Test method for the dosage of high viscosity modifier in dry high viscosity modified drainage asphalt mixture

Abstract

A method for testing the dosage of high-viscosity modifiers in dry-process high-viscosity modified drainage asphalt mixtures includes: 1) testing the raw materials used to produce the high-viscosity asphalt mixture. 2) preparing the high-viscosity asphalt mixture in a mixing plant using a dry process, with random sampling. 3) preparing ideal high-viscosity modified asphalt using a high-speed shear instrument, followed by preparing the high-viscosity asphalt mixture using a small asphalt mixing mill. 4) preparing test specimens. 5) using surface-enhanced Raman spectroscopy to examine the asphalt film area on the aggregate surface and obtain the Raman characteristic peak of the asphalt on the aggregate surface. 6) using a confocal Raman-AFM linkage system to obtain the modulus parameters at the Raman characteristic peak. 7) comparing the differences in the modulus parameters to calculate the actual dosage of the high-viscosity modifier in the dry-process high-viscosity asphalt mixture. This method addresses the current problem of being unable to accurately assess the dosage of high-viscosity modifiers and mixing uniformity in dry-process high-viscosity asphalt mixtures.

Description

Technical Field

[0001] The invention belongs to the technical field of road engineering, and in particular relates to a method for testing the dosage of a high-viscosity modifier in a dry-process high-viscosity modified drainage asphalt mixture. Background Art

[0002] Drainage-resistant asphalt pavement is internationally recognized for its high safety and low noise levels, earning it the title of "Top Service Functional Pavement," hence its widespread use. Drainage-resistant asphalt pavement utilizes a porous asphalt mixture, an open-graded, high-void ratio. Due to the low proportion of fine aggregate, contact between the aggregates is primarily point-to-point, and the large voids make the asphalt binder more susceptible to water erosion and thermal oxidative aging. Therefore, the asphalt binder must possess excellent adhesion and aging resistance, forming a thicker asphalt film, necessitating the use of high-viscosity modified asphalt.

[0003] High-viscosity modified asphalt can be divided into finished high-viscosity modified asphalt and dry-process high-viscosity modified asphalt based on the modifier addition method. Dry-process high-viscosity modified asphalt refers to the direct addition of high-viscosity modifiers during the asphalt mixture mixing process. This can avoid aging and segregation of the finished high-viscosity modified asphalt during production, storage, and transportation. It is convenient for storage, allowing for flexible production scheduling, suitable for long-distance transportation, and convenient for small-scale construction. However, the current construction of dry-process high-viscosity asphalt relies on the manual addition of high-viscosity modifiers, making it difficult to accurately determine the actual dosage of high-viscosity modifiers in the prepared high-viscosity modified asphalt mixture and the mixing uniformity, resulting in the design performance of drainage asphalt pavements failing to meet expectations. Therefore, accurately understanding the dosage of high-viscosity modifiers in dry-process high-viscosity modified asphalt mixtures will effectively guide the production of high-viscosity asphalt mixtures and have a positive impact on ensuring the construction quality of drainage asphalt pavements.

[0004] Ideally, high-viscosity modified asphalt should have a uniform distribution of the high-viscosity modifier throughout the asphalt and form a stable structure with the asphalt. In drainage asphalt mixtures, however, the high-viscosity asphalt adheres to the aggregate surface, ensuring good bonding between the aggregates. Therefore, by comparing the properties of the asphalt on the aggregate surface of high-viscosity asphalt mixtures prepared under ideal conditions with those of actual high-viscosity asphalt mixtures, we can gain insights into the dosage and mixing uniformity of the high-viscosity modifier in the produced high-viscosity asphalt mixtures. The challenge lies in conducting rapid in-situ testing of the asphalt on the aggregate surface in high-viscosity asphalt mixtures produced in a mixing plant.

[0005] Raman spectroscopy and imaging techniques, with their ability to obtain the "fingerprint" characteristics of material composition and their rapid, non-destructive nature, are particularly suitable for in-situ detection and analysis of interface microstructural evolution, making them an excellent candidate for studying the local chemical, mechanical, and crystallographic properties of complex materials. Furthermore, Raman spectroscopy can be combined with AFM to obtain micromechanical parameters of material microstructures. This provides a powerful tool for analyzing the dosage of high-viscosity modifiers in high-viscosity asphalt mixtures. The present invention, based on the combination of Raman spectroscopy and AFM, provides a method for accurately evaluating the dosage of high-viscosity modifiers in dry-process high-viscosity asphalt mixtures. Summary of the Invention

[0006] The technical problem to be solved by the present invention is that the present invention provides a method for testing the dosage of high-viscosity modifier in dry high-viscosity modified drainage asphalt mixture, which solves the problem that the current dry high-viscosity asphalt mixture cannot accurately evaluate the dosage of high-viscosity modifier and mixing uniformity.

[0007] To achieve the above object, the technical solution adopted by the present invention is:

[0008] The dry process high viscosity modified drainage asphalt mixture high viscosity modifier dosage test method includes the following steps:

[0009] The first step is to produce raw materials for high viscosity asphalt mixture:

[0010] Asphalt, aggregate, mineral powder, and high viscosity agent are tested;

[0011] In the second step, the mixing plant prepares high-viscosity asphalt mixture according to the dry method, and uses the random sampling method to take the produced high-viscosity asphalt mixture loose material for use;

[0012] In the third step, a high-viscosity modified asphalt is prepared indoors using a high-speed shear instrument under ideal conditions, and then a small asphalt mixture mixer is used to prepare a high-viscosity asphalt mixture for use;

[0013] Step 4: Randomly select 3 to 5 aggregates from the high-viscosity asphalt mixture produced in the mixing plant and the high-viscosity asphalt mixture prepared indoors. The aggregate nominal particle size ranges from 5 to 15 mm. Use a cutting machine to cut samples no larger than 10 mm × 10 mm × 5 mm. Use epoxy resin to encapsulate the samples and polish them for testing.

[0014] In the fifth step, surface-enhanced Raman spectroscopy (SERS) was used to detect the asphalt film on the aggregate surface using a "flower-shaped" nanosilver sol as the substrate and a 532nm wavelength laser. The asphalt Raman characteristic peaks of the aggregate surface obtained in the fourth step were then compared with those of the high-viscosity asphalt mixture produced in the mixing plant and prepared indoors.

[0015] In the sixth step, the AFM atomic force microscope in the confocal Raman-AFM linkage system is used to perform in-situ loading on the Raman characteristic peak of the asphalt on the surface of the high-viscosity asphalt mixture aggregate produced in the mixing plant and prepared indoors, and the modulus parameters at the Raman characteristic peak are obtained. After the test is completed, the 95% confidence interval of the modulus parameter results of the asphalt on the surface of the high-viscosity asphalt mixture produced in the mixing plant and prepared indoors is selected and the average value is taken;

[0016] The seventh step is to calculate the actual dosage of high viscosity modifier in dry high viscosity asphalt mixture. The calculation formula is:

[0017]

[0018] in, It is the average modulus at the asphalt Raman characteristic peak on the aggregate surface of high-viscosity asphalt mixture produced by the mixing plant. It is the average modulus at the asphalt Raman characteristic peak on the aggregate surface of high-viscosity asphalt mixture prepared indoors.

[0019] As a further improvement of the present invention, in the second step, the high-viscosity asphalt mixture produced by the mixing plant is randomly sampled according to the asphalt mixture sampling method specified in T0701-2011 of JTGE20-2011 in the test procedures for highway asphalt and asphalt mixture.

[0020] As a further improvement of the present invention, in the third step, the steps of preparing high-viscosity modified asphalt under ideal conditions indoors using a high-speed shear instrument are as follows:

[0021] (1) Use an electronic balance to weigh a certain mass of base asphalt or SBS modified asphalt sample, place it in a sample container, and heat it to 180°C in an oven;

[0022] (2) Weigh a certain amount of high-viscosity additive in proportion, add it to the asphalt and stir it evenly with a glass rod;

[0023] (3) Use a shearing machine to shear the asphalt at a rate of 5000 r / min ± 200 r / min for 30 min, and maintain the temperature at 180°C ± 10°C during the shearing process;

[0024] (4) Turn off the shearing machine and place the prepared high-viscosity additive-modified asphalt in an oven at 180°C ± 5°C for 30 minutes. After completion, conduct relevant tests immediately.

[0025] As a further improvement of the present invention, in the fourth step, the cut sample surface is finely and effectively polished. The cut sample is sealed and formed with epoxy resin and a silicone mold to obtain a resin sample that is easy to polish. The resin sample is simply polished with a grinder to expose the aggregate surface. The aggregate surface is then further finely polished with metallographic sandpaper to obtain a surface with a flatness that meets the requirements. Finally, the sample is placed in anhydrous ethanol or acetone and ultrasonically cleaned.

[0026] As a further improvement of the present invention, in the fourth step, the fineness is required to be gradually increased during the grinding process, that is, grinding is carried out in sequence with 100, 200, 400, 800, and 1000 mesh metallographic sandpaper, and polishing is carried out with a polishing agent.

[0027] As a further improvement of the present invention, in the fifth step, the preparation method of the "flower-shaped" nanosilver sol is as follows:

[0028] (1) Weigh 1.7 g of silver nitrate and dissolve it in 10 ml of ultrapure water (1 mol / L), weigh 0.1 g of polyvinylpyrrolidone and dissolve it in 9.9 g of ultrapure water, and weigh 0.1761 g of ascorbic acid and dissolve it in 10 ml of ultrapure water (0.1 mol / L).

[0029] (2) Place 10 ml of deionized water, 0.2 ml of silver nitrate solution, and 2 ml of 1% polyvinyl pyrrolidone solution in a beaker in that order;

[0030] (3) Stir the mixture under a constant temperature magnetic stirrer. After stirring evenly, quickly add 1 ml of ascorbic acid solution and stir at 600 r / min for 15 min.

[0031] (4) Centrifuge at 8000 rpm for 10 min to remove impurities, wash three times with ethanol and ultrapure water, and centrifuge again;

[0032] (5) Add 10 ml of ultrapure water and use ultrasonic vibration to disperse it evenly to obtain a "flower-shaped" nanosilver sol. Before Raman spectroscopy, use Raman spectroscopy 520 cm -1 The semiconductor silicon wafer was used as a standard. The test sample and the prepared nanosilver sol were pasted together in a 1:1 ratio and then placed on the movable platform of an inverted microscope connected to a Raman spectrometer to collect Raman spectral data. For each sample, 10 different points in the asphalt film on the aggregate surface were selected to collect Raman spectra, and the average value was calculated. The acquisition parameters were an integration time of 10 s and a wavenumber range of 500-2000 cm -1 .

[0033] As a further improvement of the present invention, in the sixth step, the method for obtaining the Raman characteristic peak of asphalt on the surface of the high-viscosity asphalt mixture aggregate produced in the mixing plant and prepared indoors is to use Raman mapping technology for imaging, and the specific steps are:

[0034] The sample is fixed on the displacement platform of the Raman test system, with the vertical direction fixed and imaging performed only in the horizontal direction. First, use the microscope objective lens to adjust the sample to a clear field of view under white light, circle the observation area, then turn off the white light, turn on the laser, and use Raman Mapping technology to image.

[0035] As a further improvement of the present invention, the imaging parameters of the Raman Mapping technology are set as follows:

[0036] The laser is an Nd:YAG laser with a λ=532nm and a power of 75mW. The number of grating grooves is 1200. By rotating the grating tower, the Raman spectrum detection range covers 0 to 4000cm-1, with a resolution of 1cm-1. The CCD is cooled at -60°C. The microscope objective is 10× (Zeiss, EC, Epiplan-Neofluar, Germany), and the laser spot diameter is 25μm. The confocal microstructure is connected to the laser and spectrometer via two optical fibers: an excitation fiber and a collection fiber, each with an inner diameter of 100μm. The Raman system is calibrated before use. Silicon is used for laser wavelength calibration, and its spectrum is verified using MappingStream. The HR scanning step was 1 μm, the specimen was exposed for 0.2 s, single-point accumulation was 1 time, and the laser power was 5.16 mW. After obtaining the area represented by the Raman characteristic peak, the AFM atomic force microscope was used to perform in-situ loading on the characteristic peak area. The AFM mechanical property quantification module AFM-QNM was used to quantitatively characterize the microscale mechanical properties of the selected test area, and the DMT model in contact mechanics was used to fit and analyze the reduced Young's modulus of the sample.

[0037] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0038] This method considers a high-viscosity asphalt mixture prepared indoors as an ideal high-viscosity asphalt mixture with 100% high-viscosity modifier content. It then compares this with a dry-process high-viscosity asphalt mixture produced in a mixing plant. Using Raman-AFM in-situ testing, the mechanical parameters of the asphalt film on the aggregate surface of both the indoor and actual production mixtures are rapidly and accurately determined. This comparative analysis accurately determines the actual content of the high-viscosity modifier in the dry-process high-viscosity asphalt mixture, thereby providing better guidance for the production and construction of dry-process high-viscosity asphalt mixtures. The method features high detection accuracy, simple sample preparation, strong operability, and ease of implementation. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Raman spectrum of asphalt on aggregate surface. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0041] This embodiment provides a method for testing the dosage of a high-viscosity modifier in a dry high-viscosity modified drainage asphalt mixture, comprising the following steps:

[0042] The first step is to test the raw materials used to produce high-viscosity asphalt mixtures: asphalt, aggregate, mineral powder, high viscosity agent, etc.

[0043] In the second step, the mixing plant produces one pot of high-viscosity asphalt mixture (2 tons) according to the composition of high-viscosity asphalt mixture materials. According to the asphalt mixture sampling method of the "Test Procedure for Highway Asphalt and Asphalt Mixture" (JTG E20-2011) T0701-2011, the high-viscosity asphalt mixture produced by the mixing plant is randomly collected for use.

[0044] The third step is to first prepare high-viscosity modified asphalt under ideal conditions indoors using a high-speed shear instrument. The steps are as follows: (1) Use an electronic balance to weigh a certain mass of base asphalt or SBS modified asphalt sample and place it in a sample container, and heat it to 180℃ in an oven; (2) Weigh a certain mass of high-viscosity additive in proportion, add it to the asphalt and stir it evenly with a glass rod; (3) Use a shearing machine to shear the asphalt at a rate of 5000r / min±200r / min for 30 minutes, and maintain the temperature at 180℃±10℃ during the shearing process; (4) Turn off the shearing machine, place the prepared high-viscosity additive modified asphalt in a 180℃±5℃ oven for development for 30 minutes, and conduct relevant tests immediately after completion.

[0045] Then, a small asphalt mixture mixer is used to prepare a high-viscosity asphalt mixture under ideal conditions. The specific steps include: first, the aggregate is put into the mixing pot and stirred for 90 seconds, then the prepared high-viscosity asphalt is added and stirred for 90 seconds, and finally, the mineral powder is added and stirred for 90 seconds to obtain the high-viscosity asphalt mixture under the ideal condition.

[0046] Preferably, the mixer is set to 180°C and preheated for 1-2 hours before mixing. The aggregate, mineral powder, and asphalt must all be heated in an oven for a certain period of time. The aggregate and mineral powder are heated to 180°C for 4 hours. Different heating temperatures are selected for different asphalt types. For 70# base asphalt, the heating temperature is 150°C, and for SBS modified asphalt, the heating temperature is 175°C. The heating time for both asphalts is 2 hours.

[0047] In the fourth step, 3 to 5 aggregates were randomly selected from the high-viscosity asphalt mixture produced at the mixing plant and the high-viscosity asphalt mixture prepared indoors. The aggregates had a nominal particle size range of 5 to 15 mm. Samples no larger than 10 mm x 10 mm x 5 mm were cut using a cutter. The cut samples were sealed and molded using epoxy resin and a silicone mold to produce resin samples that were easily polished. The resin samples were briefly polished using a grinder to expose the aggregate surface. The aggregate surface was then further finely polished using metallographic sandpaper to achieve a surface that met the required flatness. The polishing process required a progressively finer grade, using 100, 200, 400, 800, and 1000 grit metallographic sandpaper in that order, followed by polishing with a polishing compound. Finally, the samples were ultrasonically cleaned in anhydrous ethanol or acetone to obtain the samples used for the subsequent Raman spectroscopy-AFM experiments.

[0048] The fifth step is to be able to perform Raman spectroscopy-AFM testing on the asphalt on the aggregate surface, the prepared sample needs to be placed on a nanosilver substrate. Therefore, the nanosilver substrate is first prepared. The preparation method of the nanosilver sol is as follows: (1) Weigh 1.7g of silver nitrate and dissolve it in 10ml of ultrapure water (1mol / L). Weigh 0.1g of polyvinyl pyrrolidone and dissolve it in 9.9g of ultrapure water. Weigh 0.1761g of ascorbic acid and dissolve it in 10ml of ultrapure water (0.1mol / L). (2) Take 10ml of deionized water, 0.2ml of silver nitrate solution, and 2ml of polyvinyl pyrrolidone (1%) in a beaker in sequence. (3) Stir the mixture under a constant temperature magnetic stirrer. After stirring evenly, quickly add 1ml of ascorbic acid solution and stir for 15min (600r / min). (4) Centrifuge (8000r / min, 10min) to wash and remove impurities. Wash three times with ethanol and ultrapure water respectively and centrifuge. (5) Add 10 ml of ultrapure water and use ultrasonic vibration to disperse it evenly to obtain a "flower-shaped" nanosilver sol. Then, use a semiconductor silicon wafer (520 cm -1 ) calibration, the test sample and the prepared nanosilver sol were pasted together in a 1:1 ratio and then placed on the movable platform of an inverted microscope connected to the Raman spectrometer to collect Raman spectral data. For each sample, Raman spectra were collected at 10 different points in the asphalt film on the aggregate surface, and the average value was calculated. The acquisition parameters were an integration time of 10 seconds and a wavenumber range of 500 to 2000 cm -1 . Raman spectrum of asphalt on aggregate surface Figure 1 shown.

[0049] The sixth step is to use Raman mapping technology to image the surface asphalt of the aggregate using the obtained Raman spectrum. This technique identifies the region of the Raman characteristic peaks of the asphalt on the surface of the high-viscosity asphalt mixture produced in the mixing plant and prepared indoors. The specific steps are as follows: The sample is fixed to the displacement platform of the Raman testing system, with the vertical direction fixed and imaging performed only in the horizontal direction. First, under white light, the microscope objective is used to adjust the sample to a clear field of view and circle the observation area. Then, the white light is turned off, the laser is turned on, and the Raman mapping technique is used for imaging. The parameters are as follows: the laser is an Nd:YAG laser (λ = 532nm, power 75mW), the number of grating grooves is 1200, and by rotating the grating tower, the Raman spectrum detection range covers 0 to 4000cm⁻¹, with a resolution of 1cm⁻¹. The CCD is cooled at -60°C. The microscope objective was 10× (Zeiss, EC, Epiplan-Neofluar, Germany), and the laser spot diameter was 25 μm. The confocal microscope was connected to the laser and spectrometer via two optical fibers (the excitation and collection fibers both had an inner diameter of 100 μm). The Raman system was calibrated before use. Silicon was used for laser wavelength calibration and its spectrum was used for verification. Mapping Stream HR scanning was performed with a 1 μm step, 0.2 s exposure time, 1 single-point accumulation, and a laser power of 5.16 mW.

[0050] After obtaining the area represented by the Raman characteristic peak, the characteristic peak area was loaded in situ using an atomic force microscope (AFM). The AFM mechanical properties quantification module (AFM-QNM) was used to quantitatively characterize the microscale mechanical properties of the selected test area. The DMT model in contact mechanics was used to fit and analyze the reduced Young's modulus of the sample. The calculation formulas are shown in Equations (1) and (2).

[0051]

[0052] Where, F tip is the force applied to the cantilever tip; F adh is the adhesion force between the probe and the sample; R is the tip radius; d is the sample deformation; E* is the Young's modulus of the sample.

[0053]

[0054] Where: v s 、v tip are the Poisson's ratios of the reference sample and the probe, respectively; E tip 、E s are the moduli of the probe and the reference sample, respectively.

[0055] The seventh step is to calculate the actual dosage of high viscosity modifier in dry high viscosity asphalt mixture. The calculation formula is:

[0056]

[0057] in, It is the average modulus at the asphalt Raman characteristic peak on the aggregate surface of high-viscosity asphalt mixture produced by the mixing plant. It is the average modulus at the asphalt Raman characteristic peak on the aggregate surface of high-viscosity asphalt mixture prepared indoors.

[0058] This embodiment uses Raman-AFM atomic force microscopy technology to test the Young's modulus of asphalt on the aggregate surface, and proposes a method and quantitative index for accurately testing the dosage of high-viscosity modifier in dry high-viscosity asphalt mixture, which makes up for the shortcomings of the existing technology.

[0059] The above description is merely a preferred embodiment of the present invention and does not constitute any other form of limitation to the present invention. Any modification or equivalent variation based on the technical essence of the present invention shall still fall within the scope of protection claimed by the present invention.

Claims

1. The dry process high viscosity modified drainage asphalt mixture high viscosity modifier dosage test method is characterized by: The following steps are involved: The first step is to produce raw materials for high viscosity asphalt mixture: Asphalt, aggregate, mineral powder, and high viscosity agent are tested; In the second step, the mixing plant prepares high-viscosity asphalt mixture according to the dry method, and uses the random sampling method to take the produced high-viscosity asphalt mixture loose material for use; In the third step, a high-viscosity modified asphalt is prepared indoors using a high-speed shear instrument under ideal conditions, and then a small asphalt mixture mixer is used to prepare a high-viscosity asphalt mixture for use; Step 4: Randomly select 3 to 5 aggregates from the high-viscosity asphalt mixture produced in the mixing plant and the high-viscosity asphalt mixture prepared indoors. The aggregate nominal particle size ranges from 5 to 15 mm. Use a cutting machine to cut samples no larger than 10 mm × 10 mm × 5 mm. Use epoxy resin to encapsulate the samples and polish them for testing. In the fifth step, surface-enhanced Raman spectroscopy (SERS) was used to examine the asphalt film on the aggregate surface using a "flower-shaped" nanosilver sol as a substrate and a 532nm laser. The characteristic Raman peaks of the asphalt on the aggregate surface obtained in the fourth step were then compared with those of the high-viscosity asphalt mixture produced in the mixing plant and prepared indoors. In the sixth step, the AFM atomic force microscope in the confocal Raman-AFM linkage system is used to perform in-situ loading on the Raman characteristic peak of the asphalt on the surface of the high-viscosity asphalt mixture aggregate produced in the mixing plant and prepared indoors, and the modulus parameters at the Raman characteristic peak are obtained. After the test is completed, the 95% confidence interval of the modulus parameter results of the asphalt on the surface of the high-viscosity asphalt mixture produced in the mixing plant and prepared indoors is selected and the average value is taken; The seventh step is to calculate the actual dosage of high viscosity modifier in dry high viscosity asphalt mixture. The calculation formula is: ； in, is the average modulus of the asphalt Raman characteristic peak on the surface of the high-viscosity asphalt mixture produced by the mixing plant, It is the average modulus at the asphalt Raman characteristic peak on the aggregate surface of high-viscosity asphalt mixture prepared indoors.

2. The method for testing the dosage of high-viscosity modifier for dry high-viscosity modified drainage asphalt mixture according to claim 1, characterized in that: In the second step, random sampling of the high-viscosity asphalt mixture produced by the mixing plant was carried out according to the asphalt mixture sampling method specified in T0701-2011 of JTG E20-2011 in the Test Procedure for Highway Asphalt and Asphalt Mixtures.

3. The method for testing the dosage of high-viscosity modifier for dry high-viscosity modified drainage asphalt mixture according to claim 1, characterized in that: In the third step, the steps for preparing high-viscosity modified asphalt under ideal conditions using a high-speed shear instrument are as follows: (1) Use an electronic balance to weigh a certain mass of base asphalt or SBS modified asphalt sample, place it in a sample container, and heat it to 180°C in an oven; (2) Weigh a certain amount of high-viscosity additive in proportion, add it to the asphalt and stir it evenly with a glass rod; (3) Use a shearing machine to shear the asphalt at a rate of 5000 r / min ± 200 r / min for 30 min, and maintain the temperature at 180℃ ± 10℃ during the shearing process; (4) Turn off the shearing machine and place the prepared high-viscosity additive-modified asphalt in an oven at 180℃±5℃ for 30 minutes. After completion, conduct relevant tests immediately.

4. The method for testing the dosage of a high-viscosity modifier for a dry high-viscosity modified drainage asphalt mixture according to claim 1, wherein: In the fourth step, for the cut sample, the surface of the cut sample needs to be finely and effectively polished, and the cut sample is sealed and formed with epoxy resin and silicone mold to obtain a resin sample that is easy to polish. The resin sample is simply polished with a grinder to expose the aggregate surface, and then the aggregate surface is further finely polished with metallographic sandpaper to obtain a surface with flatness that meets the requirements. Finally, the sample is placed in anhydrous ethanol or acetone and cleaned with ultrasonic waves.

5. The method for testing the dosage of high-viscosity modifier for dry high-viscosity modified drainage asphalt mixture according to claim 4, characterized in that: In the fourth step, the fineness is required to be increased step by step during the grinding process, that is, use 100, 200, 400, 800, and 1000 mesh metallographic sandpaper in sequence, and polish with polishing agent.

6. The method for testing the dosage of high-viscosity modifier for dry high-viscosity modified drainage asphalt mixture according to claim 1, characterized in that: In the fifth step, the preparation method of the "flower-shaped" nanosilver sol is as follows: (1) Weigh 1.7 g of silver nitrate and dissolve it in 10 ml of ultrapure water (1 mol / L), weigh 0.1 g of polyvinyl pyrrolidone and dissolve it in 9.9 g of ultrapure water, and weigh 0.1761 g of ascorbic acid and dissolve it in 10 ml of ultrapure water (0.1 mol / L). (2) Take 10 ml of deionized water, 0.2 ml of silver nitrate solution, and 2 ml of 1% polyvinyl pyrrolidone solution in a beaker in that order; (3) Stir the mixture under a constant temperature magnetic stirrer. After stirring evenly, quickly add 1 ml of ascorbic acid solution and stir at 600 r / min for 15 min. (4) Centrifuge at 8000 rpm for 10 min to remove impurities, wash three times with ethanol and ultrapure water, and centrifuge again; (5) Add 10 ml of ultrapure water and use ultrasonic vibration to disperse it evenly to obtain a "flower-shaped" nanosilver sol. Before Raman spectroscopy detection, use Raman spectroscopy 520 cm -1 The semiconductor silicon wafer was used as the standard. The test sample and the prepared nanosilver sol were pasted together in a 1:1 ratio and then placed on the movable platform of an inverted microscope connected to a Raman spectrometer to collect Raman spectral data. For each sample, 10 different points in the asphalt film on the aggregate surface were selected to collect Raman spectra, and the average value was calculated. The acquisition parameters were an integration time of 10 s and a wavenumber range of 500-2000 cm -1 .

7. The method for testing the dosage of high-viscosity modifier for dry high-viscosity modified drainage asphalt mixture according to claim 1, characterized in that: In the sixth step, the Raman characteristic peaks of asphalt on the surface of the high-viscosity asphalt mixture aggregate produced in the mixing plant and prepared indoors are obtained by imaging using Raman mapping technology. The specific steps are as follows: The sample is fixed on the displacement platform of the Raman test system, with the vertical direction fixed and imaging performed only in the horizontal direction. First, use the microscope objective lens to adjust the sample to a clear field of view under white light, circle the observation area, then turn off the white light, turn on the laser, and use Raman Mapping technology to image.

8. The method for testing the dosage of high-viscosity modifier for dry high-viscosity modified drainage asphalt mixture according to claim 7, characterized in that: The imaging parameters of Raman Mapping technology are set as follows: The laser is a Nd:YAG laser with λ=532nm, a power of 75mW, and 1200 grating grooves. By rotating the grating tower, the Raman spectrum detection range covers 0~4000cm-1, with a resolution of 1cm-1. The CCD cooling temperature is -60℃. The microscope objective is 10× (Zeiss, EC, Epiplan-Neofluar, Germany). The laser spot diameter is 25μm. The confocal microstructure is connected to the laser and spectrometer through two optical fibers, one for excitation and the other for collection, and both have an inner diameter of 100μm. The Raman system is calibrated before use. Silicon is used for laser wavelength calibration, and its spectrum is used for verification. Mapping The StreamHR scanning step is 1μm, the specimen is exposed for 0.2s, single point accumulation is 1 time, and the laser power is 5.16mW. After obtaining the area represented by the Raman characteristic peak, the AFM atomic force microscope is used to perform in-situ loading on the characteristic peak area. The AFM mechanical property quantification module AFM-QNM is used to quantitatively characterize the microscale mechanical properties of the selected test area, and the DMT model in contact mechanics is used to fit and analyze the reduced Young's modulus of the sample.

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