Bio-based modified CNC-Pickering emulsified asphalt and preparation method thereof

Abstract

The invention aims to provide bio-based modified CNC-Pickering emulsified asphalt and a preparation method thereof, and belongs to the technical field of modified emulsified asphalt. Comprising the following components in parts by mass: 45 to 55 parts of matrix asphalt, 45 to 55 parts of deionized water, 1 to 5 parts of cellulose nanocrystal, 0.5 to 1 part of gamma-aminopropyltriethoxysilane, 0.5 to 1.5 parts of sophorolipid, 0.1 to 0.3 part of sodium citrate, 0.1 to 0.3 part of sodium tripolyphosphate, 0.5 to 2 parts of polyvinyl alcohol, 0.1 to 0.3 part of xanthan gum and 0.05 to 0.1 part of butylated hydroxytoluene. The cellulose nanocrystal and Pickering emulsification technology are combined, so that the stability of the emulsified asphalt can be improved, the ageing resistance, high temperature resistance and low temperature resistance of the emulsified asphalt can be improved, and the high-performance requirement of road engineering on the emulsified asphalt can be met.

Description

Technical Field

[0001] The invention belongs to the technical field of modified emulsified asphalt, and specifically relates to a bio-based modified CNC-Pickering emulsified asphalt and a preparation method thereof. Background Art

[0002] Emulsified asphalt is widely used in road construction, maintenance and other engineering fields. Due to its good construction performance and environmental protection, it has become an indispensable and important material in modern road engineering. However, the performance and stability of traditional emulsified asphalt still have certain limitations, especially in terms of temperature changes, storage period and anti-aging, which are easily affected by the environment and process. Therefore, the development of an emulsified asphalt with better performance has become a hot topic in the industry.

[0003] In recent years, with the deepening of environmental protection and sustainable development concepts, the application of bio-based materials has gradually attracted people's attention. Bio-based modification technology can not only improve the performance of asphalt, but also effectively reduce environmental pollution. It is an effective way to improve traditional emulsified asphalt. Cellulose nanocrystals (CNC), as a natural and renewable bio-based material, have been widely used in the development of composite materials, coatings and environmentally friendly materials due to their excellent mechanical properties, degradability and good biocompatibility.

[0004] Pickering emulsification technology is a technology that uses solid particles as emulsifiers. Compared with the traditional surfactant emulsification method, it has a more stable emulsification system and does not produce harmful substances during the emulsification process, which meets the requirements of green environmental protection. Combining cellulose nanocrystals (CNC) with Pickering emulsification technology can effectively improve the stability and performance of emulsified asphalt and enhance its application effect in road engineering.

[0005] At present, although some studies have explored the application of bio-based materials in asphalt, most technologies are still in the laboratory stage and have not yet been widely used in engineering. Summary of the invention

[0006] In view of the shortcomings of the prior art, the present invention proposes a bio-based modified CNC-Pickering emulsified asphalt and a preparation method thereof, which combines cellulose nanocrystals with Pickering emulsification technology, which can not only improve the stability of emulsified asphalt, but also improve its anti-aging, high temperature and low temperature performance, thereby meeting the high performance requirements of emulsified asphalt for road engineering.

[0007] To achieve the above object, the present invention adopts the following technical solution: A bio-based modified CNC-Pickering emulsified asphalt comprises the following components in parts by weight: 45-55 parts of base asphalt, 45-55 parts of deionized water, 1-5 parts of cellulose nanocrystals, 0.5-1 parts of γ-aminopropyltriethoxysilane (γ-APTES), 0.5-1.5 parts of sophorolipids, 0.1-0.3 parts of sodium citrate, 0.1-0.3 parts of sodium tripolyphosphate, 0.5-2 parts of polyvinyl alcohol, 0.1-0.3 parts of xanthan gum, and 0.05-0.1 parts of butylated hydroxytoluene (BHT).

[0008] Furthermore, the cellulose nanocrystal is carboxylated cellulose nanocrystal CNC, with a tensile strength of 6500-7500 MPa, a Young's modulus of 100-150 GPa, a crystallinity>90%, a length of 150-200 nm, a diameter of 3-20 nm, and a surface carboxyl content of 0.3-1.0 mmol / g.

[0009] Furthermore, the γ-aminopropyltriethoxysilane (γ-APTES) is a colorless to yellow liquid with a content of ≥98.0%.

[0010] Furthermore, the sophorolipid is a light yellow to brown liquid with a pH of 6-8, a content of ≥50±5%, and a viscosity of 500-2000.

[0011] Furthermore, the sodium citrate is anhydrous sodium citrate, white powder, and has a content of ≥98.0%.

[0012] Furthermore, the sodium tripolyphosphate is a white powder or granules, with iron (Fe) ≤ 0.05%, content ≥ 92.0%, and water-insoluble matter ≤ 0.05%.

[0013] Furthermore, the polyvinyl alcohol is in the form of white or milky white powder or granules, with a content of ≥99.0%, volatile matter ≤9.0%, and sodium hydroxide ≤0.2%.

[0014] Furthermore, the xanthan gum is a milky white to light yellowish brown solid, with a drying loss of ≤15% and an ash content of 5.5-16.0%.

[0015] Furthermore, the butylated hydroxytoluene (BHT) is a white crystal with a moisture content of ≤0.1%, a residue on ignition of ≤0.01%, and a sulfate (measured as SO4) of ≤0.002%.

[0016] A method for preparing a bio-based modified CNC-Pickering emulsified asphalt comprises the following steps: S1. Pre-treatment Base asphalt: Heat the base asphalt to 140°C (the specific temperature depends on the softening point of the asphalt) until the asphalt becomes fluid, avoiding excessive oxidation of the asphalt due to excessive temperature; Deionized water: Heat the deionized water to 60°C to accelerate the subsequent dissolution process; Cellulose nanocrystals (CNC): Mix cellulose nanocrystals with 40 parts of deionized water and disperse them using an ultrasonic processor to ensure that the cellulose nanocrystals are fully dispersed into single nanocrystals. The ultrasonic treatment time is 30 minutes to ensure that the cellulose nanocrystals are evenly dispersed; S2. Preparation of aqueous phase CNC, sophorolipids, γ-aminopropyltriethoxysilane (γ-APTES): Add γ-aminopropyltriethoxysilane (γ-APTES) to the dispersed CNC solution and keep stirring. While stirring, control the temperature at 60°C to promote the reaction between γ-aminopropyltriethoxysilane and CNC. The reaction time is 4 hours. Then, sophorolipids are added and stirred for 60 minutes to ensure that they are completely dispersed and fully react with the CNC surface to obtain an aqueous phase solution. Sodium citrate, sodium tripolyphosphate, polyvinyl alcohol and xanthan gum: sodium citrate, sodium tripolyphosphate, polyvinyl alcohol and xanthan gum are added to the remaining deionized water to dissolve and disperse, and stirred with a magnetic stirrer or a stirrer at a stirring speed of 500 rpm for 30 minutes until all solid components are completely dissolved to obtain a second aqueous phase solution; Slowly add the aqueous phase 2 solution to the prepared aqueous phase 1 solution, and start the high shear homogenizer while stirring to ensure uniform mixing of aqueous phase 2 and aqueous phase 1. The shear rate is set to 5000 rpm and the mixing time is 30 minutes, until the cellulose nanocrystals in the aqueous phase are completely dispersed to obtain a mixed soap solution; S3, oil phase treatment Add BHT to the preheated base asphalt in S1 and stir thoroughly for 30 minutes to prevent oxidation and aging of the base asphalt; S4. Emulsification process The mixed soap solution obtained in S2 and the oil phase obtained in S3 are passed through a colloid mill and pumped into the colloid mill for primary grinding. The grinding gap is 1.2 mm and the rotation speed during grinding is 12000 rpm to obtain an initial emulsified asphalt liquid. During the emulsification process, the electric field generator is started to apply an electric field force to the emulsion, using a direct current electric field (DC), with the following specific settings: electric field strength: 5 kV / cm, adjusted according to emulsification requirements; application time: during the emulsification process, the electric field force lasts for 30 minutes, which is adjusted according to the stability and particle size requirements of the emulsion; in order to further refine the emulsion particle size and improve stability, the emulsion can be treated with an ultrasonic processor: the ultrasonic treatment time is 5 minutes, which can be adjusted according to the viscosity and particle size of the emulsion; Post-processing After the emulsified asphalt is completed, cool it to room temperature and store it in a sealed container to avoid moisture or long-term exposure to air that may cause demulsification.

[0017] The beneficial effects of the present invention are as follows: Bio-based modified CNC-Pickering emulsified asphalt is an emulsified asphalt that is stabilized and functionally enhanced through the synergistic effect of nanocellulose crystals (CNCs) and other bio-based materials. Its main ingredients include base asphalt, deionized water, cellulose nanocrystals, γ-aminopropyl triethoxysilane, sophorolipids, sodium citrate, sodium tripolyphosphate, polyvinyl alcohol, xanthan gum, and butylated hydroxytoluene (BHT).

[0018] As the basis of emulsified asphalt, base asphalt provides adhesion and strength to ensure its stability on the road surface. Deionized water is used as a solvent in the emulsification process to improve the stability of emulsified asphalt and reduce the impact of impurities. Cellulose nanocrystals (CNC), as the core material in Pickering emulsification technology, mainly play an interfacial stabilization role. Its nanoscale size and surface characteristics enable it to effectively form a stable emulsified structure at the water-asphalt interface, prevent the occurrence of stratification, significantly improve the stability of emulsified asphalt, and enhance its anti-aging, high temperature and low temperature performance.

[0019] γ-aminopropyltriethoxysilane, as a coupling agent, promotes the interaction between cellulose nanocrystals and matrix asphalt, enhances the interfacial adhesion, and improves the water resistance and antioxidant capacity of emulsified asphalt. Sophorolipids, as a natural surfactant, reduce the interfacial tension between water and asphalt, improve the emulsification effect, help cellulose nanocrystals to disperse evenly, and improve the anti-aging properties of emulsified asphalt. Sodium citrate adjusts the pH value of the emulsification system, optimizes the emulsification process, enhances the affinity between the water phase and the oil phase, and thus improves the stability of the emulsified asphalt.

[0020] Sodium tripolyphosphate plays a major role in stabilizing the emulsified system in emulsified asphalt. It improves the dispersion of asphalt particles by increasing the concentration of ions in the water phase, thereby effectively preventing the agglomeration or sedimentation of asphalt particles. It can also improve the rheological properties of emulsified asphalt, increase the operability of emulsified asphalt under different working conditions, and extend its storage period to ensure the long-term stability of emulsified asphalt.

[0021] Polyvinyl alcohol improves the construction performance of emulsified asphalt in low temperature environment by enhancing the adhesion and mechanical strength of emulsified asphalt, and enhances the stability and freeze-thaw resistance of emulsified asphalt. Xanthan gum, as a thickener and stabilizer, improves the viscosity and rheological properties of emulsified asphalt, and enhances its anti-settling, water resistance and anti-aging properties. Butylated hydroxytoluene (BHT) as an antioxidant prevents the oxidation and degradation of emulsified asphalt, and significantly improves its high temperature resistance and anti-aging ability.

[0022] Through the synergistic effect of these components, bio-based modified CNC-Pickering emulsified asphalt shows excellent performance in stability, adhesion, mechanical properties, etc., which can meet the needs of modern road engineering for high-performance emulsified asphalt, while also meeting the requirements of environmental protection and sustainable development. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Unless otherwise specified, all raw materials used in the examples are commercially available conventional raw materials, and the technical means used are conventional means well known to those skilled in the art.

[0025] The bio-based modified CNC-Pickering emulsified asphalt of the present invention includes base asphalt, deionized water, cellulose nanocrystals, γ-aminopropyl triethoxysilane (γ-APTES), sophorolipids, sodium citrate, sodium tripolyphosphate, polyvinyl alcohol, xanthan gum, and butylated hydroxytoluene (BHT); the cellulose nanocrystals are carboxylated cellulose nanocrystals CNC, with a tensile strength of 6500-7500MPa, a Young's modulus of 100-150GPa, a crystallinity of>90%, a length of 150-200nm, a diameter of 3-20nm, and a surface carboxyl content of 0.3-1.0 mmol / g. Sophorolipids are light yellow to brown liquids with a pH of 6-8, a content of ≥50±5%, and a viscosity of 500-2000. γ-aminopropyl triethoxysilane (γ-APTES) is a colorless to yellow liquid with a content of ≥98.0%. Xanthan gum is a milky white to light yellowish brown solid, with a drying loss of ≤15% and an ash content of 5.5~16.0%. Sodium citrate is anhydrous sodium citrate, white powder, and the content is ≥98.0%. Sodium tripolyphosphate is a white powder or granules, iron (Fe) ≤0.05%, content ≥92.0%, and water-insoluble matter ≤0.05%. Polyvinyl alcohol is a white or milky white powder or granules, with a content of ≥99.0%, volatile matter ≤9.0%, and sodium hydroxide ≤0.2%. Butylated hydroxytoluene (BHT) is a white crystal, with a moisture content of ≤0.1%, a residue on ignition ≤0.01%, and a sulfate (as SO4) ≤0.002%.

[0026] The dosage and parameters of each component in Examples 1-9 of the present invention are shown in Table 1.

[0027] Table 1 Dosage and parameters of each component The bio-based modified CNC-Pickering emulsified asphalt of the present invention is produced in the following process: S1. Pre-treatment Matrix asphalt: Heat the matrix asphalt to 140°C until the asphalt becomes fluid, avoiding excessive oxidation of the asphalt due to excessive temperature.

[0028] Deionized water: Heat the deionized water to 60°C to accelerate the subsequent dissolution process.

[0029] Cellulose nanocrystals (CNC): Mix cellulose nanocrystals with deionized water (40 parts) and disperse them using an ultrasonic processor to ensure that the cellulose nanocrystals are fully dispersed into individual nanocrystals. Ultrasonic treatment time is 30 minutes to ensure that the cellulose nanocrystals are evenly dispersed.

[0030] S2. Preparation of aqueous phase CNC, sophorolipids, γ-aminopropyltriethoxysilane (γ-APTES): Add γ-aminopropyltriethoxysilane (γ-APTES) to the dispersed CNC solution and keep stirring. While stirring, control the temperature at 60°C to promote the reaction of the silane coupling agent with CNC, and the reaction time is 4 hours. Then add sophorolipids and stir for 60 minutes to ensure that it is completely dispersed and fully reacts with the CNC surface to obtain an aqueous phase solution; Sodium citrate, sodium tripolyphosphate, polyvinyl alcohol and xanthan gum: Sodium citrate, sodium tripolyphosphate, polyvinyl alcohol and xanthan gum are added to the remaining aqueous phase to dissolve and disperse. A magnetic stirrer or a stirrer is used to stir at a speed of 500 rpm for about 30 minutes until all solid components are completely dissolved to obtain an aqueous phase II solution.

[0031] Slowly add the aqueous phase 2 solution to the prepared aqueous phase 1 solution. While stirring, start the high shear homogenizer to ensure uniform mixing of aqueous phase 2 and aqueous phase 1. The shear rate is set to 5000 rpm and the mixing time is 30 minutes until the cellulose nanocrystals in the aqueous phase are completely dispersed to obtain a mixed soap solution.

[0032] S3, oil phase treatment BHT can be added to the preheated asphalt and stirred thoroughly for 30 minutes to prevent oxidation and aging of the asphalt.

[0033] S4. Emulsification process The soap solution and the heated base asphalt are passed through a colloid mill and pumped into the colloid mill for primary grinding. The grinding gap is 1.2 mm and the speed during grinding is 12000 rpm to obtain the initial emulsified asphalt liquid. During the emulsification process, the electric field generator is started to apply an electric field force to the emulsion, using a direct current electric field (DC), with the following specific settings: Electric field strength: 5 kV / cm, adjusted according to emulsification requirements. Application time: During the emulsification process, the electric field force lasts for 30 minutes, which is adjusted according to the stability and particle size requirements of the emulsion. In order to further refine the emulsion particle size and improve stability, the emulsion can be treated with an ultrasonic processor: The ultrasonic treatment time is 5 minutes, which can be adjusted according to the viscosity and particle size of the emulsion.

[0034] S5. Post-processing After the emulsified asphalt is completed, cool it to room temperature and store it in a sealed container to avoid moisture or long-term exposure to air that may cause demulsification.

[0035] Comparative Example 1 This comparative example provides a CNC-Pickering emulsified asphalt, including base asphalt, water, cellulose nanocrystals (CNCs), and polyvinyl alcohol, wherein the components are as follows in mass fraction: 45 parts of base asphalt, 50 parts of deionized water, 2.5 parts of cellulose nanocrystals (CNCs), and 0.5 parts of polyvinyl alcohol.

[0036] Comparative Example 2 This comparative example provides a CNC-Pickering emulsified asphalt, including base asphalt, water, sophorolipids, and polyvinyl alcohol, wherein the components are as follows in mass fraction: 45 parts of base asphalt, 50 parts of deionized water, 1.5 parts of sophorolipids, and 0.5 parts of polyvinyl alcohol.

[0037] The present invention further tests the performance of the emulsified asphalt in the embodiment and the comparative example, and the test indicators are storage stability, adhesion performance, compatibility and water damage resistance. The test method is as follows: Storage stability: The storage stability of emulsified asphalt is tested using the emulsified asphalt storage stability test (T0655-1993) in the "Test Procedure for Asphalt and Asphalt Mixtures for Highway Engineering" (JTGE20-2011).

[0038] Adhesion performance: The adhesion performance of emulsified asphalt was tested using the adhesion test of emulsified asphalt and coarse aggregate (T0654-2011) in the "Test Procedure for Asphalt and Asphalt Mixtures in Highway Engineering" (JTGE20-2011).

[0039] Water damage resistance: The water damage resistance of emulsified asphalt slurry is tested using the slurry mixture wet wheel abrasion test (T0752-2011) in the "Test Procedures for Asphalt and Asphalt Mixtures for Highway Engineering" (JTGE20-2011).

[0040] Interlayer pull-out performance: The interlayer pull-out strength of emulsified asphalt is tested using the "Highway Engineering Quality Inspection and Assessment Standard Volume 1 Civil Engineering" (JTG F80 / 1-2017) Positive Tensile Bond Strength Assessment between Waterproof Layer and Concrete (Appendix N).

[0041] The test results are shown in Table 2.

[0042] Table 2 Test results According to the data in Table 2, the bio-based modified CNC-Pickering emulsified asphalt prepared in the embodiments of the present invention exhibits excellent performance in storage stability, adhesion performance, water damage resistance and pull-out resistance. By comparing the results of Examples 1-9 with Comparative Examples 1-2, it can be seen that the storage stability of the obtained bio-based modified CNC-Pickering emulsified asphalt is generally less than 1.0% in 1 day, and the storage stability in 5 days is less than 2.0%. Compared with ordinary CNC-Pickering emulsified asphalt, its storage stability has been significantly improved. In the adhesion test, all bio-based modified CNC-Pickering emulsified asphalts passed the qualified test, and the wet wheel abrasion values ​​were less than 320 g / m in the 1-hour test. 2 Compared with ordinary CNC-Pickering emulsified asphalt, its adhesion is significantly enhanced. In addition, the pull-out strength is generally greater than 0.35 MPa, and its mechanical properties are also significantly improved compared with ordinary CNC-Pickering emulsified asphalt.

[0043] According to the comparison results of Example 1 and Comparative Example 1, the CNC-Pickering emulsified asphalt prepared using CNC alone has poor stability, weak adhesion and mechanical properties. In contrast, the bio-based modified CNC-Pickering emulsified asphalt involved in the present invention exhibits excellent stability, mechanical properties and adhesion. An appropriate increase in CNC can improve storage stability, adhesion and mechanical properties to a certain extent. According to the comparison results of Example 1 and Comparative Example 2, the emulsified asphalt prepared using sophorolipids alone has unstable storage stability, weak adhesion and mechanical properties. In contrast, the CNC-Pickering emulsified asphalt of the present invention overcomes these problems, and an appropriate increase in sophorolipids can improve storage stability to a certain extent. From the comparison results of Example 1 and Example 4, it can be seen that an appropriate increase in CNC and sophorolipids helps to improve storage stability, adhesion and mechanical properties. According to the comparison of Example 1 and Example 5, a moderate increase in γ-APTES can further enhance the stability of the emulsified asphalt. By comparing Example 1 and Example 6, it can be found that an appropriate increase in CNC, sophorolipids and γ-APTES helps to improve storage stability, adhesion and mechanical properties. According to the comparison results of Example 1, Example 7 and Example 9, the addition of sodium citrate, sodium tripolyphosphate and BHT in appropriate amounts has almost no significant effect on the stability and mechanical properties of CNC-Pickering emulsified asphalt. Finally, by comparing Example 1 and Example 8, it can be seen that the addition of xanthan gum in appropriate amounts can significantly improve the stability of emulsified asphalt.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A bio-based modified CNC-Pickering emulsified asphalt, characterized in that: The invention comprises the following components in parts by weight: 45-55 parts of matrix asphalt, 45-55 parts of deionized water, 1-5 parts of cellulose nanocrystals, 0.5-1 parts of γ-aminopropyltriethoxysilane, 0.5-1.5 parts of sophorolipids, 0.1-0.3 parts of sodium citrate, 0.1-0.3 parts of sodium tripolyphosphate, 0.5-2 parts of polyvinyl alcohol, 0.1-0.3 parts of xanthan gum and 0.05-0.1 parts of butylated hydroxytoluene.

2. A bio-based modified CNC-Pickering emulsified asphalt according to claim 1, characterized in that: The cellulose nanocrystal is carboxylated cellulose nanocrystal CNC, with a tensile strength of 6500-7500 MPa, a Young's modulus of 100-150 GPa, a crystallinity of more than 90%, a length of 150-200 nm, a diameter of 3-20 nm, and a surface carboxyl content of 0.3-1.0 mmol / g.

3. The bio-based modified CNC-Pickering emulsified asphalt according to claim 1, characterized in that: The γ-aminopropyltriethoxysilane is a colorless to yellow liquid with a content of ≥98.0%.

4. The bio-based modified CNC-Pickering emulsified asphalt according to claim 1, characterized in that: The sophorolipid is a light yellow to brown liquid with a pH of 6-8, a content of ≥50±5%, and a viscosity of 500-2000.

5. The bio-based modified CNC-Pickering emulsified asphalt according to claim 1, characterized in that: The sodium citrate is anhydrous sodium citrate, white powder, and has a content of ≥98.0%.

6. The bio-based modified CNC-Pickering emulsified asphalt according to claim 1, characterized in that: The sodium tripolyphosphate is white powder or granules, with iron (Fe) ≤ 0.05%, content ≥ 92.0%, and water-insoluble matter ≤ 0.05%.

7. The bio-based modified CNC-Pickering emulsified asphalt according to claim 1, characterized in that: The polyvinyl alcohol is white or milky white powder or granules, with a content of ≥99.0%, volatile matter ≤9.0%, and sodium hydroxide ≤0.2%.

8. The bio-based modified CNC-Pickering emulsified asphalt according to claim 1, characterized in that: The xanthan gum is a milky white to light yellowish brown solid, with a drying loss of ≤15% and an ash content of 5.5-16.0%.

9. The bio-based modified CNC-Pickering emulsified asphalt according to claim 1, characterized in that: The butylated hydroxytoluene is a white crystal, with a moisture content of ≤0.1%, a residue on ignition of ≤0.01%, and a sulfate content of ≤0.002%.

10. A method for preparing the bio-based modified CNC-Pickering emulsified asphalt according to claim 1, characterized in that: The steps include: S1. Pre-treatment Base asphalt: Heat the base asphalt to 140°C until the asphalt becomes fluid, avoiding excessive oxidation of the asphalt due to excessive temperature; Deionized water: Heat the deionized water to 60°C to accelerate the subsequent dissolution process; Cellulose nanocrystals: Mix cellulose nanocrystals with 40 parts of deionized water and disperse them using an ultrasonic processor to ensure that the cellulose nanocrystals are fully dispersed into single nanocrystals. The ultrasonic treatment time is 30 minutes to ensure that the cellulose nanocrystals are evenly dispersed. S2. Preparation of aqueous phase CNC, sophorolipids, γ-aminopropyltriethoxysilane: add γ-aminopropyltriethoxysilane to the dispersed CNC solution and keep stirring. While stirring, control the temperature at 60°C to promote the reaction between γ-aminopropyltriethoxysilane and CNC. The reaction time is 4 hours. Then, sophorolipids are added and stirred for 60 minutes to ensure that they are completely dispersed and fully react with the CNC surface to obtain an aqueous phase solution. Sodium citrate, sodium tripolyphosphate, polyvinyl alcohol and xanthan gum: sodium citrate, sodium tripolyphosphate, polyvinyl alcohol and xanthan gum are added to the remaining deionized water to dissolve and disperse, and stirred with a magnetic stirrer or a stirrer at a stirring speed of 500 rpm for 30 minutes until all solid components are completely dissolved to obtain a second aqueous phase solution; The aqueous phase II solution was slowly added to the prepared aqueous phase I solution. While stirring, a high shear homogenizer was started to ensure uniform mixing of the aqueous phase II and the aqueous phase I. The shear rate was set to 5000 rpm and the mixing time was 30 minutes until the cellulose nanocrystals in the aqueous phase were completely dispersed to obtain a mixed soap solution. S3, oil phase treatment Add BHT to the preheated base asphalt in S1 and stir thoroughly for 30 minutes to prevent oxidation and aging of the base asphalt; S4. Emulsification process The mixed soap solution obtained in S2 and the oil phase obtained in S3 are passed through a colloid mill and pumped into the colloid mill for primary grinding. The grinding gap is 1.2 mm and the rotation speed during grinding is 12000 rpm to obtain an initial emulsified asphalt solution. During the emulsification process, the electric field generator is started to apply electric field force in the emulsion, using a direct current electric field with the following specific settings: electric field strength: 5 kV / cm, adjusted according to emulsification requirements; application time: during the emulsification process, the electric field force lasts for 30 minutes, which is adjusted according to the stability and particle size requirements of the emulsion; in order to further refine the emulsion particle size and improve the stability, the emulsion can be treated with an ultrasonic processor: the ultrasonic treatment time is 5 minutes, which can be adjusted according to the viscosity and particle size of the emulsion; Post-processing After the emulsified asphalt is completed, cool it to room temperature and store it in a sealed container to avoid moisture or long-term exposure to air that may cause demulsification.

Images