A modified emulsified asphalt and its preparation method

Abstract

This invention discloses a modified emulsified asphalt and its preparation method. The modified emulsified asphalt of this invention, by weight, comprises the following components: 100 parts modified asphalt, 1.0-8.0 parts emulsifier, 0.2-1.0 parts stabilizer, and 30-100 parts water; the modified asphalt, by weight, comprises the following components: 100 parts cationic matrix asphalt, 0.5-5 parts polymer, 1-10 parts plasticizer, and 0.1-0.5 parts crosslinking agent; the cationic matrix asphalt is obtained by a chemical grafting reaction between the modifier and the matrix asphalt. This invention solves the problems of difficulty in emulsification and unstable storage of polymer-modified asphalt.

Description

Technical Field

[0001] This invention belongs to the field of asphalt modification, specifically relating to a modified emulsified asphalt and its preparation method. Background Technology

[0002] Emulsified asphalt is widely used in road construction and maintenance due to its advantages of normal-temperature construction and environmental safety. Based on this, modified emulsified asphalt, compared to ordinary emulsified asphalt, is seeing increasing demand due to its targeted improvements in high and low temperature performance and adhesion. Modified emulsified asphalt mainly includes SBR modified emulsified asphalt, rubber powder modified emulsified asphalt, and SBS modified emulsified asphalt, among others. However, each of these modified emulsified asphalts has its own shortcomings. SBR modified emulsified asphalt does not significantly improve high-temperature performance; rubber powder modified emulsified asphalt has strict requirements for the quality of the rubber powder and is prone to segregation, resulting in insufficient storage stability; SBS modified emulsified asphalt, due to its excellent high and low temperature performance, waterproof performance, rutting resistance, and ease of construction, is increasingly used in tack coats, bridge deck waterproofing tack coats, micro-surfacing, cold recycling, and cold-mix paving. However, SBS modified emulsified asphalt still faces some difficult problems, mainly high emulsification difficulty and poor storage stability. These factors restrict the large-scale promotion and application of SBS modified emulsified asphalt.

[0003] The difficulty in emulsifying SBS-modified emulsified asphalt stems primarily from the increased viscosity of the base asphalt after SBS modification compared to ordinary emulsified asphalt. This necessitates raising the temperature of the asphalt phase during emulsification, potentially resulting in the temperature of the emulsified asphalt after passing through a colloid mill exceeding the boiling point of water. Consequently, pressure must be applied at the colloid mill outlet to prevent aqueous evaporation from negatively impacting emulsification. Furthermore, the SBS particles within the asphalt must possess a sufficiently small particle size and be uniformly dispersed to reduce demulsification and improve storage stability. Currently, the common method involves preparing SBS into a latex before modifying and emulsifying the asphalt. While this method requires less sophisticated equipment, the process of preparing the SBS latex is complex and its quality is inconsistent.

[0004] To overcome the above problems, chemical grafting modification of polymers or base asphalt can be considered. This involves crosslinking and / or chemically bonding compounds with asphalt containing active functional groups, giving the asphalt surface active functional groups to facilitate subsequent SBS modification and emulsification. Currently, two methods for chemical grafting asphalt have been reported: one utilizes the -NH2 and -OH groups in the asphalt for grafting; the other utilizes the conjugated diene structure in the asphalt for DA addition to further graft. The latter generally requires a catalyst and a high-temperature, high-pressure environment.

[0005] Besides reactive polymers being used for the chemical grafting of asphalt, small molecules with active groups are also used for asphalt modification, such as dodecylbenzenesulfonic acid, thiourea dioxide, and dodecenyl succinic anhydride (DSA). Because asphaltene contains heteroatomic groups, these groups can form strongly bonded ion pairs with dodecylbenzenesulfonic acid, effectively improving the rheological and thermodynamic properties of asphalt.

[0006] Grafting asphalt with organic compounds is an effective method to improve its properties. Currently, there are two common methods for crosslinking / dispersion modification of asphalt: polymer modification, which involves mechanically dispersing a polymer modifier in molten asphalt without any chemical reaction; and bio-oil modification, which utilizes bio-oil due to its low viscosity and good compatibility with asphalt. The former requires the most vigorous dispersion conditions to achieve a homogeneous mixture, and the selected polymer should have sufficient compatibility with the asphalt binder to minimize phase separation problems during storage, transportation, application, and use. The latter method requires modification before adding most types of bio-oil to asphalt, as most types cannot be directly used as asphalt modifiers. Summary of the Invention

[0007] To address the above issues, this invention provides a modified emulsified asphalt and its preparation method. This invention solves the problems of difficulty in emulsifying and unstable storage of polymer-modified asphalt.

[0008] The first aspect of this invention provides a modified emulsified asphalt, comprising the following components by weight:

[0009]

[0010] The modified asphalt, by weight, comprises the following components:

[0011]

[0012] The cationic matrix asphalt is obtained by chemical grafting a modifier with the matrix asphalt.

[0013] Furthermore, the modifier includes modifier I and / or modifier II, and the general formulas of modifier I and modifier II are as follows:

[0014]

[0015] R1, R2, R3, R4, R5, and R6 represent organic groups.

[0016] Furthermore, each of R1, R2, R3, R4, R5, and R6 is independently selected from alkyl groups, preferably from C1 to C6. 10 Alkyl groups, more preferably selected from C1 to C5 alkyl groups.

[0017] Furthermore, based on the weight of the cationized matrix asphalt, the content of the matrix asphalt is 90wt% to 99.9wt%, and the content of the modifier is 0.1wt% to 10wt%.

[0018] Furthermore, the base asphalt is selected from one or more of vacuum residue, oxidized asphalt, and solvent-desorbed asphalt. The softening point of the base asphalt is 40–80°C.

[0019] Furthermore, the polymer is SBS and / or SIS, preferably SBS.

[0020] Furthermore, the plasticizer is one or a mixture of several of the following: extracted oil, naphthenic oil, and bio-oil.

[0021] Furthermore, the crosslinking agent is a sulfur-containing organic or inorganic compound, preferably one or more of elemental sulfur and thiamethoxam derivative compounds. The thiamethoxam derivative compounds are preferably one or more of tetramethylthiamethoxam monosulfide, tetramethylthiamethoxam disulfide, etc.

[0022] Furthermore, the emulsifier is a long-chain fatty amine cationic emulsifier, such as one or more of tallow propylene diamine, octadecyl diallyl triamine, and octadecyl propene triamine.

[0023] Furthermore, the stabilizer is one or more of calcium chloride, sodium chloride, and ammonium chloride.

[0024] A second aspect of the present invention provides a method for preparing modified emulsified asphalt, comprising:

[0025] (1) Preparation of modified asphalt;

[0026] (2) Mix the emulsifier, stabilizer and water, and adjust the pH value to obtain soap solution;

[0027] (3) The modified asphalt prepared in step (1) is mixed and emulsified with the soap solution obtained in step (2) to obtain modified emulsified asphalt.

[0028] Further, the method for preparing modified asphalt in step (1) includes:

[0029] (a) Preparation of the modifier;

[0030] (b) The base asphalt is heated and melted, mixed with the modifier, and reacted under stirring. After the reaction is completed, a halohydrocarbon is added to continue the reaction to obtain cationic base asphalt.

[0031] (c) The polymer is mixed with a plasticizer and then extruded.

[0032] (d) Mix the material formed in step (c) with the cationic matrix asphalt, add a crosslinking agent, and stir to obtain modified asphalt.

[0033] Further, in step (a), the method for preparing the modifier includes: adding a primary amine compound with a tertiary amine structure and carbon disulfide to an alkaline solution for reaction; then adding a desulfurizing agent to carry out a desulfurization reaction, and obtaining the modifier after post-treatment.

[0034] Furthermore, the primary amine compounds having a tertiary amine structure include, but are not limited to, one or more of N,N-dimethylethylenediamine, 3-(dibutylamino)propylamine, and N,N-bis(3-aminopropyl)methylamine.

[0035] Furthermore, the alkaline solution is an organic alkaline solution and / or an inorganic alkaline solution, including but not limited to one or more of triethylamine solution and K2CO3 solution.

[0036] Furthermore, the mass concentration of the alkaline solution is 5 wt% to 35 wt%. The mass-to-volume ratio of the primary ammonium compound to the alkaline solution is 1:5 to 1:45 g / mL.

[0037] Furthermore, the primary amine compound reacts with carbon disulfide at room temperature, such as 20–30°C, for 1–6 h, wherein the molar ratio of the primary amine compound to carbon disulfide is 1:1 to 1:10.

[0038] Furthermore, the desulfurizing agent is one or more of di-tert-butyl dicarbonate, sodium persulfate, and copper sulfate pentahydrate. The molar ratio of primary amine compound to desulfurizing agent is 1:1 to 1:4.

[0039] Furthermore, the temperature of the desulfurization reaction is 4℃~25℃, and the reaction time is 0.5~2h.

[0040] Furthermore, after the desulfurization reaction is completed, a modifier is obtained through post-processing. The post-processing includes washing, extraction, drying, and rotary evaporation.

[0041] The washing process can be performed using a saturated sodium chloride solution or water to remove impurities. The washing can be carried out in centrifuge tubes, with centrifugation for 5–30 minutes followed by washing. The extraction is preferably performed using ethyl acetate 2–4 times. The drying is preferably performed using anhydrous sodium sulfate. The rotary evaporation yields the modifier product.

[0042] Further, the base asphalt in step (b) is heated and melted at a temperature of 100–150°C. When the modifier is mixed with the molten base asphalt, the reaction is carried out at a temperature of 90–120°C with stirring, and the reaction time is 1–4 hours.

[0043] Further, in step (b), the haloalkane is benzyl chloride and / or hexadecane bromo.

[0044] Furthermore, the molar ratio of the modifier to the haloalkane is 1:1 to 1:5.

[0045] Furthermore, in step (b), the conditions for continuing the reaction are: reacting at 80–140°C for 1–4 hours, preferably at 100–120°C for 2–3 hours.

[0046] Furthermore, in step (c), the extrusion molding can be performed using methods conventional in the art. For example, at 150–180°C, a polymer and a plasticizer are added to the two feed ports of an extruder, respectively, followed by high-temperature extrusion, cooling, and then cutting into small particles.

[0047] Further, in step (d), after adding the crosslinking agent, the stirring conditions are: stirring at 140-180℃ for 1-5 hours to obtain modified asphalt.

[0048] Furthermore, in step (2), when preparing the soap solution, it is preferable to control the system temperature at 70–90°C. The pH value is adjusted to 2–4, and dilute hydrochloric acid is generally used to adjust the pH.

[0049] A third aspect of the present invention provides an application of modified emulsified asphalt in road construction.

[0050] Furthermore, the application specifically involves mixing the modified emulsified asphalt with aggregate for use in road construction.

[0051] Compared with the prior art, the present invention has the following advantages:

[0052] (1) The modified emulsified asphalt of the present invention is a polymer-modified emulsified asphalt that can meet the requirements of complex traffic roads.

[0053] (2) The modified emulsified asphalt of the present invention, wherein the cationic matrix asphalt is obtained by chemical grafting reaction between the modifier and the matrix asphalt. A specific modifier is used, which contains isothiocyanate groups and also contains tertiary amine structures. The modifier can achieve cross-linking / dispersion between components in the asphalt, has strong controllability, and can moderately increase the softening point of the asphalt.

[0054] (3) In the preparation method of the present invention, before preparing the modified asphalt, a suitable cationic monomer modifier is first prepared to graft the base asphalt. The modifier of the present invention contains tertiary amine and isothiocyanate groups, which makes the base asphalt more surface active, which is beneficial to crosslinking with polymers and to dispersion during subsequent preparation of emulsified asphalt, thus solving the problems of SBS modified asphalt being difficult to emulsify and unstable in storage.

[0055] (4) The modified emulsified asphalt of this invention has cationic groups grafted onto its surface, making it positively charged, while the aggregates used for paving roads are mostly negatively charged. This makes it easier for the modified emulsified asphalt to combine with the aggregates after demulsification when it is applied to cold-mixed road paving materials, increasing adhesion and anti-stripping ability, thus improving the overall performance of the mixture. Attached Figure Description

[0056] Figure 1 The modifier ITC-1 prepared in Example 1 1 H NMR spectrum;

[0057] Figure 2 The mass spectrum of the modifier ITC-1 prepared in Example 1;

[0058] Figure 3 The modifier ITC-2 prepared in Example 2 1 H NMR spectrum;

[0059] Figure 4 The mass spectrum is that of the modifier ITC-2 prepared in Example 2. Detailed Implementation

[0060] The technical solution of the present invention will be described in detail below with reference to the embodiments, but the present invention is not limited to the following embodiments. In the present invention, wt% is a mass fraction.

[0061] In this invention, the chemical structure of the modifier was characterized using a Bruker Avance II 400 nuclear magnetic resonance spectrometer (Germany) and an LTQ Orbitrap XL linear ion trap-high resolution mass spectrometer (USA).

[0062] Example 1

[0063] Preparation of Modifier ITC-1

[0064] Add 80 mL of water and 6.84 g of triethylamine to a 250 mL flask, followed by 5.96 g of N,N-dimethylethylenediamine, and begin stirring. Slowly add 7.88 g of carbon disulfide, and stir at 25 °C for 4.5 h. Cool to 4 °C in an ice bath. Add 17.72 g of di-tert-butyl dicarbonate, and stir for 1.5 h. After the desulfurization reaction is complete, wash with 25 mL of saturated sodium chloride solution to remove impurities, then extract three times with 30 mL of ethyl acetate, dry with anhydrous sodium sulfate, and finally evaporate using a rotary evaporator to obtain ITC-1. 1 See the HNMR spectrum. Figure 1 Mass spectrum (see) Figure 2 .

[0065]

[0066] Example 2

[0067] Preparation of modifier ITC-2

[0068] Add 100 mL of water, 16.3 g of K₂CO₃, and 2.9 g of N,N-bis(3-aminopropyl)methylamine sequentially to a 250 mL flask. Slowly add 9.12 g of CS₂ and stir at 25 °C for 5.5 h. Then slowly add 9.52 g of sodium persulfate and stir at 25 °C for 1 h. After the desulfurization reaction is complete, transfer the reaction mixture to a centrifuge tube, centrifuge for 15 min, wash with 30 mL of water to remove impurities, extract four times with 25 mL of ethyl acetate, dry with anhydrous sodium sulfate, and then rotary evaporate using a rotary evaporator to obtain ITC-2. 1 See the HNMR spectrum. Figure 3 Mass spectrum (see) Figure 4 .

[0069]

[0070] Example 3

[0071] 300g of petroleum asphalt with a softening point of 49.5℃ was melted at 150℃, and the modifier ITC-1 prepared above was added. The mixture was stirred mechanically at 1200 rpm at 110℃ for 4 hours. Then, 19.26g of benzyl chloride was slowly added, and the mixture was stirred continuously at 110℃ for 2 hours to obtain cationic matrix asphalt containing 5.5wt% of the modifier ITC-1.

[0072] 11.4g of SBS and 15.8g of extracted oil were added to the two feed ports of the extruder, respectively, and the mixture was extruded into strips at 160℃. After cooling, the strips were cut into small granules.

[0073] The prepared small particles were added to the prepared cationic matrix asphalt and stirred at 165°C for 0.5 h. Then, 0.15% elemental sulfur was added and stirred for 4 h to obtain the modified asphalt.

[0074] 100 mL of water was heated to 80 °C. 10 wt% hydrochloric acid was added to the hot water to adjust the pH to 2.5. Tallow propylene diamine and calcium chloride were added and mixed evenly to prepare a soap solution. Modified asphalt was heated until melted and slowly added to the prepared soap solution. The mixture was kept at 90 °C and then ground and emulsified to obtain SBS modified emulsified asphalt, wherein the content of modified asphalt was 70 wt%, the content of emulsifier was 4 wt%, the content of stabilizer was 0.2 wt%, and the content of water was 25.8 wt%.

[0075] Example 4

[0076] 300g of petroleum asphalt with a softening point of 51.6℃ was melted at 145℃. The modifier ITC-2 prepared above was added to the asphalt, and the mixture was stirred mechanically at 1400 rpm. The reaction was carried out at 115℃ for 3 hours, and then 32.45g of hexadecane bromide was slowly added. The stirring was continued, and the mixture was reacted at 120℃ for 2.5 hours to obtain cationic matrix asphalt containing 6.2wt% of the modifier ITC-2.

[0077] Add 14.5g of SBS and 20.2g of extracted oil to the two feed ports of the extruder, respectively, and extrude into strips at 170℃. After cooling, cut into small granules.

[0078] The small particles prepared above were added to the prepared cationic matrix asphalt and stirred at 175°C for 1 hour. Then, 0.12% elemental sulfur and 0.1% tetramethylthiolanthiocarbamate were added and stirred for 4 hours to obtain modified asphalt.

[0079] 80 mL of water was heated to 75 °C. 10 wt% hydrochloric acid was added to the hot water to adjust the pH to 2. Octadecyl diallyltriamine and calcium chloride were then added and stirred until homogeneous to obtain a soap solution. Modified asphalt was heated to a molten state and slowly added to the prepared soap solution. The mixture was then mixed, milled, and emulsified while maintaining a temperature of 90 °C to obtain SBS modified emulsified asphalt. The modified asphalt content was 75 wt%, the emulsifier content was 2.8 wt%, the stabilizer content was 0.4 wt%, and the water content was 21.8 wt%.

[0080] Example 5

[0081] 300g of petroleum asphalt with a softening point of 52.8℃ was melted at 150℃. The modifier ITC-1 prepared above was added to the asphalt, and the mixture was stirred mechanically at 1500 rpm. The reaction was carried out at 105℃ for 3 hours, and then 15.6g of benzyl chloride was slowly added. The reaction was continued at 115℃ for 1.5 hours to obtain cationic matrix asphalt containing 4.8wt% of the modifier ITC-1.

[0082] Add 14.7g SBS and 16.8g extracted oil to the two feed ports of the extruder respectively, extrude into strips at 175℃, and cut into small granules after cooling.

[0083] The prepared small particles were added to the prepared cationic matrix asphalt and stirred at 170°C for 0.5 h. Then, 0.22% elemental sulfur was added and stirred for 3.5 h to obtain modified asphalt.

[0084] 120 mL of water was heated to 80 °C. 10 wt% hydrochloric acid was added to the hot water to adjust the pH to 4. Tallow propylene diamine and sodium chloride were added and stirred until homogeneous to obtain a soap solution. Modified asphalt was heated until melted and slowly added to the prepared soap solution. The mixture was kept at 90 °C and then ground and emulsified to obtain SBS modified emulsified asphalt, wherein the content of modified asphalt was 68 wt%, the content of emulsifier was 4.2 wt%, the content of stabilizer was 0.4 wt%, and the content of water was 27.4 wt%.

[0085] Example 6

[0086] 300g of petroleum asphalt with a softening point of 55.6℃ was melted at 150℃. The modifier ITC-2 prepared above was added to the asphalt, and the mixture was stirred mechanically at 1600 rpm. The reaction was carried out at 115℃ for 3 hours, and then 19.5g of benzyl chloride was slowly added. The reaction was continued at 110℃ for 2 hours to obtain cationic matrix asphalt containing 6.0wt% of the modifier ITC-2.

[0087] Add 16.8g of SBS and 23.1g of extracted oil to the two feed ports of the extruder, respectively, and extrude into strips at 175℃. After cooling, cut into small granules.

[0088] The prepared small particles were added to the prepared cationic matrix asphalt and stirred at 180°C for 0.5 h. Then, 0.18% elemental sulfur and 0.12% tetramethylthiolanthiocarbamate monosulfide were added and stirred for 4 h to obtain modified asphalt.

[0089] 85 mL of water was heated to 85 °C. 10 wt% hydrochloric acid was added to the hot water to adjust the pH to 3. Tallow propylene diamine and sodium chloride were added and stirred until homogeneous to obtain a soap solution. Modified asphalt was heated until melted and slowly added to the prepared soap solution. The mixture was kept at 85 °C and then ground and emulsified to obtain SBS modified emulsified asphalt. The modified asphalt content was 74 wt%, the emulsifier content was 3.6 wt%, the stabilizer content was 0.3 wt%, and the water content was 22.1 wt%.

[0090] Comparative Example 1

[0091] 14.5g of SBS and 20.2g of extracted oil were added to the two feed ports of an extruder, respectively, and extruded into strips at 170℃. After cooling, the strips were cut into small granules. The granules were added to 300g of molten petroleum asphalt with a softening point of 51.6℃, and stirred at 175℃ for 1 hour. Then, 0.12% of elemental sulfur and 0.1% of tetramethylthiol disulfide were added, and the mixture was stirred for 4 hours to obtain SBS-modified asphalt.

[0092] 80 mL of water was heated to 75 °C. 10 wt% hydrochloric acid was added to the hot water to adjust the pH to 2. Octadecyl diallyltriamine and calcium chloride were then added and stirred until homogeneous to obtain a soap solution. SBS-modified asphalt was heated to a molten state and slowly added to the prepared soap solution. The mixture was then mixed, milled, and emulsified while maintaining a temperature of 90 °C to obtain SBS-modified emulsified asphalt. The asphalt content was 75 wt%, the emulsifier content was 2.8 wt%, the stabilizer content was 0.4 wt%, and the water content was 21.8 wt%.

[0093] Comparative Example 2

[0094] 300g of petroleum asphalt with a softening point of 51.6℃ was melted at 145℃. The modifier ITC-2 prepared above was added to the asphalt, and the mixture was stirred mechanically at 1400 rpm. The reaction was carried out at 115℃ for 3 hours to obtain cationic matrix asphalt containing 6.2 wt% of the modifier ITC-2.

[0095] Add 14.5g of SBS and 20.2g of extracted oil to the two feed ports of the extruder, respectively, and extrude into strips at 170℃. After cooling, cut into small granules.

[0096] The small particles prepared above were added to the prepared cationic matrix asphalt and stirred at 175°C for 1 hour. Then, 0.12% elemental sulfur and 0.1% tetramethylthiolanthiocarbamate were added and stirred for 4 hours to obtain cationic SBS modified asphalt.

[0097] 80 mL of water was heated to 75 °C. 10 wt% hydrochloric acid was added to the hot water to adjust the pH to 2. Octadecyl diallyltriamine and calcium chloride were then added and stirred until homogeneous to obtain a soap solution. SBS modified asphalt was heated to a molten state and slowly added to the prepared soap solution. The mixture was then mixed, milled, and emulsified while maintaining a temperature of 90 °C to obtain SBS modified emulsified asphalt. The asphalt contained 75 wt% modified asphalt, 2.8 wt% emulsifier, 0.4 wt% stabilizer, and 21.8 wt% water.

[0098] Preparation of modified emulsified asphalt mixture: According to the AC-10 aggregate gradation, 10% of the SBS modified emulsified asphalt prepared in Examples 3-6 and Comparative Examples 1-2 was added. Before mixing the emulsified asphalt mixture, 1% cement was added and dry-mixed with the aggregate for 60 seconds. Then, the modified emulsified asphalt was added and mixed for 90 seconds to complete the mixing. Marshall specimens were formed by compacting each side 50 times. Without demolding, the specimens were accelerated to 24 hours in a 105℃ environmental chamber. After cooling, the Marshall specimens were compacted again on each side 25 times to complete the specimen preparation.

[0099] The properties of the modified asphalt and the modified emulsified asphalt mixtures obtained in the above embodiments are shown in Tables 1 and 2, respectively. The data in Table 1 show that the softening point of the asphalt increased and it acquired positive charge after modification with the cationic monomer modifier. The data in Table 2 indicate that the emulsified asphalt mixture prepared using this modifier exhibits enhanced performance.

[0100] Table 1. Properties of modified asphalt in the examples and comparative examples.

[0101] nature Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 Softening point / °C 88.3 91.4 85.8 94.6 82.5 84.8 Viscosity / Nm 27.5 30.2 31.4 29.9 20.3 23.5 Zeta potential / mV +26.6 +29.7 +28.4 +30.5 - +12.8

[0102] Table 2 Properties of modified emulsified asphalt mixtures in the examples and comparative examples

[0103]

[0104]

[0105] *Note: Comparative Example 1 showed emulsification failure.

Claims

1. A modified emulsified asphalt characterized by, The modified emulsified asphalt comprises the following components in parts by weight: Modified asphalt 100 parts, Emulsifier 1.0-8.0 parts, Stabilizer 0.2-1.0 parts, Water 30-100 parts. The modified asphalt comprises the following components in parts by weight: Cationized base asphalt 100 parts, High molecular polymer 0.5-5 parts, Plasticizer 1-10 parts, Crosslinking agent 0.1-0.5 parts. The cationized base asphalt is obtained by chemical grafting reaction of a modifier and base asphalt. The modifier comprises modifier I and / or modifier II, and the general formulae of the modifier I and the modifier II are as follows: ； In the formulae, R1, R2, R3, R4, R5 and R6 represent organic groups. R1, R2, R3, R4, R5, and R6 are each independently selected from C1 to C2. 10 alkyl.

2. The modified emulsified asphalt according to claim 1, characterized by, R1, R2, R3, R4, R5 and R6 are each independently selected from C1-C5 alkyl groups.

3. The modified emulsified asphalt according to claim 1, characterized by, The content of the base asphalt is 90wt%-99.9wt% and the content of the modifier is 0.1wt%-10wt% based on the weight of the cationized base asphalt.

4. The modified emulsified asphalt according to claim 1, characterized by The base asphalt is selected from one or more of vacuum residue, oxidized asphalt and deasphalted oil, and the softening point of the base asphalt is 40-80℃.

5. The modified emulsified asphalt according to claim 1, characterized by The high molecular polymer is SBS and / or SIS.

6. The modified emulsified asphalt according to claim 1, characterized by, The plasticizer is a mixture of one or more of extracted oil, naphthenic oil and bio-oil.

7. The modified emulsified asphalt according to claim 1, characterized by The crosslinking agent is an organic or inorganic sulfur-containing compound.

8. The modified emulsified asphalt according to claim 7, characterized by, The crosslinking agent is one or more of elemental sulfur and thiolane compounds.

9. The modified emulsified asphalt according to claim 8, characterized by The thiolane compound is one or more of tetramethyl monosulfide and tetramethyl disulfide.

10. The modified emulsified asphalt according to claim 1, characterized by, The emulsifier is a long-chain fatty amine cationic emulsifier.

11. The modified emulsified asphalt according to claim 10, characterized in that, The emulsifier is one or more of tallow propylene diamine, octadecyl dipropylene triamine and octadecyl propylene triamine.

12. The modified emulsified asphalt according to claim 1, characterized by, The stabilizer is one or more of calcium chloride, sodium chloride and ammonium chloride.

13. The method of preparing a modified emulsified asphalt according to any one of claims 1 to 12, characterized in that, The method comprises the following steps: (1) preparing modified asphalt; (2) mixing the emulsifier, the stabilizer and water, adjusting the pH value, and obtaining a soap solution; (3) mixing and emulsifying the modified asphalt prepared in step (1) and the soap solution obtained in step (2), and obtaining modified emulsified asphalt.

14. The method of claim 13, wherein, The method for preparing the modified asphalt in step (1) comprises the following steps: (a) preparing a modifier; (b) heating and melting the base asphalt, mixing the base asphalt with the modifier, and reacting under stirring, then adding a halogenated hydrocarbon to continue the reaction, and obtaining cationized base asphalt; (c) mixing the high molecular polymer and the plasticizer, and extruding and shaping; (d) mixing the shaped material in step (c) with the cationized base asphalt, adding the crosslinking agent, and stirring, and obtaining modified asphalt.

15. The method of claim 14, wherein, The method for preparing the modifier in step (a) comprises the following steps: adding a primary amine compound with a tertiary amine structure and carbon disulfide in an alkaline solution to react; then adding a desulfurizer to perform desulfurization reaction, and obtaining the modifier after post-treatment.

16. The method of claim 15, wherein, The primary amine compound with a tertiary amine structure is one or more of N,N-dimethylethylenediamine, 3-(dibutylamino)propylamine and N,N-bis(3-aminopropyl)methylamine.

17. The method of claim 15, wherein, The basic solution is an organic basic solution and / or an inorganic basic solution, the mass concentration of the basic solution is 5wt%-35wt%; and / or, the mass-volume ratio of the primary amine compound to the basic solution is 1:5-1:45g / mL.

18. The method of claim 17, wherein, The basic solution is one or more of triethylamine solution, K2CO3 solution.

19. The method of claim 15, wherein, The reaction of the primary amine compound with carbon disulfide is carried out at 20-30℃, and the reaction time is 1-6h; and / or, the molar ratio of the primary amine compound to carbon disulfide is 1:1-1:

10.

20. The method of claim 15, wherein, The desulfurizer is one or more of di-tert-butyl dicarbonate, sodium persulfate, and copper sulfate pentahydrate; and the molar ratio of the primary amine compound to the desulfurizer is 1:1-1:

4.

21. The method of claim 15, wherein, The temperature of the desulfurization reaction is 4℃-25℃, and the reaction time is 0.5-2h.

22. The method of claim 14, wherein, In step (b), when the modifier is mixed with the molten base pitch, the reaction is carried out under stirring at a temperature of 90-120℃, and the reaction time is 1-4h.

23. The method of claim 14, wherein, In step (b), the halogenated hydrocarbon is benzyl chloride and / or bromohexadecane; and / or, the molar ratio of the modifier to the halogenated hydrocarbon is 1:1-1:

5.

24. The method of claim 14, wherein, In step (b), the conditions for continuing the reaction are: 80-140℃ for 1-4h.

25. The method of claim 24, wherein, In step (b), the conditions for continuing the reaction are: 100-120℃ for 2-3h.

26. The method of claim 14, wherein, In step (d), after the crosslinking agent is added, the stirring conditions are: stirring at 140-180℃ for 1-5h to obtain the modified pitch.

27. The method of claim 13, wherein, In step (2), when the soap solution is prepared, the system temperature is controlled to be 70-90℃; and the pH value is 2-4.

28. The use of the modified emulsified pitch according to any one of claims 1-12 or prepared according to the method of any one of claims 13-27 in road construction.

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