A salt spray-ultraviolet cycle coupling test system and an application method thereof

Abstract

This invention discloses a salt spray-ultraviolet (UV) cyclic coupling test system and its application method, belonging to the field of road engineering technology. The system consists of a salt spray chamber, a UV irradiation chamber, an environmental parameter control module, and a cross-scale testing unit. The salt spray chamber is equipped with glass nozzles, a disperser, a slot, a temperature sensor, and a humidity sensor; the solution circulation pipeline is configured with a conductivity monitoring module. The UV irradiation chamber is equipped with a broadband UVA / UVB light source. The environmental parameter control module integrates a PID temperature control system, a humidity sensor, and a programmable cyclic function, supporting alternating salt spray-UV cyclic programs. The cross-scale testing unit is compatible with dynamic shear rheometers and four-point bending fatigue devices capable of macroscopic mechanical testing, as well as interfaces for microscopic molecular dynamics simulation software, enabling cross-scale correlation analysis of asphalt material properties. This invention solves the technical problems of isolated environmental parameters and distorted synergistic effects in traditional equipment and testing methods.

Description

Technical Field

[0001] This invention belongs to the field of road engineering technology, specifically a salt spray-ultraviolet cyclic coupling test system and its application method. Background Technology

[0002] Asphalt material durability testing equipment is mainly divided into two categories: single-environment simulation and multi-factor step-by-step testing. Among them, the salt spray test chamber simulates the marine atmospheric corrosion environment through salt solution spraying, offering advantages such as low cost and ease of operation, and is currently the most widely used salt corrosion testing device. The ultraviolet aging chamber uses a specific wavelength light source to simulate solar radiation, effectively assessing photo-oxidative damage to materials, but it cannot reproduce the real climatic conditions of alternating salt spray and ultraviolet radiation. While temperature and humidity cycling test equipment can simulate alternating hot and humid environments, it lacks characterization of the synergistic mechanism between salt crystallization-dissolution phase transition and photochemical aging. Therefore, existing testing equipment is mostly limited to single or step-by-step environmental parameter control, making it difficult to accurately reflect the multi-factor coupled erosion scenarios in coastal areas.

[0003] In practical engineering, asphalt pavements are exposed to a multi-physical field coupling environment for extended periods, including salt spray deposition, ultraviolet radiation, and alternating temperature and humidity. This results in a significant nonlinear synergistic effect in performance degradation. For example, the expansion stress from sodium sulfate crystallization and the molecular chain breakage induced by ultraviolet radiation jointly accelerate interfacial debonding, while high-temperature environments further exacerbate the damage accumulation rate. Conventional single-factor testing equipment, due to the isolated control of environmental parameters, cannot capture such multi-factor interactions, leading to significant discrepancies between laboratory data and field service behavior, severely limiting the accuracy of durability design.

[0004] To improve the realism of testing, existing technologies attempt to simulate multiple factors through equipment combinations, such as using a salt spray chamber and a UV chamber in series. However, such solutions suffer from parameter coupling mismatch and cannot achieve precise synchronous control of temperature and humidity gradients and erosion cycles. Furthermore, traditional salt spray nozzles are easily corroded by high-concentration sulfate solutions, and spray uniformity decreases significantly over test duration, making it difficult to meet the requirements for long-term stable testing. Therefore, there is an urgent need to develop an integrated, high-precision multi-factor coupled testing system to overcome the technical bottlenecks of existing equipment in terms of environmental simulation realism, parameter control accuracy, and long-term stability. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a salt spray-ultraviolet cyclic coupling test system and its application method, which is used to simulate the deterioration process of asphalt materials under coastal high-salt, high-temperature, high-humidity and strong ultraviolet environments, in order to solve the technical problems of insufficient environmental simulation realism, parameter control accuracy and long-term stability of existing equipment.

[0006] To achieve the above objectives, this invention discloses a salt spray-ultraviolet cyclic coupling test system, comprising a salt spray chamber, an ultraviolet irradiation chamber, an environmental parameter control module, and a cross-scale testing unit, wherein:

[0007] The salt spray chamber is equipped with borosilicate glass nozzles, conical titanium alloy dispersers, slots, a temperature sensor, and a humidity sensor. The slots are arranged in strips near the bottom of the salt spray chamber, with multiple slots parallel to each other and located at the midpoint of the chamber's length. Dispersers are symmetrically arranged on both sides of each slot. A temperature sensor and a humidity sensor are respectively mounted on the base of each disperser. Glass nozzles are located next to each disperser. The solution circulation pipeline is equipped with a conductivity monitoring module. The spray volume adjustment range is 0.5-3.0 mL / (h·cm). 2 The salt solution concentration is controlled with an accuracy of ±0.3%. A storage chamber is set at the bottom of the salt spray chamber, and a heating tube is installed in the storage chamber.

[0008] The ultraviolet irradiation chamber is equipped with a broadband UVA / UVB light source with a wavelength of 315-400 nm and an irradiation intensity adjustment range of 0-450 W / m². 2 Light intensity fluctuation rate ≤2%;

[0009] The environmental parameter control module and the cross-scale testing unit are located on the control panel of the salt spray chamber;

[0010] The environmental parameter control module integrates a PID temperature control system, a humidity sensor, and a programmable loop function to control the temperature and humidity of the salt spray chamber and support an alternating salt spray-UV cycle program. The temperature control system controls the heating power of the heating element, with a temperature range of 5-60℃ and an accuracy of ±0.2℃. The humidity sensor has a humidity control range of 30-98% RH and an error of ±2%.

[0011] The cross-scale testing unit is compatible with dynamic shear rheometers and four-point bending fatigue equipment that can perform macroscopic mechanical tests, as well as interfaces for software that can perform microscopic molecular dynamics simulations, enabling cross-scale correlation analysis of asphalt material properties.

[0012] The salt spray chamber is equipped with a precision stepper motor to control the spray volume of the glass nozzles, and the unit of spray volume is mL / (h·cm). 2 The linear adjustment error of the spray volume is ≤ ±0.1 mL / (h·cm). 2 The nozzle has a salt spray corrosion resistance life of ≥2000 hours.

[0013] The ultraviolet irradiation chamber is equipped with light intensity feedback modules at the top and bottom to calibrate the irradiation intensity in real time, and the spectral distribution matches the natural ultraviolet radiation by ≥95%.

[0014] The environmental parameter control module supports coupled programming of multi-gradient temperature ΔT=5℃ and multi-gradient humidity ΔRH=10%, with a cycle setting range of 1-999 hours.

[0015] This invention also discloses an application method for a salt spray-ultraviolet cyclic coupling test system, which includes the following steps:

[0016] Step 1: Install the asphalt or asphalt mixture sample into the salt spray chamber slot, inject the Na2SO4 salt solution into the storage chamber, the concentration of the salt solution is 3%-7%, set the environmental parameters of the salt spray chamber: temperature 20-30℃ for asphalt samples, temperature 30-60℃ for asphalt mixture samples, humidity 70-98% RH. Start the salt spraying program, so that the glass nozzle sprays the asphalt sample. During the spraying process, the environmental parameter control module controls the temperature and humidity in the salt spray chamber according to the data fed back by the temperature sensor and humidity sensor.

[0017] Step 2: After the salt spray corrosion has reached the set time, transfer the sample to an ultraviolet irradiation chamber and set the irradiation intensity to 300-450 W / m². 2 The wavelength combination UVA:UVB = 3:1 was used to perform the ultraviolet aging procedure;

[0018] Step 3: Repeat steps 1-2. The cumulative erosion time for asphalt samples is 10-30 days, and the cumulative erosion time for asphalt mixture samples is 3-9 days. Record environmental parameters and sample performance data simultaneously.

[0019] Step 4: Test the fatigue factor of asphalt using a dynamic shear rheometer with a multi-scale testing unit. and continuous damage life N f50 The flexural stiffness modulus decay curve of asphalt mixture was obtained by four-point bending test.

[0020] Step 5: Based on molecular dynamics simulations, construct a four-component asphalt-SiO2 interface model and quantitatively analyze SO4. 2- The influence of charge shielding, competitive adsorption of water molecules, and ultraviolet oxidation on adhesion energy.

[0021] Preferably, in step 1, the salt solution concentration is dynamically adjusted by a conductivity monitoring module, with a concentration deviation ≤ ±0.3%.

[0022] Preferably, in step 3, the salt spray-ultraviolet cycle is programmed according to a day-night alternation mode, with a single cycle duration of 24 hours, including 12 hours of salt spraying and 12 hours of ultraviolet irradiation.

[0023] Preferably, the molecular dynamics simulation in step 5 uses a PCFF+ force field, is embedded in a 5% Na2SO4 solution environment, is set at a temperature of 20-60℃, and has an ultraviolet photon energy perturbation of 3.94 eV.

[0024] Preferably, the cross-scale test unit data interface supports MedeA and LAMMPS software to realize automatic correlation analysis of macro and micro data.

[0025] Preferably, the four-point bending fatigue device of the cross-scale testing unit has a loading frequency of 10Hz, a strain control mode of 800με, and a test temperature of 30℃.

[0026] The present invention has the following beneficial effects:

[0027] 1. The salt spray-ultraviolet multi-factor synchronous coupling test system of the present invention accurately reproduces the diurnal erosion characteristics of the coastal environment through an alternating cycle program of 12 hours of salt spray + 12 hours of ultraviolet light, overcoming the technical bottleneck of isolated environmental parameters and distortion of synergistic effect in traditional equipment;

[0028] 2. A corrosion-resistant atomization system, consisting of a borosilicate nozzle, a titanium alloy disperser, and a conductivity monitoring module, is used to monitor the salt solution in real time, ensuring that the salt solution concentration deviation is ≤±0.3%, thus making the salt solution concentration stable over a long period of time and significantly improving the reliability and repeatability of the test data.

[0029] 3. Through cross-scale testing units, macroscopic mechanics and microscopic molecular simulation can be linked for analysis, systematically revealing the synergistic deterioration mechanism of sulfate crystallization expansion, ultraviolet molecular chain breakage and hygrothermal migration, providing multi-dimensional theoretical support for the design of high-durability asphalt pavements. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the salt spray chamber of the present invention;

[0031] Figure 2 This is a schematic diagram of the structure of the ultraviolet irradiation box of the present invention;

[0032] In the diagram: 1. Salt spray chamber, 2. Disperser, 3. Conductivity monitoring module, 4. Glass nozzle, 5. Humidity sensor, 6. Card slot, 7. Temperature sensor, 8. Control box, 9. Ultraviolet irradiation chamber, 10. Light intensity feedback module. Detailed Implementation

[0033] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0034] See Figure 1 and Figure 2This invention discloses a salt spray-ultraviolet cyclic coupling test system, comprising a salt spray chamber 1, an ultraviolet irradiation chamber 9, an environmental parameter control module, and a cross-scale testing unit, wherein:

[0035] The salt spray chamber 1 is equipped with borosilicate glass nozzles 4, conical titanium alloy dispersers 2, slots 6, temperature sensors 7, and humidity sensors 5. The slots 6 are arranged in a strip shape near the bottom of the salt spray chamber, with multiple slots 6 parallel to each other and located at the middle of the length of the salt spray chamber 1. Dispersers 2 are symmetrically arranged on both sides of the slots 6. Temperature sensors 7 and humidity sensors 5 are respectively installed on the bases of the two dispersers 2. Glass nozzles 4 are located next to each disperser 2. The solution circulation pipeline is equipped with a conductivity monitoring module 3. The salt spray chamber 1 is equipped with a control box 8, and the spray volume adjustment range is 0.5-3.0 mL / (h·cm). 2 The salt solution concentration is controlled with an accuracy of ±0.3%. A liquid storage chamber is provided at the bottom of the salt spray chamber 1, and a heating tube is installed inside the liquid storage chamber.

[0036] The ultraviolet irradiation chamber 9 is equipped with a broadband UVA / UVB light source with a wavelength of 315-400 nm and an irradiation intensity adjustment range of 0-450 W / m². 2 Light intensity fluctuation rate ≤2%;

[0037] The environmental parameter control module and the cross-scale testing unit are located on the control panel of the salt spray chamber 1;

[0038] The environmental parameter control module integrates a PID temperature control system, a humidity sensor 5, and a programmable loop function to control the temperature and humidity of the salt spray chamber 1 and support an alternating salt spray-UV cycle program. The temperature control system has a temperature range of 5-60℃ with an accuracy of ±0.2℃; the humidity sensor 5 has a humidity control range of 30-98% RH with an error of ±2%.

[0039] The cross-scale testing unit is compatible with dynamic shear rheometers and four-point bending fatigue equipment that can perform macroscopic mechanical tests, as well as interfaces for software that can perform microscopic molecular dynamics simulations, enabling cross-scale correlation analysis of asphalt material properties.

[0040] The salt spray chamber 1 is equipped with a precision stepper motor to control the spray volume of the glass nozzle 4. The spray volume refers to the volume of salt solution deposited on a unit sample area per unit time, and the unit is mL / (h·cm). 2 The linear adjustment error of the spray volume is ≤ ±0.1 mL / (h·cm). 2 The nozzle has a salt spray corrosion resistance life of ≥2000 hours.

[0041] The top and bottom of the ultraviolet irradiation chamber 9 are equipped with light intensity feedback modules 10 to calibrate the irradiation intensity in real time, and the spectral distribution matches the natural ultraviolet radiation by ≥95%.

[0042] The environmental parameter control module supports coupled programming of multi-gradient temperature ΔT=5℃ and multi-gradient humidity ΔRH=10%, with a cycle setting range of 1-999 hours.

[0043] It should be noted that in this application:

[0044] "Asphalt sample" refers to an asphalt binder film sample made of base asphalt, without aggregate, used for mechanical property testing of binder layers such as dynamic shear rheology (DSR).

[0045] "Asphalt mixture specimen" refers to a small beam specimen formed by mixing asphalt with aggregates (crushed stone, sand, mineral powder, etc.) and used for mechanical property testing of the mixture layer, such as four-point bending fatigue.

[0046] Example 1

[0047] The application method of the salt spray-ultraviolet cyclic coupling test system of the present invention is as follows:

[0048] Step 1: Cut the asphalt mixture sample into standard test plates of 400mm×300mm×75mm, and then refine them into small beam specimens of 380±5mm×63±6mm×50±6mm using a CNC water-cooled cutting system. After cleaning the surface with deionized water, install the specimens in the slot 6 of the salt spray chamber, ensuring that the distance between adjacent specimens is ≥10mm. For the asphalt sample, heat the fluid dynamic matrix asphalt to above the phase change point and then coat it evenly on the silicon-based template. Control the thickness of the film to a standard thickness of 1.0±0.1mm using a precision scraper. After the sample is cooled to room temperature, it is cured at 5℃ in deionized water medium for 15 minutes to stabilize the microstructure. After two ultrasonic cleanings, a reference sample that meets the requirements of DSR testing is obtained.

[0049] Step 2: Prepare a 5% Na2SO4 solution with a purity ≥99.5%, and inject the Na2SO4 salt solution into the storage chamber; set the environmental parameters of the salt spray chamber 1: temperature 30℃ (asphalt) / 60℃ (asphalt mixture), humidity 75%RH, spray volume 1.5 mL / (h·cm²), start the salt spray program, and continue for 12 hours. During the spraying, the solution concentration is monitored in real time by the conductivity feedback from the conductivity monitoring module 3 to ensure that the salt solution concentration deviation is ≤±0.3% and to ensure the uniformity of atomization;

[0050] Step 3: After the salt spray corrosion reaches the set time, transfer the specimen to the ultraviolet irradiation chamber 9, set the irradiation intensity to 450W / m², the wavelength combination to UVA:UVB=3:1, and the temperature to be the same as that of the salt spray chamber 1 in Step 2. Perform a 12-hour ultraviolet aging program, and calibrate the light intensity feedback module every 30 minutes to ensure that the spectral distribution is consistent with natural ultraviolet light.

[0051] Step 4: Repeat steps 2-3. The cumulative erosion time for asphalt is 30 days; the cumulative erosion time for asphalt mixture is 9 days. Record the specimen mass change, surface morphology and environmental parameters after each cycle (24 hours). Mass change and surface morphology are recorded under environmental parameters of temperature fluctuation ±0.2℃ and humidity error ±2% RH.

[0052] Step 5, macroscopic mechanical tests were conducted using a multi-scale test unit. (1) Dynamic shear rheological test: Bohlin ADS rheometer was used, with strain amplitude set to 10%, frequency to 10Hz, and temperature to 30℃, to test the fatigue factor of asphalt. and continuous damage life N f50 (2) Four-point bending fatigue test: According to the "Test Procedure for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG3410-2025), the strain control mode was set to 800με and the loading frequency was 10Hz, and the bending tensile stiffness modulus decay curve was measured.

[0053] Step 6: Microscopic molecular dynamics simulation was performed using a cross-scale testing unit: An interface model of the four components of asphalt (asphaltene, resin, aromatics, saturated components) with SiO2 aggregate was constructed based on the MedeA platform, embedding a 5% Na2SO4 solution environment; the temperature was set to 60℃ and the ultraviolet photon energy perturbation to 3.94 eV, and the changes in adhesion energy and SO42- were calculated. 2- Ion diffusion coefficient.

[0054] 1. Verification of multi-factor coupled damage

[0055] Table 1. Comparison of damage indices between multi-factor coupling and single-factor coupling in Example 1

[0056]

[0057] Conclusion: Coupling effect leads to the index characterizing the deterioration of asphalt fatigue performance. The increase was 2.05 times that of a single factor, N f50 The lifespan degradation rate is 1.23 times that of a single factor, and the interfacial adhesion energy decreases by 12.1%.

[0058] 2. Cross-scale data correlation in coupled experiments

[0059] Table 2 Example 1 SO4 2- Cross-scale correlation analysis of migration and macroscopic modulus decay

[0060]

[0061] Conclusion: Molecular-scale SO4 2- Migration and macroscopic modulus decay show a strong linear correlation, verifying the reliability of the multi-field coupled damage model.

[0062] Example 2

[0063] The application method of the salt spray-ultraviolet cyclic coupling test system of the present invention is as follows:

[0064] Step 1: Cut the asphalt mixture sample into standard test plates of 400mm×300mm×75mm, and then refine them into small beam specimens of 380±5mm×63±6mm×50±6mm using a CNC water-cooled cutting system. After cleaning the surface with deionized water, install the specimens in the slot 6 of the salt spray chamber, ensuring that the distance between adjacent specimens is ≥10mm. For the asphalt sample, heat the fluid dynamic matrix asphalt to above the phase change point and then coat it evenly on the silicon-based template. Control the thickness of the film to a standard thickness of 1.0±0.1mm using a precision scraper. After the sample is cooled to room temperature, it is cured at 5℃ in deionized water medium for 15 minutes to stabilize the microstructure. After two ultrasonic cleanings, a reference sample that meets the requirements of DSR testing is obtained.

[0065] Step 2: Prepare a 3% Na2SO4 solution with a purity ≥99.5%, and inject the Na2SO4 salt solution into the storage chamber; set the environmental parameters of the salt spray chamber 1: temperature 20℃ (asphalt) / 30℃ (asphalt mixture), humidity 70%RH, spray volume 1.5 mL / (h·cm²), start the salt spray program, and continue for 12 hours. During the spraying, the conductivity monitoring module 3 is used to monitor the solution concentration in real time to ensure that the salt solution concentration deviation is ≤±0.3% and to ensure the uniformity of atomization;

[0066] Step 3: After the salt spray corrosion has reached the set time, transfer the specimen to the ultraviolet irradiation chamber 9 and set the irradiation intensity to 300 W / m². 2 The wavelength combination is UVA:UVB=3:1, the temperature is the same as that of salt spray chamber 1 in step 2, and a 12-hour ultraviolet aging program is performed. The light intensity feedback module is calibrated every 30 minutes to ensure that the spectral distribution is consistent with natural ultraviolet light.

[0067] Step 4: Repeat steps 2-3. The cumulative erosion time for asphalt is 10 days; the cumulative erosion time for asphalt mixture is 3 days. Record the specimen mass change, surface morphology and environmental parameters after each cycle (24 hours). The mass change and surface morphology are recorded under environmental parameters of temperature fluctuation ±0.2℃ and humidity error ±2% RH.

[0068] Step 5, macroscopic mechanical tests were conducted using a multi-scale test unit. (1) Dynamic shear rheological test: Bohlin ADS rheometer was used, with strain amplitude set to 10%, frequency to 10Hz, and temperature to 30℃, to test the fatigue factor of asphalt. and continuous damage life N f50(2) Four-point bending fatigue test: According to the "Test Procedure for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG3410-2025), the strain control mode was set to 800με and the loading frequency was 10Hz, and the bending tensile stiffness modulus decay curve was measured.

[0069] Step 6: Microscopic molecular dynamics simulation was performed using a cross-scale testing unit: An interface model of the four components of asphalt (asphaltene, resin, aromatics, saturated components) with SiO2 aggregate was constructed based on the MedeA platform, embedding a 3% Na2SO4 solution environment; the temperature was set to 30℃, and the ultraviolet photon energy perturbation was 3.94 eV. The changes in adhesion energy and SO42- were calculated. 2- Ion diffusion coefficient.

[0070] 1. Verification of multi-factor coupled damage

[0071] Table 3 Comparison of damage indices between multi-factor coupling and single-factor coupling in Example 2

[0072]

[0073] Conclusion: Coupling effect leads to the index characterizing the deterioration of asphalt fatigue performance. The increase was 1.73 times that of a single factor, N f50 The lifespan degradation rate is 1.71 times that of a single factor, and the interfacial adhesion energy decreases by 16.3%.

[0074] 2. Cross-scale data correlation in coupled experiments

[0075] Table 4 Example 2 SO4 2- Cross-scale correlation analysis of migration and macroscopic modulus decay

[0076]

[0077] Conclusion: Molecular-scale SO4 2- Migration and macroscopic modulus decay show a strong linear correlation, verifying the reliability of the multi-field coupled damage model.

[0078] Example 3

[0079] The application method of the salt spray-ultraviolet cyclic coupling test system of the present invention is as follows:

[0080] Step 1: Cut the asphalt mixture sample into standard test plates of 400mm×300mm×75mm, and then refine them into small beam specimens of 380±5mm×63±6mm×50±6mm using a CNC water-cooled cutting system. After cleaning the surface with deionized water, install the specimens in the slot 6 of the salt spray chamber, ensuring that the distance between adjacent specimens is ≥10mm. For the asphalt sample, heat the fluid dynamic matrix asphalt to above the phase change point and then coat it evenly on the silicon-based template. Control the thickness of the film to a standard thickness of 1.0±0.1mm using a precision scraper. After the sample is cooled to room temperature, it is cured at 5℃ in deionized water medium for 15 minutes to stabilize the microstructure. After two ultrasonic cleanings, a reference sample that meets the requirements of DSR testing is obtained.

[0081] Step 2: Prepare a 7% Na2SO4 solution with a purity ≥99.5%, and inject the Na2SO4 salt solution into the storage chamber; set the environmental parameters of the salt spray chamber 1: temperature 25℃ (asphalt) / 45℃ (asphalt mixture), humidity 98%RH, spray volume 1.5 mL / (h·cm²), start the salt spray program, and continue for 12 hours. During the spraying, the conductivity monitoring module 3 is used to monitor the solution concentration in real time to ensure that the salt solution concentration deviation is ≤±0.3% and to ensure the uniformity of atomization;

[0082] Step 3: After the salt spray corrosion has reached the set time, transfer the specimen to the ultraviolet irradiation chamber 9 and set the irradiation intensity to 400 W / m². 2 The wavelength combination is UVA:UVB=3:1, the temperature is the same as that of salt spray chamber 1 in step 2, and a 12-hour ultraviolet aging program is performed. The light intensity feedback module is calibrated every 30 minutes to ensure that the spectral distribution is consistent with natural ultraviolet light.

[0083] Step 4: Repeat steps 2-3. The cumulative erosion time for asphalt is 20 days; the cumulative erosion time for asphalt mixture is 6 days. Record the specimen mass change, surface morphology and environmental parameters after each cycle (24 hours). Mass change and surface morphology are recorded under environmental parameters of temperature fluctuation ±0.2℃ and humidity error ±2% RH.

[0084] Step 5, macroscopic mechanical tests were conducted using a multi-scale test unit. (1) Dynamic shear rheological test: Bohlin ADS rheometer was used, with strain amplitude set to 10%, frequency to 10Hz, and temperature to 30℃, to test the fatigue factor of asphalt. and continuous damage life N f50 (2) Four-point bending fatigue test: According to the "Test Procedure for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG3410-2025), the strain control mode was set to 800με and the loading frequency was 10Hz, and the bending tensile stiffness modulus decay curve was measured.

[0085] Step 6: Microscopic molecular dynamics simulation was performed using a cross-scale testing unit: An interface model of the four components of asphalt (asphaltene, resin, aromatics, saturated components) and SiO2 aggregate was constructed based on the MedeA platform, embedding a 7% Na2SO4 solution environment; the temperature was set to 45℃ and the ultraviolet photon energy perturbation to 3.94 eV, and the changes in adhesion energy and SO42- were calculated. 2- Ion diffusion coefficient.

[0086] 1. Verification of multi-factor coupled damage

[0087] Table 5 Comparison of damage indices between multi-factor coupling and single-factor coupling in Example 3

[0088]

[0089] Conclusion: Coupling effect leads to the index characterizing the deterioration of asphalt fatigue performance. The increase was 1.88 times that of a single factor, N f50 The lifespan degradation rate is 1.15 times that of a single factor, and the interfacial adhesion energy decreases by 18.2%.

[0090] 2. Cross-scale data correlation in coupled experiments

[0091] Table 6 Example 3 SO4 2- Cross-scale correlation analysis of migration and macroscopic modulus decay

[0092]

[0093] Conclusion: Molecular-scale SO4 2- Migration and macroscopic modulus decay show a strong linear correlation, verifying the reliability of the multi-field coupled damage model.

[0094] The above embodiments demonstrate that this system can accurately simulate the coupled environment of multiple factors along the coast, and the salt spray-UV alternating cycle program significantly improves the realism of the experiment. Compared with single salt spray erosion, salt spray-UV coupling further exacerbates the degradation of fatigue-related properties of materials, manifested in an increase in rheological parameters of approximately 1.7–2.1 times and a decrease in fatigue life of approximately 1.1–1.7 times; the attenuation of interfacial adhesion energy is reduced by approximately 12%–18% under coupled conditions compared to single salt spray; and the cross-scale fitting results show that the macroscopic performance degradation is related to SO4. 2- There is a strong linear correlation between diffusion and changes in interfacial hydrogen bonds (R0). 2 (Approximately 0.87–0.93).

[0095] The embodiments of the present invention are merely preferred examples and are not intended to limit the scope of protection thereof; therefore, all equivalent modifications based on the structure, shape and principle of the present invention should be included within the scope of protection of the present invention.

Claims

1. A salt spray-ultraviolet cyclic coupling test system, characterized in that: It consists of a salt spray chamber, an ultraviolet irradiation chamber, an environmental parameter control module, and a multi-scale testing unit, wherein: The salt spray chamber is equipped with borosilicate glass nozzles, titanium alloy dispersers, slots, temperature sensors, and humidity sensors. The slots are arranged in strips near the bottom of the salt spray chamber, with multiple slots parallel to each other and located in the middle of the length of the salt spray chamber. Dispersers are symmetrically arranged on both sides of the slots. Temperature sensors and humidity sensors are respectively installed on the base of the two dispersers. Glass nozzles are arranged next to each disperser. The solution circulation pipeline is equipped with a conductivity monitoring module. A liquid storage chamber is set at the bottom of the salt spray chamber, and a heating tube is installed in the liquid storage chamber. The ultraviolet irradiation chamber is equipped with a broadband UVA / UVB light source with a wavelength of 315-400 nm and an irradiation intensity adjustment range of 0-450 W / m². 2 Light intensity fluctuation rate ≤2%; The environmental parameter control module and the cross-scale testing unit are located on the control panel of the salt spray chamber; The environmental parameter control module integrates a PID temperature control system, a humidity sensor, and a programming loop function to control the temperature and humidity inside the salt spray chamber and support an alternating salt spray-ultraviolet cycle program. The cross-scale testing unit is compatible with dynamic shear rheometers, four-point bending fatigue equipment, and molecular dynamics simulation software interfaces.

2. The salt spray-ultraviolet cyclic coupling test system according to claim 1, characterized in that, The salt spray chamber is equipped with a precision stepper motor to control the spray volume of the glass nozzles, and the unit of spray volume is mL / (h·cm). 2 The linear adjustment error of the spray volume is ≤ ±0.1 mL / (h·cm). 2 The nozzle has a salt spray corrosion resistance life of ≥2000 hours.

3. The salt spray-ultraviolet cyclic coupling test system according to claim 1, characterized in that, The ultraviolet irradiation chamber is equipped with light intensity feedback modules at the top and bottom to calibrate the irradiation intensity in real time, and the spectral distribution matches the natural ultraviolet radiation by ≥95%.

4. The salt spray-ultraviolet cyclic coupling test system according to claim 1, characterized in that, The environmental parameter control module supports coupled programming of multi-gradient temperature ΔT=5℃ and multi-gradient humidity ΔRH=10%, with a cycle setting range of 1-999 hours.

5. An application method of a salt spray-ultraviolet cyclic coupling test system, characterized in that, The system described in any one of claims 1-4 includes the following steps: Step 1: Install the asphalt sample in the salt spray chamber slot, inject the Na2SO4 salt solution into the storage chamber, the concentration of the salt solution is 3%-7%, set the environmental parameters of the salt spray chamber: temperature 20-30℃ for asphalt sample, temperature 30-60℃ for asphalt mixture sample, humidity 70-98% RH, start the salt spray program, and spray the asphalt sample with the glass nozzle. During the spraying process, the environmental parameter control module controls the temperature and humidity in the salt spray chamber according to the data fed back by the temperature sensor and humidity sensor. Step 2: After the salt spray corrosion has reached the set time, transfer the sample to an ultraviolet irradiation chamber and set the irradiation intensity to 300-450 W / m². 2 The wavelength combination of UVA:UVB is 2:1 to 4:1, and an ultraviolet aging procedure is performed. Step 3: Repeat steps 1-2. The cumulative erosion time for asphalt samples is 10-30 days, and the cumulative erosion time for asphalt mixture samples is 3-9 days. Record environmental parameters and sample performance data simultaneously. Step 4: Test the fatigue factor of asphalt using a dynamic shear rheometer with a multi-scale testing unit. and continuous damage life N f50 The flexural stiffness modulus decay curve of the mixture was obtained by a four-point bending test. Step 5: Based on molecular dynamics simulations, construct a four-component asphalt-SiO2 interface model and quantitatively analyze SO4. 2- The influence of charge shielding, competitive adsorption of water molecules, and ultraviolet oxidation on adhesion energy.

6. The application method of the salt spray-ultraviolet cyclic coupling test system according to claim 5, characterized in that, In step 1, the salt solution concentration is dynamically adjusted by the conductivity monitoring module, with a concentration deviation of ≤ ±0.3%.

7. The application method of the salt spray-ultraviolet cyclic coupling test system according to claim 5, characterized in that, In step 3, the salt spray-ultraviolet cycle is programmed according to a day-night alternation pattern, with a single cycle lasting 24 hours, including 12 hours of salt spraying and 12 hours of ultraviolet irradiation.

8. The application method of the salt spray-ultraviolet cyclic coupling test system according to claim 5, characterized in that, The molecular dynamics simulation in step 5 uses a PCFF+ force field, embedded in a 5% Na2SO4 solution environment, with a temperature gradient set to 20-60℃ and an ultraviolet photon energy perturbation of 3.94 eV.

9. The application method of the salt spray-ultraviolet cyclic coupling test system according to claim 5, characterized in that, The cross-scale test unit data interface supports MedeA and LAMMPS software.

10. The application method of the salt spray-ultraviolet cyclic coupling test system according to claim 5, characterized in that, The four-point bending fatigue device of the cross-scale testing unit has a loading frequency of 10Hz, a strain control mode of 800με, and a test temperature of 30℃.

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