Method for testing asphalt surface topography and mechanical properties based on atomic force microscopy

Abstract

The present application relates to a kind of asphalt surface topography and mechanical property test method based on atomic force microscope, comprising the following steps: classification heating asphalt sample and preparing test sample, so that different kinds of modified asphalt can obtain typical stable, uniform nanoscale phase structure brownish yellow film test area;Atomic force microscope eyepiece and the ring circle water mark of brownish yellow film area are used to determine test path and test area, and the surface topography and mechanical property test are carried out;Nanoscope Analysis software is used to carry out qualitative and quantitative analysis on the surface topography roughness, adhesion value and Young's modulus value of test pattern respectively.Compared with prior art, the test method of the present application realizes that various modified asphalts can present stable, uniform nanoscale phase structure and test area by optimizing asphalt sample preparation method, realizes high-precision rapid test, and simultaneously quickly discriminates the modification effect of polymer additive material.

Description

Technical Field

[0001] This invention relates to the field of road traffic engineering, and in particular to a method for testing the surface morphology and mechanical properties of asphalt based on atomic force microscopy. Background Technology

[0002] The addition of polymeric asphalt admixtures will significantly increase the viscosity of asphalt. The increased viscosity of asphalt can significantly enhance the bonding force between acidic asphalt and alkaline aggregates, thereby enhancing the road performance and service life of asphalt pavements.

[0003] With the development of society and economy, on the one hand, damage to asphalt pavement and decline in road performance will affect the comfort and travel experience of drivers; on the other hand, high-grade asphalt pavement such as long-life, durable and ecologically functional asphalt pavement urgently needs to be developed and promoted. Therefore, various polymer modified asphalts with relatively high viscosity have received widespread attention and research in the industry.

[0004] In addition, my country has a vast territory and significant climate differences between the north and south. In order to cope with various special climatic environments, the application of polymeric asphalt admixtures with directional reinforcement properties in high-grade asphalt highways is becoming more and more widespread.

[0005] With the implementation of construction concepts such as "Safe and High-Quality Projects for a Century" and "Low-Carbon Transportation," high-viscosity modified asphalt and rubber powder modified asphalt have become the standard asphalt for high-quality asphalt pavement.

[0006] Existing atomic force microscopy (AFM) testing techniques and analytical theories for asphalt materials are derived from and developed on base asphalt with relatively low viscosity: 1) They are partially applicable to styrene-butadiene-styrene triblock copolymer (SBS) modified asphalt with small viscosity increases, or aged base asphalt; 2) They are extremely difficult to use for analyzing high-viscosity modified asphalt and rubber powder modified asphalt with large viscosity increases.

[0007] Currently, the main method for preparing AFM asphalt samples is to heat them and then allow them to flow naturally on a glass slide. This is primarily because this method can eliminate the changes in macroscopic and microscopic structure caused by cutting (friction scratches, frictional heat), thus preserving the macroscopic and microscopic structural characteristics of the asphalt after thermosetting.

[0008] However, on the one hand, asphalt is prone to aging in the high-temperature thin film state, and modified asphalt with relatively high viscosity at the current sample preparation temperature is not easy to level; on the other hand, the addition of polymeric modifiers will seriously affect the formation of uniform and stable nanoscale phase structure of asphalt materials. At present, the viscosity of the base asphalt is low and it can be leveled, but the internal polymeric components crystallize and protrude, and there are still hundreds of nanometer-level undulations, which makes it impossible for atomic force microscopy to perform micron-level continuous acquisition on the surface, resulting in large data dispersion; while various modified asphalts have high viscosity and are not easy to level, and the protrusions of the modifier crystals are even more serious. Among them, the viscosity of high-viscosity modified asphalt is too high, and the rubber powder particles in rubber powder modified asphalt are relatively large and difficult to decompose, both of which make it difficult to prepare a smooth test area with high data reproducibility. Summary of the Invention

[0009] The purpose of this invention is to overcome the shortcomings of the existing technology by providing a testing method for the surface morphology and mechanical properties of asphalt based on atomic force microscopy. By optimizing the asphalt sample preparation method, various modified asphalts can exhibit stable and uniform nanoscale phase structures and test areas, thereby achieving high-precision rapid testing technology. At the same time, it can quickly identify the modification effect of polymer admixtures, providing nanoscale technical support and theoretical guidance for enhancing the mechanical, durability and other properties of relatively high viscosity modified asphalt.

[0010] The objective of this invention can be achieved through the following technical solutions:

[0011] The purpose of this invention is to provide a method for testing the surface morphology and mechanical properties of asphalt based on atomic force microscopy, comprising the following steps:

[0012] S1. Based on the macroscopic high-temperature flow characteristics of asphalt, the micron-level coagulation characteristics of polymer chains, and the formation characteristics of stable and uniform nanoscale phase structures, asphalt samples were classified and heated to prepare test specimens. The resulting asphalt specimens showed a chestnut yellow film test area, which included ring-shaped water ripples.

[0013] S2. Using the eyepiece of an atomic force microscope and the ring-shaped water ripples in the chestnut yellow film area, determine the test path and test area;

[0014] S3. Surface morphology and mechanical properties are tested using an atomic force microscope to obtain test patterns. The test patterns include a set of patterns of surface roughness, a set of patterns of adhesion force values, and a set of patterns of Young's modulus values. Qualitative and quantitative analysis of the test patterns is performed using Nanoscope Analysis software to obtain surface roughness, adhesion force values, and Young's modulus values.

[0015] Further, step S1 includes the following sub-steps:

[0016] S11. Heat the asphalt sample to make it flowable, stir for 3-5 turns, and obtain the stirred asphalt.

[0017] S12. Insert a glass rod into the stirred asphalt obtained in step S11, 1-5 cm deep, and place a drop on a glass slide to obtain a glass slide with added asphalt.

[0018] S13. The glass slide with added asphalt obtained in step S12 is tilted and placed in a high-temperature oven for heat treatment. The asphalt melt flows freely at the interface of the glass slide. Depending on the chain length and content of polymer chains in different regions inside the melt, turbulence and laminar flow will occur under the action of heat and gravity, and heat-treated asphalt is obtained.

[0019] S14. Cool the heat-treated asphalt obtained in step S13 to obtain an asphalt sample. The obtained asphalt sample includes a chestnut yellow film area, which includes ring-shaped watermarks.

[0020] Further, the heat treatment conditions in step S13 are as follows: the heat treatment temperature of the base asphalt is 130-140℃, and the free flow time is 1-3 minutes; the heat treatment temperature of the rubber powder modified asphalt is 145-155℃, and the free flow time is 3-4 minutes; the heat treatment temperature of the styrene-butadiene-styrene triblock copolymer modified asphalt is 165-175℃, and the free flow time is 4-6 minutes; the heat treatment temperature of the high viscosity modified asphalt is 185-195℃, and the free flow time is at least 8 minutes, until a chestnut yellow film area appears at the tail of the glass slide.

[0021] Further, in step S12, a glass rod is inserted 1-5 cm into the stirred asphalt obtained in step S11, and a drop is placed on the upper 1 / 5 of the glass slide; a drop is placed on the glass slide, and 0.1-1.0 g of asphalt is added to the glass slide according to the different types of asphalt. The specific asphalt classifications are as follows: base asphalt 0.1-0.3 g; rubber powder modified asphalt 0.2-0.4 g; styrene-butadiene-styrene triblock copolymer modified asphalt 0.4-0.6 g; high viscosity modified asphalt 0.5-1.0 g.

[0022] Furthermore, in step S13, the glass slide with the asphalt dripped on is placed in a high-temperature oven with the upper part facing upward at a 75-85° angle.

[0023] Furthermore, the cooling conditions described in step S14 are as follows: cooling temperature 20-25℃, cooling time 24h.

[0024] Further, step S2 includes the following sub-steps:

[0025] S21. When the probe under the cantilever beam descends to near the designed distance, the edge of the asphalt sample is located using the physical eyepiece of an atomic microscope.

[0026] S22. Move from the edge of the asphalt sample toward the asphalt sample to find the annular watermark;

[0027] S23. Place the virtual image of the triangular cantilever beam in the field of view of the physical eyepiece inside the ring of water ripples, and continue to lower the probe to the designed test distance;

[0028] S24. The recommended test path is from the inside to the outside of the ring water ripple to ensure that the test starting point is located at the highest point of the nanoscale, so as to prevent the probe under the cantilever beam from touching or getting too close to the surface of the asphalt sample in the scanning test direction, which would cause the test morphology or mechanical index map to show point-like pitting that cannot truly reflect the nanoscale information of the asphalt surface, or even cause a small amount of asphalt to adhere to the probe and affect the test of subsequent samples.

[0029] S25. The test area is the region near the annular water ripples. Further, in step S22, the sample is moved 0.05-0.2 cm from the edge towards the asphalt sample.

[0030] Furthermore, step S3 includes the following sub-steps:

[0031] S31. The elastic coefficient of the quasi-cantilever on the atomic force microscope probe was determined through a standard calibration experiment.

[0032] S32. Using the PeakForce QNM mode of an atomic force microscope, atlases of surface morphology roughness, adhesion force values, and Young's modulus values ​​of the test area of ​​the asphalt sample are collected.

[0033] S33. Using the Nanoscope Analysis software built into the atomic force microscope, perform qualitative and quantitative analysis of the graphs and data of the atlas of surface morphology roughness, adhesion force values ​​and Young's modulus values ​​to obtain the surface morphology roughness, adhesion force values ​​and Young's modulus values.

[0034] Furthermore, the atlas described in step S3 includes 2D and 3D graphs.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1) The method for testing the surface morphology and mechanical properties of asphalt based on atomic force microscopy provided by this invention controls the sampling amount, the height of the drop on the glass slide, the tilt angle of the glass slide, and the heat treatment temperature during sample preparation. This allows the asphalt melt after high-temperature heat treatment to flow freely at the interface of the glass slide. Based on the chain length and content of polymer chains in different regions inside the melt, turbulent and laminar flow phenomena will occur under the action of heat and gravity. The more viscous part (sol-gel type asphalt: with higher content of admixture polymer chains, asphaltenes, and resins) will agglomerate in the middle of the glass slide due to turbulent unevenness. Other parts (sol-gel type asphalt: with higher content of saturated and aromatic components) will flow and level in the lower part of the glass slide through laminar flow. This method can achieve a stable and uniform nanoscale phase structure and test area for various modified asphalts.

[0037] 2) The method for testing the surface morphology and mechanical properties of asphalt based on atomic force microscopy provided by this invention addresses the difficulty in achieving high data reproducibility in the leveling test area of ​​modified asphalt. By optimizing the sample preparation method and based on the high-temperature flow characteristics of different types of asphalt, asphalt samples are heated and prepared, enabling all types of modified asphalt to exhibit stable and uniform nanoscale phase structures and test areas. This helps eliminate data fluctuations in the nanoscale indicators of modified asphalt, improves data reproducibility, and achieves high-precision rapid testing. It provides nanoscale technical support and theoretical guidance for enhancing the mechanical and durability properties of relatively high-viscosity modified asphalt. At the same time, it can quickly identify the modification effect of polymer admixtures, thereby developing more efficient and low-carbon polymer admixtures. Attached Figure Description

[0038] Figure 1 A schematic diagram of the ring-shaped watermarks in the method for testing the surface morphology and mechanical properties of asphalt based on atomic force microscopy provided in Example 1. Detailed Implementation

[0039] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0040] Any preparation methods, materials, structures, or composition ratios not explicitly described in this technical solution are considered common technical features disclosed in the prior art.

[0041] In Examples 1-6, the base asphalt was Ssangyong 70# base asphalt from South Korea, imported by Qingdao Rishi Jitong Asphalt Co., Ltd., and its quality met the relevant requirements in the "Technical Specification for Construction of Highway Asphalt Pavement" (JTGF40-2004).

[0042] SBS modified asphalt is a plant-mixed, self-made modified asphalt. The formula consists of Korean Ssangyong 70# base asphalt plus 4.5% linear SBS modifier by weight. The supplier is Suzhou Sanchuang Road Engineering Co., Ltd., and the quality meets the relevant requirements in the "Technical Specification for Construction of Highway Asphalt Pavement" (JTGF40-2004).

[0043] The high-viscosity modified asphalt is a high-viscosity crack-resistant type, supplied by Beijing Zhongtian Road Industry Technology Co., Ltd., and its quality meets the relevant requirements of the "Technical Specification for Design and Construction of Drainage Asphalt Pavement" (JTGT3350-03-2020).

[0044] The rubber powder modified asphalt is a plant-mixed modified asphalt with a formula of Korean Ssangyong 70# base asphalt plus 10% by weight of 60-mesh rubber powder. The supplier is Suzhou Sanchuang Road Engineering Co., Ltd., and the quality meets the relevant requirements in the "Technical Specification for Construction of Highway Asphalt Pavement" (JTGF40-2004).

[0045] Example 1

[0046] This embodiment describes a method for testing the surface morphology and mechanical properties of asphalt based on atomic force microscopy. The asphalt being tested is a base asphalt, and the method includes the following steps:

[0047] S1. Based on the high-temperature flow characteristics (viscosity) of asphalt, a base asphalt sample is heated and prepared. The resulting asphalt sample includes a chestnut-yellow thin film region, which includes ring-shaped watermarks. This includes the following sub-steps:

[0048] S11. Heat the asphalt sample to make it flowable, and stir it 3 times with a clean glass rod to obtain the stirred asphalt.

[0049] S12. Insert a glass rod into the stirred asphalt obtained in step S11 1-5cm, dip a drop (0.3g) into the glass slide and place it at the top 1 / 5 of the slide to obtain a glass slide with added asphalt.

[0050] S13. The glass slide with the asphalt droplets obtained in step S12 is tilted upwards at 75° and placed in a high-temperature oven at 135° for heat treatment. The asphalt melt flows freely at the interface of the glass slide for 2 minutes. Depending on the chain length and content of polymer chains in different regions inside the melt, turbulence and laminar flow will occur under the action of heat and gravity, thus obtaining the heat-treated asphalt.

[0051] S14. Cool the heat-treated asphalt obtained in step S13 at 20-25℃ for 24 hours to obtain an asphalt sample. The obtained asphalt sample includes a chestnut-yellow film area, which includes ring-shaped watermarks, such as... Figure 1 As shown.

[0052] S2. Using the eyepiece of an atomic force microscope and the ring-shaped water ripples in the chestnut-yellow film area, determine the test path and test area, including the following sub-steps:

[0053] S21. When the probe under the cantilever beam descends to near the designed distance, the edge of the asphalt sample is located using the physical eyepiece of an atomic microscope.

[0054] S22. Move 0.1 cm from the edge of the asphalt sample toward the asphalt sample to find the ring-shaped water ripple;

[0055] S23. Place the virtual image of the triangular cantilever beam in the field of view of the physical eyepiece inside the ring of water ripples, and continue to lower the probe to the designed test distance;

[0056] S24. The recommended test path is from the inside to the outside of the ring water ripple to ensure that the test starting point is located at the highest point of the nanoscale, so as to prevent the probe under the cantilever beam from touching or getting too close to the surface of the asphalt sample in the scanning test direction, which would cause the test morphology or mechanical index map to show point-like pitting that cannot truly reflect the nanoscale information of the asphalt surface, or even cause a small amount of asphalt to adhere to the probe and affect the test of subsequent samples.

[0057] S25. The test area is the area near the ring-shaped water ripple.

[0058] S3. Surface morphology and mechanical properties are tested using an atomic force microscope to obtain test patterns. These test patterns include 2D and 3D images of surface roughness, adhesion force, and Young's modulus. Qualitative and quantitative analysis of the test patterns is performed using Nanoscope Analysis software to obtain surface roughness, adhesion force, and Young's modulus values. This includes the following sub-steps:

[0059] S31. The elastic coefficient of the quasi-cantilever on the atomic force microscope probe was determined through a standard calibration experiment.

[0060] S32. Using PeakForce QNM mode, collect 2D and 3D images of the surface morphology roughness, adhesion force, and Young's modulus values ​​of the test area of ​​the asphalt sample.

[0061] S33. Using Nanoscope Analysis software, perform qualitative and quantitative analysis of the 2D and 3D atlases of surface morphology roughness, adhesion force, and Young's modulus to obtain the surface morphology roughness, adhesion force, and Young's modulus values.

[0062] Example 2

[0063] This embodiment describes a testing method for the surface morphology and mechanical properties of asphalt based on atomic force microscopy. The asphalt tested is SBS-modified asphalt, and includes the following steps:

[0064] S1. Based on the high-temperature flow characteristics (viscosity) of asphalt, heat and prepare styrene-butadiene-styrene triblock copolymer (SBS) modified asphalt samples. The obtained asphalt samples include a chestnut-yellow film region, which includes ring-shaped watermarks. The process includes the following sub-steps:

[0065] S11. Heat the asphalt sample to make it flowable, and stir it 3 times with a clean glass rod to obtain the stirred asphalt.

[0066] S12. Insert a glass rod into the stirred asphalt obtained in step S11, 1-5 cm deep, and place a drop (0.5 g) on ​​the upper 1 / 5 of the glass slide to obtain a glass slide with added asphalt.

[0067] S13. The glass slide with the asphalt droplets obtained in step S12 is tilted upwards at 80° and placed in a high-temperature oven at 170° for heat treatment. The asphalt melt flows freely at the interface of the glass slide for 4 minutes. Depending on the chain length and content of polymer chains in different regions inside the melt, turbulence and laminar flow will occur under the action of heat and gravity, thus obtaining the heat-treated asphalt.

[0068] S14. Cool the heat-treated asphalt obtained in step S13 at 20-25℃ for 24 hours to obtain an asphalt sample. The obtained asphalt sample includes a chestnut yellow film area, which includes ring-shaped watermarks.

[0069] S2. Using the eyepiece of an atomic force microscope and the ring-shaped water ripples in the chestnut-yellow film area, determine the test path and test area, including the following sub-steps:

[0070] S21. When the probe under the cantilever beam descends to near the designed distance, the edge of the asphalt sample is located using the physical eyepiece of an atomic microscope.

[0071] S22. Move 0.1 cm from the edge of the asphalt sample toward the asphalt sample to find the ring-shaped water ripple;

[0072] S23. Place the virtual image of the triangular cantilever beam in the field of view of the physical eyepiece inside the ring of water ripples, and continue to lower the probe to the designed test distance;

[0073] S24. The recommended test path is from the inside to the outside of the ring water ripple to ensure that the test starting point is located at the highest point of the nanoscale, so as to prevent the probe under the cantilever beam from touching or getting too close to the surface of the asphalt sample in the scanning test direction, which would cause the test morphology or mechanical index map to show point-like pitting that cannot truly reflect the nanoscale information of the asphalt surface, or even cause a small amount of asphalt to adhere to the probe and affect the test of subsequent samples.

[0074] S25. The test area is the area near the ring-shaped water ripple.

[0075] S3. Surface morphology and mechanical properties are tested using an atomic force microscope to obtain test patterns. These test patterns include 2D and 3D images of surface roughness, adhesion force, and Young's modulus. Qualitative and quantitative analysis of the test patterns is performed using Nanoscope Analysis software to obtain surface roughness, adhesion force, and Young's modulus values. This includes the following sub-steps:

[0076] S31. The elastic coefficient of the quasi-cantilever on the atomic force microscope probe was determined through a standard calibration experiment.

[0077] S32. Using PeakForce QNM mode, collect 2D and 3D images of the surface morphology roughness, adhesion force, and Young's modulus values ​​of the test area of ​​the asphalt sample.

[0078] S33. Using Nanoscope Analysis software, perform qualitative and quantitative analysis of the 2D and 3D atlases of surface morphology roughness, adhesion force, and Young's modulus to obtain the surface morphology roughness, adhesion force, and Young's modulus values.

[0079] Example 3

[0080] This embodiment describes a testing method for the surface morphology and mechanical properties of asphalt based on atomic force microscopy. The asphalt being tested is high-viscosity modified asphalt, and includes the following steps:

[0081] S1. Based on the high-temperature flow characteristics (viscosity) of asphalt, heat and prepare high-viscosity modified asphalt samples. The resulting asphalt samples include a chestnut-yellow film region, which includes ring-shaped watermarks. This includes the following sub-steps:

[0082] S11. Heat the asphalt sample to make it flowable, and stir it 3 times with a clean glass rod to obtain the stirred asphalt.

[0083] S12. Insert a glass rod into the stirred asphalt obtained in step S11 1-5cm, dip a drop (0.8g) into the glass slide and place it at the top 1 / 5 of the slide to obtain a glass slide with added asphalt.

[0084] S13. The glass slide with the asphalt droplets obtained in step S12 is tilted upwards at 85° and placed in a high-temperature oven at 195° for heat treatment. The asphalt melt flows freely at the interface of the glass slide for at least 8 minutes. Depending on the chain length and content of polymer chains in different regions inside the melt, turbulence and laminar flow will occur under the action of heat and gravity, thus obtaining the heat-treated asphalt.

[0085] S14. Cool the heat-treated asphalt obtained in step S13 at 20-25℃ for 24 hours to obtain an asphalt sample. The obtained asphalt sample includes a chestnut yellow film area, which includes ring-shaped watermarks.

[0086] S2. Using the eyepiece of an atomic force microscope and the ring-shaped water ripples in the chestnut-yellow film area, determine the test path and test area, including the following sub-steps:

[0087] S21. When the probe under the cantilever beam descends to near the designed distance, the edge of the asphalt sample is located using the physical eyepiece of an atomic microscope.

[0088] S22. Move 0.1 cm from the edge of the asphalt sample toward the asphalt sample to find the ring-shaped water ripple;

[0089] S23. Place the virtual image of the triangular cantilever beam in the field of view of the physical eyepiece inside the ring of water ripples, and continue to lower the probe to the designed test distance;

[0090] S24. The recommended test path is from the inside to the outside of the ring water ripple to ensure that the test starting point is located at the highest point of the nanoscale, so as to prevent the probe under the cantilever beam from touching or getting too close to the surface of the asphalt sample in the scanning test direction, which would cause the test morphology or mechanical index map to show point-like pitting that cannot truly reflect the nanoscale information of the asphalt surface, or even cause a small amount of asphalt to adhere to the probe and affect the test of subsequent samples.

[0091] S25. The test area is the area near the ring-shaped water ripple.

[0092] S3. Surface morphology and mechanical properties are tested using an atomic force microscope to obtain test patterns. These test patterns include 2D and 3D images of surface roughness, adhesion force, and Young's modulus. Qualitative and quantitative analysis of the test patterns is performed using Nanoscope Analysis software to obtain surface roughness, adhesion force, and Young's modulus values. This includes the following sub-steps:

[0093] S31. The elastic coefficient of the quasi-cantilever on the atomic force microscope probe was determined through a standard calibration experiment.

[0094] S32. Using PeakForce QNM mode, collect 2D and 3D images of the surface morphology roughness, adhesion force, and Young's modulus values ​​of the test area of ​​the asphalt sample.

[0095] S33. Using Nanoscope Analysis software, perform qualitative and quantitative analysis of the 2D and 3D atlases of surface morphology roughness, adhesion force, and Young's modulus to obtain the surface morphology roughness, adhesion force, and Young's modulus values.

[0096] For Examples 1-3, based on the test methods in the "Brook Dimension ICON Atomic Force Microscope Operation Guide" (for each index, the average of 3 test points is taken), the following was found:

[0097] 1) Compared with other areas, the root mean square error of the surface roughness, adhesion force value and Young's modulus value of the test area around the ring water ripple is significantly reduced.

[0098] 2) As viscosity increases (viscosity: base asphalt < SBS-type modified asphalt < high-viscosity modified asphalt), the rate of decrease in standard deviation (SD) increases, indicating that this testing method is beneficial for eliminating data fluctuations in the nanoscale indicators of modified asphalt and improving data reproducibility. Specific trends are shown in Table 1.

[0099] Table 1 shows the statistical decrease in the mean squared error (SD) of the AFM parameters of the nanostructure around the ring-shaped water ripples in Examples 1-3.

[0100]

[0101] Example 4

[0102] This embodiment describes a method for testing the surface morphology and mechanical properties of asphalt based on atomic force microscopy. The asphalt being tested is a base asphalt, and the method includes the following steps:

[0103] S1. Based on the high-temperature flow characteristics (viscosity) of asphalt, a base asphalt sample is heated and prepared. The resulting asphalt sample includes a chestnut-yellow thin film region, which includes ring-shaped watermarks. This includes the following sub-steps:

[0104] S11. Heat the asphalt sample to make it flowable, and stir it 5 times with a clean glass rod to obtain the stirred asphalt.

[0105] S12. Insert a glass rod into the stirred asphalt obtained in step S11 1-5cm, dip a drop (0.3g) into the glass slide and place it at the top 1 / 5 of the slide to obtain a glass slide with added asphalt.

[0106] S13. The glass slide with the asphalt droplets obtained in step S12 is tilted upwards at 80° and placed in a high-temperature oven at 135° for heat treatment. The asphalt melt flows freely at the interface of the glass slide for 2 minutes. Depending on the chain length and content of polymer chains in different regions inside the melt, turbulence and laminar flow will occur under the action of heat and gravity, thus obtaining the heat-treated asphalt.

[0107] S14. Cool the heat-treated asphalt obtained in step S13 at 20-25℃ for 24 hours to obtain an asphalt sample. The obtained asphalt sample includes a chestnut yellow film area, which includes ring-shaped watermarks.

[0108] S2. Using the eyepiece of an atomic force microscope and the ring-shaped water ripples in the chestnut-yellow film area, determine the test path and test area, including the following sub-steps:

[0109] S21. When the probe under the cantilever beam descends to near the designed distance, the edge of the asphalt sample is located using the physical eyepiece of an atomic microscope.

[0110] S22. Move 0.1 cm from the edge of the asphalt sample toward the asphalt sample to find the ring-shaped water ripple;

[0111] S23. Place the virtual image of the triangular cantilever beam in the field of view of the physical eyepiece inside the ring of water ripples, and continue to lower the probe to the designed test distance;

[0112] S24. The recommended test path is from the inside to the outside of the ring water ripple to ensure that the test starting point is located at the highest point of the nanoscale, so as to prevent the probe under the cantilever beam from touching or getting too close to the surface of the asphalt sample in the scanning test direction, which would cause the test morphology or mechanical index map to show point-like pitting that cannot truly reflect the nanoscale information of the asphalt surface, or even cause a small amount of asphalt to adhere to the probe and affect the test of subsequent samples.

[0113] S25. The test area is the area near the ring-shaped water ripple.

[0114] S3. Surface morphology and mechanical properties are tested using an atomic force microscope to obtain test patterns. These test patterns include 2D and 3D images of surface roughness, adhesion force, and Young's modulus. Qualitative and quantitative analysis of the test patterns is performed using Nanoscope Analysis software to obtain surface roughness, adhesion force, and Young's modulus values. This includes the following sub-steps:

[0115] S31. The elastic coefficient of the quasi-cantilever on the atomic force microscope probe was determined through a standard calibration experiment.

[0116] S32. Using PeakForce QNM mode, collect 2D and 3D images of the surface morphology roughness, adhesion force, and Young's modulus values ​​of the test area of ​​the asphalt sample.

[0117] S33. Using Nanoscope Analysis software, perform qualitative and quantitative analysis of the 2D and 3D atlases of surface morphology roughness, adhesion force, and Young's modulus to obtain the surface morphology roughness, adhesion force, and Young's modulus values.

[0118] Example 5

[0119] This embodiment describes a testing method for the surface morphology and mechanical properties of asphalt based on atomic force microscopy. The asphalt tested is SBS-modified asphalt, and includes the following steps:

[0120] S1. Based on the high-temperature flow characteristics (viscosity) of asphalt, heat and prepare styrene-butadiene-styrene triblock copolymer (SBS) modified asphalt samples. The obtained asphalt samples include a chestnut-yellow film region, which includes ring-shaped watermarks. The process includes the following sub-steps:

[0121] S11. Heat the asphalt sample to make it flowable, and stir it 3 times with a clean glass rod to obtain the stirred asphalt.

[0122] S12. Insert a glass rod into the stirred asphalt obtained in step S11, 1-5 cm deep, and place a drop (0.5 g) on ​​the upper 1 / 5 of the glass slide to obtain a glass slide with added asphalt.

[0123] S13. The glass slide with the asphalt droplets obtained in step S12 is tilted upwards at 80° and placed in a high-temperature oven at 170° for heat treatment. The asphalt melt flows freely at the interface of the glass slide for 4 minutes. Depending on the chain length and content of polymer chains in different regions inside the melt, turbulence and laminar flow will occur under the action of heat and gravity, thus obtaining the heat-treated asphalt.

[0124] S14. Cool the heat-treated asphalt obtained in step S13 at 20-25℃ for 24 hours to obtain an asphalt sample. The obtained asphalt sample includes a chestnut yellow film area, which includes ring-shaped watermarks.

[0125] S2. Using the eyepiece of an atomic force microscope and the ring-shaped water ripples in the chestnut-yellow film area, determine the test path and test area, including the following sub-steps:

[0126] S21. When the probe under the cantilever beam descends to near the designed distance, the edge of the asphalt sample is located using the physical eyepiece of an atomic microscope.

[0127] S22. Move 0.1 cm from the edge of the asphalt sample toward the asphalt sample to find the ring-shaped water ripple;

[0128] S23. Place the virtual image of the triangular cantilever beam in the field of view of the physical eyepiece inside the ring of water ripples, and continue to lower the probe to the designed test distance;

[0129] S24. The recommended test path is from the inside to the outside of the ring water ripple to ensure that the test starting point is located at the highest point of the nanoscale, so as to prevent the probe under the cantilever beam from touching or getting too close to the surface of the asphalt sample in the scanning test direction, which would cause the test morphology or mechanical index map to show point-like pitting that cannot truly reflect the nanoscale information of the asphalt surface, or even cause a small amount of asphalt to adhere to the probe and affect the test of subsequent samples.

[0130] S25. The test area is the area near the ring-shaped water ripple.

[0131] S3. Surface morphology and mechanical properties are tested using an atomic force microscope to obtain test patterns. These test patterns include 2D and 3D images of surface roughness, adhesion force, and Young's modulus. Qualitative and quantitative analysis of the test patterns is performed using Nanoscope Analysis software to obtain surface roughness, adhesion force, and Young's modulus values. This includes the following sub-steps:

[0132] S31. The elastic coefficient of the quasi-cantilever on the atomic force microscope probe was determined through a standard calibration experiment.

[0133] S32. Using PeakForce QNM mode, collect 2D and 3D images of the surface morphology roughness, adhesion force, and Young's modulus values ​​of the test area of ​​the asphalt sample.

[0134] S33. Using Nanoscope Analysis software, perform qualitative and quantitative analysis of the 2D and 3D atlases of surface morphology roughness, adhesion force, and Young's modulus to obtain the surface morphology roughness, adhesion force, and Young's modulus values.

[0135] Example 6

[0136] This embodiment describes a method for testing the surface morphology and mechanical properties of asphalt based on atomic force microscopy. The asphalt tested is rubber powder modified asphalt, and includes the following steps:

[0137] S1. Based on the high-temperature flow characteristics (viscosity) of asphalt, rubber powder modified asphalt is heated and prepared. The resulting asphalt sample includes a chestnut-yellow film area, which includes ring-shaped watermarks. The process includes the following sub-steps:

[0138] S11. Heat the asphalt sample to make it flowable, and stir it 3 times with a clean glass rod to obtain the stirred asphalt.

[0139] S12. Insert a glass rod into the stirred asphalt obtained in step S11 1-5cm, dip a drop (0.4g) into the glass slide and place it at the top 1 / 5 of the slide to obtain a glass slide with added asphalt.

[0140] S13. The glass slide with the asphalt droplets obtained in step S12 is tilted upwards at 80° and placed in a high-temperature oven at 150° for heat treatment. The asphalt melt flows freely at the interface of the glass slide for 3 minutes. Depending on the chain length and content of polymer chains in different regions inside the melt, turbulence and laminar flow will occur under the action of heat and gravity, thus obtaining the heat-treated asphalt.

[0141] S14. Cool the heat-treated asphalt obtained in step S13 at 20-25℃ for 24 hours to obtain an asphalt sample. The obtained asphalt sample includes a chestnut yellow film area, which includes ring-shaped watermarks.

[0142] S2. Using the eyepiece of an atomic force microscope and the ring-shaped water ripples in the chestnut-yellow film area, determine the test path and test area, including the following sub-steps:

[0143] S21. When the probe under the cantilever beam descends to near the designed distance, the edge of the asphalt sample is located using the physical eyepiece of an atomic microscope.

[0144] S22. Move 0.1 cm from the edge of the asphalt sample toward the asphalt sample to find the ring-shaped water ripple;

[0145] S23. Place the virtual image of the triangular cantilever beam in the field of view of the physical eyepiece inside the ring of water ripples, and continue to lower the probe to the designed test distance;

[0146] S24. The recommended test path is from the inside to the outside of the ring water ripple to ensure that the test starting point is located at the highest point of the nanoscale, so as to prevent the probe under the cantilever beam from touching or getting too close to the surface of the asphalt sample in the scanning test direction, which would cause the test morphology or mechanical index map to show point-like pitting that cannot truly reflect the nanoscale information of the asphalt surface, or even cause a small amount of asphalt to adhere to the probe and affect the test of subsequent samples.

[0147] S25. The test area is the area near the ring-shaped water ripple.

[0148] S3. Surface morphology and mechanical properties are tested using an atomic force microscope to obtain test patterns. These test patterns include 2D and 3D images of surface roughness, adhesion force, and Young's modulus. Qualitative and quantitative analysis of the test patterns is performed using Nanoscope Analysis software to obtain surface roughness, adhesion force, and Young's modulus values. This includes the following sub-steps:

[0149] S31. The elastic coefficient of the quasi-cantilever on the atomic force microscope probe was determined through a standard calibration experiment.

[0150] S32. Using PeakForce QNM mode, collect 2D and 3D images of the surface morphology roughness, adhesion force, and Young's modulus values ​​of the test area of ​​the asphalt sample.

[0151] S33. Using Nanoscope Analysis software, perform qualitative and quantitative analysis of the 2D and 3D atlases of surface morphology roughness, adhesion force, and Young's modulus to obtain the surface morphology roughness, adhesion force, and Young's modulus values.

[0152] For Examples 4-6, based on the test methods in the "Brook Dimension ICON Atomic Force Microscope Operation Guide" (for each index, the average of 3 test points is taken), the following was found:

[0153] 1) Compared with other areas, the root mean square error of the surface roughness, adhesion force value and Young's modulus value of the test area around the ring water ripple is significantly reduced.

[0154] 2) As viscosity increases (viscosity: base asphalt < SBS-modified asphalt < rubber powder-modified asphalt), the rate of decrease in standard deviation (SD) increases, indicating that this testing method is beneficial for eliminating data fluctuations in the nanoscale indicators of modified asphalt and improving data reproducibility. Specific trends are shown in Table 2.

[0155] Table 2 shows the statistical decrease in the mean squared error (SD) of the AFM parameters of the nanostructure around the ring-shaped water ripples in Examples 4-6.

[0156]

[0157] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for testing the surface morphology and mechanical properties of asphalt based on atomic force microscopy, characterized in that, Includes the following steps: S1. Based on the macroscopic high-temperature flow characteristics of asphalt, the micron-level coagulation characteristics of polymer chains, and the formation characteristics of stable and uniform nanoscale phase structures, asphalt samples were classified and heated to prepare test specimens. The resulting asphalt specimens showed a chestnut yellow film area, which included ring-shaped water ripples. S2. Using the eyepiece of an atomic force microscope and the ring-shaped water ripples in the chestnut yellow film area, determine the test path and test area; S3. Surface morphology and mechanical properties are tested using an atomic force microscope to obtain test patterns. The test patterns include a set of patterns of surface roughness, a set of patterns of adhesion force values ​​and a set of patterns of Young's modulus values. The test patterns are qualitatively and quantitatively analyzed using NanoscopeAnalysis software to obtain surface roughness, adhesion force values ​​and Young's modulus values. Step S1 includes the following sub-steps: S11. Heat the asphalt sample to make it flowable, stir for 3-5 turns, and obtain the stirred asphalt. S12. Insert a glass rod into the stirred asphalt obtained in step S11, 1-5 cm deep, and place a drop on a glass slide to obtain a glass slide with added asphalt. S13. The glass slide with added asphalt obtained in step S12 is tilted and placed in a high-temperature oven for heat treatment. The asphalt melt flows freely at the interface of the glass slide. Depending on the chain length and content of polymer chains in different regions inside the melt, turbulence and laminar flow will occur under the action of heat and gravity, and heat-treated asphalt is obtained. S14. Cool the heat-treated asphalt obtained in step S13 to obtain an asphalt sample. The obtained asphalt sample includes a chestnut yellow film area, which includes ring-shaped watermarks. The heat treatment conditions described in step S13 are as follows: The heat treatment temperature of the base asphalt is 130-140℃, and the free flow time is 1-3 minutes; The heat treatment temperature for rubber powder modified asphalt is 145-155℃, and the free flow time is 3-4 minutes. The heat treatment temperature for styrene-butadiene-styrene triblock copolymer modified asphalt is 165-175℃, and the free flow time is 4-6 minutes. The heat treatment temperature of the high-viscosity modified asphalt is 185-195℃, and the free flow time is at least 8 minutes, until a chestnut yellow film area appears at the tail of the glass slide; Step S2 includes the following sub-steps: S21. When the probe under the cantilever beam descends to near the designed distance, the edge of the asphalt sample is located using the physical eyepiece of an atomic microscope. S22. Move from the edge of the asphalt sample toward the asphalt sample to find the annular watermark; S23. Place the virtual image of the triangular cantilever beam in the field of view of the physical eyepiece inside the ring of water ripples, and continue to lower the probe to the designed test distance; S24. The test path is from the inside to the outside of the ring water ripple to ensure that the test starting point is located at the highest point of the nanoscale, so as to prevent the probe under the cantilever beam from touching or getting too close to the surface of the asphalt sample in the scanning test forward direction, causing the test morphology or mechanical index map to show point-like pitting that cannot truly reflect the nanoscale information of the asphalt surface, or even the probe to adhere to a trace amount of asphalt that affects the test of subsequent samples. S25. The test area is the area near the ring-shaped water ripples; In step S13, the glass slide with the asphalt dripped on is tilted upwards at 75-85° and placed in a high-temperature oven.

2. According to the method for testing the surface morphology and mechanical properties of asphalt based on atomic force microscopy as described in claim 1, in step S12, a glass rod is inserted 1-5 cm into the stirred asphalt obtained in step S11, and a drop is placed on the upper 1 / 5 of the glass slide. In step S12, a drop is placed on a glass slide. Depending on the type of asphalt, 0.1-1.0g is added to the glass slide. The asphalt is classified as follows: Base asphalt 0.1-0.3g; Rubber powder modified asphalt 0.2-0.4g; 0.4-0.6g of styrene-butadiene-styrene triblock copolymer modified bitumen; 0.5-1.0g of high-viscosity modified asphalt.

3. The method for testing the surface morphology and mechanical properties of asphalt based on atomic force microscopy according to claim 1, characterized in that, The cooling conditions described in step S14 are as follows: cooling temperature 20-25℃, cooling time 24h.

4. The method for testing the surface morphology and mechanical properties of asphalt based on atomic force microscopy according to claim 1, characterized in that, In step S22, the sample is moved 0.05-0.2 cm from the edge of the asphalt sample toward the direction of the asphalt sample.

5. The method for testing the surface morphology and mechanical properties of asphalt based on atomic force microscopy according to claim 1, characterized in that, Step S3 includes the following sub-steps: S31. The elastic coefficient of the quasi-cantilever on the atomic force microscope probe was determined through a standard calibration experiment. S32. Using PeakForce QNM mode, collect atlases of surface morphology roughness, adhesion force values, and Young's modulus values ​​of the test area of ​​the asphalt sample; S33. Using the Nanoscope Analysis software, perform qualitative and quantitative analysis of the graphs and data of the atlas of surface morphology roughness, adhesion force, and Young's modulus to obtain the surface morphology roughness, adhesion force, and Young's modulus values.

6. The method for testing the surface morphology and mechanical properties of asphalt based on atomic force microscopy according to claim 1, characterized in that, The atlas mentioned in step S3 includes 2D and 3D maps.

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