A bio-based modified CNC-pickering emulsified asphalt and a preparation method thereof

Abstract

The present application aims at providing a bio-based modified CNC-Pickering emulsified asphalt and a preparation method thereof, belonging to the technical field of modified emulsified asphalt, comprising the following components in mass fraction: base asphalt 45-55 parts, deionized water 45-55 parts, cellulose nanocrystal 1-5 parts, gamma-aminopropyl triethoxysilane 0.5-1 part, sophorolipid 0.5-1.5 parts, sodium citrate 0.1-0.3 parts, sodium tripolyphosphate 0.1-0.3 parts, polyvinyl alcohol 0.5-2 parts, xanthan gum 0.1-0.3 parts, and dibutyl hydroxytoluene 0.05-0.1 part. The present application combines cellulose nanocrystal and 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, meeting the high-performance requirements of road engineering on emulsified asphalt.

Description

Technical Field

[0001] This invention belongs to the field of modified emulsified asphalt technology, specifically relating to a bio-based modified CNC-Pickering emulsified asphalt and its preparation method. Background Technology

[0002] Emulsified asphalt is widely used in road construction, maintenance, and other engineering fields. Due to its excellent workability and environmental friendliness, it has become an indispensable 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 aging resistance, which are easily affected by environmental and process factors. Therefore, developing an emulsified asphalt with superior performance has become a hot research 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, making it 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, biodegradability, and good biocompatibility.

[0004] Pickering emulsification technology is a technique that uses solid particles as emulsifiers. Compared to traditional surfactant emulsification methods, it offers a more stable emulsion system and does not produce harmful substances during the emulsification process, meeting green and environmentally friendly requirements. Combining cellulose nanocrystals (CNC) with Pickering emulsification technology can effectively improve the stability and performance of emulsified asphalt, enhancing its application in road engineering.

[0005] Currently, 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 achieved widespread engineering applications. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention proposes a bio-based modified CNC-Pickering emulsified asphalt and its preparation method. By combining cellulose nanocrystals and Pickering emulsification technology, it can not only improve the stability of emulsified asphalt, but also enhance its anti-aging, high-temperature and low-temperature performance, thus meeting the high-performance requirements of road engineering for emulsified asphalt.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A bio-based modified CNC-Pickering emulsified asphalt comprises the following components in parts by weight: 45-55 parts base asphalt, 45-55 parts deionized water, 1-5 parts cellulose nanocrystals, 0.5-1 parts γ-aminopropyltriethoxysilane (γ-APTES), 0.5-1.5 parts sophorolipid, 0.1-0.3 parts sodium citrate, 0.1-0.3 parts sodium tripolyphosphate, 0.5-2 parts polyvinyl alcohol, 0.1-0.3 parts xanthan gum, and 0.05-0.1 parts butylated hydroxytoluene (BHT).

[0009] Furthermore, the cellulose nanocrystals are carboxylated cellulose nanocrystals (CNC) with a tensile strength of 6500-7500 MPa, a Young's modulus of 100-150 GPa, a crystallinity of >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.

[0010] Furthermore, the γ-aminopropyltriethoxysilane (γ-APTES) is a colorless to yellow liquid with a content ≥98.0%.

[0011] 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.

[0012] Furthermore, the sodium citrate is anhydrous sodium citrate, a white powder, with a content ≥98.0%.

[0013] Furthermore, the sodium tripolyphosphate is a white powder or granules, with iron (Fe) ≤0.05% and a content ≥92.0%, and water-insoluble matter ≤0.05%.

[0014] Furthermore, the polyvinyl alcohol is a white or off-white powder or granules with a content ≥99.0%, volatile matter ≤9.0%, and sodium hydroxide ≤0.2%.

[0015] 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%.

[0016] Furthermore, the butylated hydroxytoluene (BHT) is a white crystalline solid with a moisture content of ≤0.1%, a residue on ignition of ≤0.01%, and a sulfate content (as SO4) of ≤0.002%.

[0017] A method for preparing bio-based modified CNC-Pickering emulsified bitumen includes the following steps:

[0018] S1, Preprocessing

[0019] Base asphalt: Heat the base asphalt to 140℃ (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;

[0020] Deionized water: Heat deionized water to 60°C to accelerate the subsequent dissolution process;

[0021] 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 individual nanocrystals. The ultrasonic treatment time is 30 minutes to ensure that the cellulose nanocrystals are uniformly dispersed.

[0022] S2, Aqueous Phase Preparation

[0023] CNC, sophorolipid, 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 add sophorolipid and stir for 60 minutes to ensure complete dispersion and full reaction with the CNC surface to obtain an aqueous solution.

[0024] Sodium citrate, sodium tripolyphosphate, polyvinyl alcohol and xanthan gum: Add sodium citrate, sodium tripolyphosphate, polyvinyl alcohol and xanthan gum to the remaining deionized water, dissolve and disperse them, and stir using a magnetic stirrer or stirrer at a speed of 500 rpm for 30 minutes until all solid components are completely dissolved to obtain an aqueous phase II solution;

[0025] 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 aqueous phase II and 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, yielding a mixed soap solution.

[0026] S3, Oil Phase Treatment

[0027] Add BHT to the preheated base asphalt in S1 and stir thoroughly for 30 minutes to prevent oxidation and aging of the base asphalt.

[0028] S4, Emulsification process

[0029] The mixed soap solution obtained in S2 and the oil phase obtained in S3 were passed through a colloid mill and pumped into the colloid mill for primary grinding. The grinding gap was 1.2 mm and the grinding speed was 12000 rpm to obtain the initial emulsified asphalt solution.

[0030] During emulsification, the electric field generator is activated to apply an electric field force to the emulsion using a direct current (DC) electric field. Specific settings are as follows: Electric field strength: 5 kV / cm, adjustable according to emulsification requirements; Application time: The electric field force is applied continuously for 30 minutes during emulsification, adjusted according to the stability and particle size requirements of the emulsion. To further refine the emulsion particle size and improve stability, an ultrasonic processor can be used to treat the emulsion: Ultrasonic treatment time is 5 minutes, adjustable according to the viscosity and particle size of the emulsion.

[0031] Post-processing

[0032] After emulsification of asphalt is completed, it should be cooled to room temperature and stored in a sealed container to avoid moisture or prolonged exposure to air, which could lead to demulsification.

[0033] The beneficial effects of this invention are as follows:

[0034] Bio-based modified CNC-Pickering emulsified bitumen is an emulsified bitumen that achieves stabilization and functional enhancement through the synergistic effect of nanocellulose crystals (CNCs) and other bio-based materials. Its main components include base bitumen, deionized water, cellulose nanocrystals, γ-aminopropyltriethoxysilane, sophorolipid, sodium citrate, sodium tripolyphosphate, polyvinyl alcohol, xanthan gum, and butylated hydroxytoluene (BHT).

[0035] Base asphalt, serving as the foundation of emulsified asphalt, provides adhesion and strength, ensuring its stability on the road surface. Deionized water is used as a solvent during the emulsification process, enhancing the stability of the emulsified asphalt and reducing the impact of impurities. Cellulose nanocrystals (CNC), as the core material in Pickering emulsification technology, primarily play a role in interface stabilization. Their nanoscale size and surface properties enable them to effectively form a stable emulsion structure at the water-asphalt interface, preventing delamination, significantly improving the stability of the emulsified asphalt, and enhancing its anti-aging, high-temperature, and low-temperature properties.

[0036] γ-aminopropyltriethoxysilane, acting as a coupling agent, promoted the interaction between cellulose nanocrystals and the matrix asphalt, enhanced interfacial adhesion, and improved the water resistance and antioxidant capacity of the emulsified asphalt. Sophorolipids, as a natural surfactant, reduced the interfacial tension between water and asphalt, improved the emulsification effect, helped to uniformly disperse cellulose nanocrystals, and enhanced the anti-aging properties of the emulsified asphalt. Sodium citrate adjusted the pH of the emulsification system, optimized the emulsification process, enhanced the affinity between the aqueous and oil phases, and thus improved the stability of the emulsified asphalt.

[0037] Sodium tripolyphosphate primarily functions to stabilize the emulsion system in emulsified asphalt. It improves the dispersibility of asphalt particles by increasing the concentration of ions in the aqueous phase, thereby effectively preventing particle aggregation or sedimentation. It also enhances the rheological properties of emulsified asphalt, increases its workability under various operating conditions, and extends its shelf life, ensuring its long-term stability.

[0038] Polyvinyl alcohol enhances the adhesion and mechanical strength of emulsified asphalt, improving its workability at low temperatures and enhancing its stability and freeze-thaw resistance. Xanthan gum, as a thickener and stabilizer, improves the viscosity and rheological properties of emulsified asphalt, enhancing its anti-settling, water resistance, and anti-aging properties. Butylated hydroxytoluene (BHT), as an antioxidant, prevents the oxidative degradation of emulsified asphalt, significantly improving its high-temperature resistance and anti-aging ability.

[0039] Through the synergistic effect of these components, bio-based modified CNC-Pickering emulsified asphalt exhibits excellent performance in terms of stability, adhesion, and mechanical properties, meeting the needs of modern road engineering for high-performance emulsified asphalt while also complying with environmental protection and sustainable development requirements. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0041] Unless otherwise specified, all raw materials used in the embodiments are commercially available conventional raw materials, and the technical means used are conventional means well known to those skilled in the art.

[0042] The bio-based modified CNC-Pickering emulsified asphalt of this invention comprises base asphalt, deionized water, cellulose nanocrystals, γ-aminopropyltriethoxysilane (γ-APTES), sophorolipid, 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 6500-7500 MPa, Young's modulus of 100-150 GPa, crystallinity >90%, length of 150-200 nm, diameter of 3-20 nm, and surface carboxyl content of 0.3-1.0 mmol / g. Sophorolipid is a light yellow to brown liquid with a pH of 6-8, a content ≥50±5%, and a viscosity of 500-2000. γ-aminopropyltriethoxysilane (γ-APTES) is a colorless to yellow liquid with a content ≥98.0%. Xanthan gum is a milky white to pale yellowish-brown solid with a drying loss ≤15% and ash content of 5.5~16.0%. Sodium citrate is anhydrous sodium citrate, a white powder with a content ≥98.0%. Sodium tripolyphosphate is a white powder or granules with iron (Fe) ≤0.05% and a content ≥92.0%, and water-insoluble matter ≤0.05%. Polyvinyl alcohol is a white or milky white powder or granules with a content ≥99.0%, volatile matter ≤9.0%, and sodium hydroxide ≤0.2%. Butylated hydroxytoluene (BHT) is a white crystal with moisture ≤0.1%, residue on ignition ≤0.01%, and sulfate (as SO4) ≤0.002%.

[0043] The dosage and parameters of each component in Examples 1-9 of this invention are shown in Table 1.

[0044] Table 1 Dosage and parameters of each component

[0045]

[0046] The bio-based modified CNC-Pickering emulsified asphalt of the present invention is prepared as follows:

[0047] S1, Preprocessing

[0048] Base asphalt: Heat the base asphalt to 140°C until it becomes fluid, avoiding excessive oxidation of the asphalt due to excessive temperature.

[0049] Deionized water: Deionized water is heated to 60°C to accelerate the subsequent dissolution process.

[0050] Cellulose nanocrystals (CNC): 40 parts of cellulose nanocrystals were mixed with deionized water and dispersed using an ultrasonic processor to ensure that the cellulose nanocrystals were fully dispersed into individual nanocrystals. The ultrasonic treatment time was 30 minutes to ensure uniform dispersion of the cellulose nanocrystals.

[0051] S2, Aqueous Phase Preparation

[0052] CNC, sophorolipid, γ-aminopropyltriethoxysilane (γ-APTES): γ-aminopropyltriethoxysilane (γ-APTES) was added to the dispersed CNC solution while stirring. The temperature was maintained at 60°C during stirring to promote the reaction between the silane coupling agent and CNC, and the reaction time was 4 hours. Then, sophorolipid was added, and the mixture was stirred for 60 minutes to ensure complete dispersion and full reaction with the CNC surface, resulting in an aqueous solution.

[0053] Sodium citrate, sodium tripolyphosphate, polyvinyl alcohol, and xanthan gum: Add sodium citrate, sodium tripolyphosphate, polyvinyl alcohol, and xanthan gum to the remaining aqueous phase for dissolution and dispersion. Stir using a magnetic stirrer or a shaker at 500 rpm for approximately 30 minutes until all solid components are completely dissolved, yielding the second aqueous solution.

[0054] 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 aqueous phase II and 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, obtaining a mixed soap solution.

[0055] S3, Oil Phase Treatment

[0056] BHT can be added to preheated asphalt and stirred thoroughly for 30 minutes to prevent oxidation and aging of the asphalt.

[0057] S4, Emulsification process

[0058] The soap solution and heated base asphalt were passed through a colloid mill and pumped into the colloid mill for primary grinding. The grinding gap was 1.2 mm and the grinding speed was 12,000 rpm to obtain the initial emulsified asphalt solution.

[0059] During emulsification, the electric field generator is activated to apply an electric field force to the emulsion using a direct current (DC) field. Specific settings are as follows: Electric field strength: 5 kV / cm, adjustable according to emulsification requirements. Application time: The electric field force is applied continuously for 30 minutes during emulsification, adjusted according to the stability and particle size requirements of the emulsion. To further refine the emulsion particle size and improve stability, an ultrasonic processor can be used to treat the emulsion: the ultrasonic treatment time is 5 minutes, adjustable according to the viscosity and particle size of the emulsion.

[0060] S5, Post-processing

[0061] After emulsification of asphalt is completed, it should be cooled to room temperature and stored in a sealed container to avoid moisture or prolonged exposure to air, which could lead to demulsification.

[0062] Comparative Example 1

[0063] This comparative example provides a CNC-Pickering emulsified asphalt, comprising base asphalt, water, cellulose nanocrystals (CNCs), and polyvinyl alcohol, wherein the components are in the following mass fractions: 45 parts base asphalt, 50 parts deionized water, 2.5 parts cellulose nanocrystals (CNCs), and 0.5 parts polyvinyl alcohol.

[0064] Comparative Example 2

[0065] This comparative example provides a CNC-Pickering emulsified asphalt, comprising base asphalt, water, sophorolipid, and polyvinyl alcohol, wherein the components are in the following mass fractions: base asphalt 45 parts, deionized water 50 parts, sophorolipid 1.5 parts, and polyvinyl alcohol 0.5 parts.

[0066] The present invention further tests the performance of the emulsified asphalt in the examples and comparative examples, and the test indicators are storage stability, adhesion performance, compatibility, and water loss resistance. The test methods are as follows:

[0067] Storage stability: The storage stability of emulsified asphalt was tested using the storage stability test of emulsified asphalt (T0655-1993) in the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTGE20-2011).

[0068] Adhesion performance: The adhesion performance of emulsified asphalt was tested using the adhesion test between emulsified asphalt and coarse aggregate (T0654-2011) in the "Test Procedure for Asphalt and Asphalt Mixtures in Highway Engineering" (JTGE20-2011).

[0069] Water damage resistance: The water damage resistance of emulsified asphalt slurry was tested using the wet wheel abrasion test (T0752-2011) of the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTGE20-2011).

[0070] Interlayer pull-out performance: The interlayer pull-out strength of emulsified asphalt was tested using the evaluation of the tensile bond strength between the waterproof layer and concrete in Appendix N of the "Highway Engineering Quality Inspection and Evaluation Standard, Volume 1, Civil Engineering" (JTG F80 / 1—2017).

[0071] The test results are shown in Table 2.

[0072] Table 2 Test Results

[0073]

[0074] According to the data in Table 2, the bio-based modified CNC-Pickering emulsified bitumen prepared in the embodiments of the present invention exhibits excellent performance in terms of storage stability, adhesion, water damage resistance, and pull-out resistance. Comparing the results of Examples 1-9 with Comparative Examples 1-2 shows that the obtained bio-based modified CNC-Pickering emulsified bitumen generally exhibits a storage stability of less than 1.0% after 1 day and less than 2.0% after 5 days. Compared with ordinary CNC-Pickering emulsified bitumen, its storage stability is significantly improved. In the adhesion test, all bio-based modified CNC-Pickering emulsified bitumen passed the test, and the wet wheel abrasion value was less than 320 g / m² in the 1-hour test. 2 Compared to ordinary CNC-Pickering emulsified asphalt, its adhesion is significantly enhanced. Furthermore, the tensile strength is generally greater than 0.35 MPa, and its mechanical properties are also significantly improved compared to ordinary CNC-Pickering emulsified asphalt.

[0075] Based on the comparison results of Example 1 and Comparative Example 1, the CNC-Pickering emulsified asphalt prepared using CNC alone exhibited poor stability, weak adhesion, and weak mechanical properties. In contrast, the bio-based modified CNC-Pickering emulsified asphalt involved in this invention demonstrated excellent stability, mechanical properties, and adhesion. Appropriately increasing the amount of CNC can improve storage stability, adhesion, and mechanical properties to a certain extent. Based on the comparison results of Example 1 and Comparative Example 2, the emulsified asphalt prepared using sophorolipid alone had unstable storage stability, weak adhesion, and weak mechanical properties. In contrast, the CNC-Pickering emulsified asphalt of this invention overcomes these problems; appropriately increasing the amount of sophorolipid can improve storage stability to a certain extent. The comparison results of Example 1 and Example 4 show that appropriately increasing the amount of CNC and sophorolipid helps improve storage stability, adhesion, and mechanical properties. Based on the comparison of Example 1 and Example 5, moderately increasing γ-APTES can further enhance the stability of the emulsified asphalt. Through the comparison of Example 1 and Example 6, it can be found that appropriately increasing the amount of CNC, sophorolipid, and γ-APTES helps improve storage stability, adhesion, and mechanical properties. Based on the comparative results of Examples 1, 7, and 9, the appropriate addition of sodium citrate, sodium tripolyphosphate, and BHT had almost no significant effect on the stability and mechanical properties of CNC-Pickering emulsified asphalt. Finally, the comparison between Examples 1 and 8 showed that the appropriate addition of xanthan gum could significantly improve the stability of emulsified asphalt.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate 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 product comprises the following components in parts by weight: 45-55 parts base bitumen, 45-55 parts deionized water, 1-5 parts cellulose nanocrystals, 0.5-1 part γ-aminopropyltriethoxysilane, 0.5-1.5 parts sophorolipid, 0.1-0.3 parts sodium citrate, 0.1-0.3 parts sodium tripolyphosphate, 0.5-2 parts polyvinyl alcohol, 0.1-0.3 parts xanthan gum, and 0.05-0.1 parts butylated hydroxytoluene.

2. The bio-based modified CNC-Pickering emulsified asphalt according to claim 1, characterized in that: The cellulose nanocrystals are carboxylated cellulose nanocrystals (CNC), with a tensile strength of 6500-7500 MPa, Young's modulus of 100-150 GPa, crystallinity >90%, length of 150-200 nm, diameter of 3-20 nm, and 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, a white powder, with a content ≥98.0%.

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

7. The bio-based modified CNC-Pickering emulsified bitumen according to claim 1, characterized in that: The polyvinyl alcohol is a white or off-white powder or granules with a content ≥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 crystalline solid 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 bio-based modified CNC-Pickering emulsified asphalt as described in claim 1, characterized in that: Includes the following steps: S1, Preprocessing Base asphalt: Heat the base asphalt to 140℃ until it becomes fluid, avoiding excessive oxidation of the asphalt due to excessive temperature; Deionized water: Heat 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 individual nanocrystals. The ultrasonic treatment time is 30 minutes to ensure that the cellulose nanocrystals are uniformly dispersed. S2, Aqueous Phase Preparation CNC, sophorolipid, 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 add sophorolipid and stir for 60 minutes to ensure complete dispersion and full reaction with the CNC surface to obtain an aqueous solution. Sodium citrate, sodium tripolyphosphate, polyvinyl alcohol and xanthan gum: Add sodium citrate, sodium tripolyphosphate, polyvinyl alcohol and xanthan gum to the remaining deionized water, dissolve and disperse them, and stir using a magnetic stirrer or stirrer at a speed of 500 rpm for 30 minutes until all solid components are completely dissolved to obtain an aqueous phase II 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 aqueous phase II and 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 were passed through a colloid mill and pumped into the colloid mill for primary grinding. The grinding gap was 1.2 mm and the grinding speed was 12000 rpm to obtain the initial emulsified asphalt solution. During the emulsification process, the electric field generator is activated to apply an electric field force to the emulsion. A DC electric field is used, with the following settings: Electric field strength: 5 kV / cm, adjusted according to emulsification requirements; Application time: The electric field force is applied continuously for 30 minutes during the emulsification process, adjusted according to the stability and particle size requirements of the emulsion; To further refine the emulsion particle size and improve stability, an ultrasonic processor is used to treat the emulsion: The ultrasonic treatment time is 5 minutes, adjusted according to the viscosity and particle size of the emulsion; Post-processing After emulsification of asphalt is completed, it should be cooled to room temperature and stored in a sealed container to avoid moisture or prolonged exposure to air, which could lead to demulsification.

Images