong to Level III or IV. Dual-index combinations are suitable for rapid screening in the material selection stage.

[0062] (2) Three-indicator combination: using equal-weighted geometric mean (A×B×C) 1 / 3 It is suitable for in-depth analysis and multi-dimensional comprehensive evaluation. The most recommended combination is AOI+HRI+FDI, which covers three core dimensions: chemical aging, high-temperature rheological degradation, and fatigue performance decline.

[0063] Table 7. Data Table of Three-Indicator Combination

[0064] The results show that the combined AOI+HRI+FDI value of Comparative Example 3 is 1.52, belonging to Class II; Comparative Example 1 is 2.07, belonging to Class II; Comparative Example 2 is 2.29, belonging to Class III; Comparative Example 4 is 3.34, belonging to Class IV; and Comparative Example 5 is 3.55, belonging to Class IV. The combination of the three indicators covers the three core dimensions of chemical aging, high-temperature rheology, and fatigue performance, and is suitable for in-depth evaluation in the pavement design stage.

[0065] (3) Combination of four indicators: The equal-weighted geometric mean CNI = (AOI × HRI × FDI × HAI) is adopted. 1 / 4 It is defined as the Comprehensive Weathering Index (CNI), which is applicable to comprehensive evaluation and weathering level determination.

[0066] Table 8. Data Table of Four Indicator Combinations

[0067] All the above combinations are based on the unaged state (combination value = 1.0), with higher values ​​indicating more severe aging. Based on the four-field coupled environmental test in Hainan, the following level judgment criteria are uniformly adopted: Level I (Excellent): Combination value < 1.5 Level II (Good): 1.5 ≤ Combination value < 2.2 Level III (Poor): 2.2 ≤ combination value < 3.0 Level IV (Not Applicable): Combination value ≥ 3.0 The weather resistance rating of asphalt in the five climate micro-zones of Hainan is ranked as follows: Comparative Example 3 is better than Comparative Example 1, which is better than Comparative Example 2, which is better than Comparative Example 4, which is better than Comparative Example 5. Specifically, Comparative Example 3 has a CNI of 1.50, falling on the boundary between Level I and II, indicating the best weather resistance in environments without salt spray and with weak radiation, suitable for any road section on the island; Comparative Example 1 has a CNI of 2.05, belonging to Level II (good), suitable for general road sections, but long-term durability needs to be considered in high humidity environments; Comparative Example 2 has a CNI of 2.26, at Level III, where aging is accelerated in high humidity and high salt spray environments, and it is recommended to appropriately increase the dosage of anti-aging modifiers; Comparative Example 4 has a CNI of 3.31, belonging to Level IV (poor), with strong radiation dominating aging, requiring targeted addition of UV stabilizers; Comparative Example 5 has a CNI of 3.52, belonging to Level IV (poor), with the most severe aging caused by the synergistic effect of strong radiation and high salt spray, requiring the simultaneous addition of UV stabilizers and salt corrosion stabilizers.

[0068] As shown in Table 9, in practical engineering applications, the appropriate combination can be selected according to the evaluation purpose: a dual-indicator rapid screening can be used in the material selection stage; a three- or four-indicator comprehensive judgment can be used in the pavement design stage; and a combination containing HAI can be used for microscopic verification in the scientific research mechanism analysis stage. For example, in the quality inspection stage, a dual-indicator rapid screening of the aging level of the asphalt material is first used; then, the measured CNI index of the pavement is superimposed, and the judgment result is comprehensively corrected in combination with the surface crack damage state.

[0069] Table 9 Comparison of Engineering Application Scenarios and Recommended Combinations

[0070] In summary, this invention addresses the extreme service environment of Hainan, characterized by high temperature, high humidity, strong solar radiation, and high salt spray. It employs an indoor method for accelerated aging by simultaneously coupling four factors: temperature, humidity, light, and salt. Combining macroscopic physical properties, dynamic shear rheological characteristics, fatigue performance, and microscopic functional group and molecular structure testing, it proposes four quantitative evaluation indicators: the Comprehensive Aging Index (AOI), the High Temperature Rheological Aging Sensitivity Index (HRI), the Comprehensive Fatigue Performance Deterioration Index (FDI), and the Hydrogen Spectrum Comprehensive Aging Index (HAI). Furthermore, it establishes a comprehensive weather resistance evaluation system with flexible combinations of two, three, and four indicators, enabling accurate determination and classification of asphalt weather resistance. This invention can realistically reproduce the actual aging process of asphalt in Hainan, solving problems such as simulation distortion, single indicators, lack of regional differentiation, and macro-microscopic disconnect in traditional evaluation methods. It boasts advantages such as high evaluation accuracy, strong regional adaptability, clear mechanism, and strong engineering guidance, and can be widely applied to asphalt material selection, quality inspection, pavement durability design, and old road performance evaluation in Hainan.

[0071] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A comprehensive evaluation method for asphalt weather resistance under multi-factor coupled climate aging, characterized in that, Includes the following steps: S1. Perform preliminary thermo-oxidative aging on the asphalt samples. S2. Accelerate the aging of asphalt samples after thermo-oxidative aging by simultaneous coupling of four factors, namely temperature, humidity, solar radiation and salt spray. S3. Perform Fourier transform infrared spectroscopy on the aged asphalt samples. Calculate the carbonyl index, sulfoxide index, and butadiene index based on the test results. Then, obtain the comprehensive aging index (AOI) according to the following formula, thereby obtaining the weather resistance grade of the asphalt sample: In the formula, CI, SI, and BI are the carbonyl index, sulfoxide index, and butadiene index, respectively; aged represents the aged sample, and unaged represents the unaged sample; the larger the AOI value, the deeper the aging degree of the asphalt sample.

2. The comprehensive evaluation method for asphalt weather resistance under multi-factor climate coupled aging as described in claim 1, characterized in that, In step S3, the weather resistance level includes Level I slight aging, with an AOI value < 1.5; Level II moderate aging, with 1.5 ≤ AOI value < 2.2; Level III severe aging, with 2.2 ≤ AOI value < 3.0; and Level IV extreme aging, with an AOI value ≥ 3.

0.

3. The comprehensive evaluation method for asphalt weather resistance under multi-factor climate coupled aging as described in claim 1, characterized in that, Step S3 also includes: conducting rheological property tests on the aged asphalt samples, and then obtaining the high-temperature rheological aging sensitivity index (HRI) according to the following formula: In the formula, G* / sinδ is the rutting factor at 60℃, R is the recovery rate at 3.2kPa, and J is the non-recoverable creep compliance at 3.2kPa; the larger the HRI value, the more severe the high-temperature hardening embrittlement of the asphalt sample after coupled aging.

4. The comprehensive evaluation method for asphalt weather resistance under multi-factor climate coupled aging as described in claim 1, characterized in that, Step S3 also includes: conducting rheological property tests on the aged asphalt samples, and then obtaining the fatigue performance comprehensive deterioration index FDI according to the following formula: In the formula, N f The fatigue life measured by linear amplitude scanning test for rheological property testing. The FDI value represents the fatigue factor; the larger the FDI value, the more severe the fatigue performance degradation of the asphalt sample after coupled aging.

5. The comprehensive evaluation method for asphalt weather resistance under multi-factor climate coupled aging as described in claim 1, characterized in that, Step S3 also includes: performing nuclear magnetic resonance (NMR) 1H NMR spectroscopy on the aged asphalt sample, analyzing the H NMR data, and obtaining the specific structural hydrogen ratio H. b Total hydrogen molar content of aliphatic chains H β +H γ Then, the hydrogen spectrum comprehensive aging index (HAI) is calculated according to the following formula: In the formula, H b For a specific structure, the hydrogen ratio, H β +H γ The HAI value represents the total hydrogen molar content of the aliphatic chain; the higher the HAI value, the more severe the change in molecular structure of the asphalt sample after coupled aging.

6. The comprehensive evaluation method for asphalt weather resistance under multi-factor climate coupled aging according to any one of claims 1-5, characterized in that, Step S3 is followed by: taking at least two of the four quantitative evaluation indicators, namely the High Temperature Rheological Aging Sensitivity Index (HRI), the Fatigue Performance Comprehensive Deterioration Index (FDI), and the Hydrogen Spectrum Comprehensive Aging Index (HAI), and performing an equal-weighted geometric average to obtain the comprehensive weather resistance evaluation level. The final output based on the evaluation results of each indicator includes the weather resistance level, coupled aging and degradation mechanism, degree of influence of each environmental factor, recommended applicable climate zone, and modification and optimization suggestions.

7. The comprehensive evaluation method for asphalt weather resistance under multi-factor coupled climatic aging according to any one of claims 1-5, characterized in that, In step S1, the preliminary thermo-oxidative aging is carried out in an air atmosphere at 163±5℃ for 4-6 hours to simulate the thermo-oxidative aging process of asphalt mixture mixing, paving and compaction. And / or, the asphalt sample to be tested includes base asphalt, SBS modified asphalt, high viscosity modified asphalt, or rubber modified asphalt.

8. The comprehensive evaluation method for asphalt weather resistance under multi-factor climate coupled aging according to any one of claims 1-5, characterized in that, In step S2, the temperature setting range is 60-70℃, the humidity setting range is 70%-90%, and the solar radiation intensity setting range is 700-1100W / m². 2 The salt spray solution is a 0wt%-15wt% NaCl solution; the aging time for the four factors to be synchronously coupled is 12-20 days.

9. The comprehensive evaluation method for asphalt weather resistance under multi-factor climate coupled aging as described in claim 8, characterized in that, The conditions for accelerated aging by the simultaneous coupling of the four factors are: temperature 70℃, humidity 90%, and radiation 1100W / m. 2 Salt concentration 15%, aged for 16 days; Alternatively, the following parameters could be used: temperature 65℃, humidity 85%, radiation 700W / m². 2 Salt concentration 10%, aging for 16 days, corresponding to the humid climate zone in northern Hainan; Alternatively, the following parameters could be used: temperature 65℃, humidity 90%, radiation 900W / m². 2 Salt concentration 10%, aging for 16 days, corresponding to the humid climate zone in eastern Hainan; Alternatively, the following parameters could be used: temperature 60℃, humidity 90%, radiation 700W / m². 2 No salt spray, aged for 16 days, corresponding to the humid climate of the central mountainous region of Hainan; Alternatively, the following parameters could be used: temperature 70℃, humidity 75%, radiation 1100W / m². 2 Salt concentration 15%, aging for 16 days, corresponding to the climate of the southern semi-arid and semi-humid region of Hainan; Alternatively, the following parameters could be used: temperature 70℃, humidity 70%, radiation 1100W / m². 2 The salt concentration is 15%, and the aging time is 16 days, corresponding to the climate of the western semi-arid region of Hainan.

10. An application of the comprehensive evaluation method for asphalt weather resistance under multi-factor climate coupled aging as described in any one of claims 1-9, characterized in that, Used for asphalt material selection, pavement design, quality inspection, or old road assessment; Preferably, when selecting asphalt materials, the evaluation is carried out using the equal-weighted geometric mean of two indicators: AOI+HRI or AOI+FDI. When used for pavement design, the three indicators AOI+HRI+FDI are evaluated using an equal-weighted geometric average. When used for quality inspection, the two indicators are evaluated together with the four indicators of AOI+HRI+FDI+HAI with equal weights using a geometric mean. When used for old road assessment, the three indicators FDI+HRI+CNI are evaluated using an equal-weighted geometric average.

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