Modified emulsified asphalt and preparation method thereof

Abstract

The invention discloses modified emulsified asphalt and a preparation method thereof. The modified emulsified asphalt disclosed by the invention is prepared from the following components in parts by weight: 100 parts of modified asphalt, 1.0 to 8.0 parts of an emulsifier, 0.2 to 1.0 part of a stabilizer and 30 to 100 parts of water, the modified asphalt is prepared from the following components in parts by weight: 100 parts of cationized matrix asphalt, 0.5 to 5 parts of a high-molecular polymer, 1 to 10 parts of a plasticizer and 0.1 to 0.5 part of a cross-linking agent, the cationized matrix asphalt is obtained by carrying out chemical grafting reaction on a modifier and activated matrix asphalt. The problems that high-molecular polymer modified asphalt is difficult to emulsify and unstable to store are solved.

Description

Technical Field

[0001] The present invention belongs to the field of asphalt modification, and particularly relates to a modified emulsified asphalt and a preparation method thereof. Background Art

[0002] Due to the characteristics of normal-temperature construction, environmental protection and safety, emulsified asphalt is widely used in road construction and maintenance. On this basis, compared with ordinary emulsified asphalt, the former has gradually increased demand because it specifically improves the high and low temperature performance, adhesion, etc. Modified emulsified asphalt mainly includes SBR modified emulsified asphalt, crumb rubber modified emulsified asphalt, SBS modified emulsified asphalt, and so on. SBS modified emulsified asphalt is increasingly applied to tack coats, waterproof bonding layers on bridge decks, microsurfacing, cold recycling, cold mixing and cold paving, etc. due to its excellent high and low temperature performance, waterproof performance, rutting resistance performance and construction convenience. However, there are still some problems that are difficult to solve in SBS modified emulsified asphalt, mainly high emulsification difficulty and poor storage stability, which restrict the large-scale popularization and application of SBS modified emulsified asphalt.

[0003] The reason why SBS modified emulsified asphalt is difficult to emulsify is mainly that compared with ordinary emulsified asphalt, the viscosity of the base asphalt becomes larger after being modified by SBS. Therefore, during the emulsification process, the temperature of the asphalt phase needs to be increased, resulting in the temperature of the emulsified asphalt after passing through the colloid mill may be greater than the boiling point of water. Therefore, pressure needs to be applied at the outlet of the colloid mill to avoid the evaporation of the water phase and affect the emulsification effect. And the SBS particles in the asphalt must have a small enough particle size and be evenly dispersed to reduce the demulsification rate and improve the storage stability. Currently, the common method is to prepare SBS into a latex and then modify and emulsify the asphalt. This emulsification method has low requirements for equipment, but the process for preparing SBS latex is complex and the quality is also unstable.

[0004] To overcome the above problems, chemical graft modification of polymers or base asphalt with active compounds can be considered, that is, compounds with active functional groups crosslink and / or chemically bond with asphalt, so that the surface of the asphalt has active functional groups, which is beneficial to subsequent SBS modification and emulsification. There are two reported methods for chemically grafting asphalt at present. One is to use -NH 2 and -OH in asphalt for grafting; the other is to use the conjugated diene structure in asphalt for D-A addition to further graft. The latter generally requires a catalyst and a high temperature and high pressure environment.

[0005] In addition to the chemical grafting of reactive polymers onto asphalt, small molecules with active groups have also been used for asphalt modification, such as dodecylbenzenesulfonic acid, thiourea dioxide, and dodecenyl succinic anhydride (DSA). Since asphaltenes contain heteroatom groups, they can form ion pairs with strong bonding interactions with dodecylbenzenesulfonic acid, which can effectively improve the rheological and thermodynamic properties of asphalt.

[0006] Grafting modification of asphalt with organic compounds is an effective method to improve the properties of asphalt. Currently, there are two common methods for crosslinking / dispersing modification of asphalt. One is polymer modification, that is, mechanically dispersing the polymer modifier in molten asphalt without chemical reactions occurring; the other is bio-oil modification. Since bio-oil has a low viscosity and good compatibility with asphalt, it can be used as a modifier. The former requires as intense dispersion conditions as possible to make it a homogeneous mixture, and the selected polymer should have sufficient compatibility with the asphalt binder to reduce phase separation problems during storage, transportation, application, and use. For the latter, since most types of bio-oil cannot be directly used as an asphalt modifier, it needs to be modified before being added to asphalt. Summary of the Invention

[0007] Aiming at the deficiencies of the prior art, the present invention provides a modified emulsified asphalt and its preparation method. The present invention solves the problems of difficult emulsification and unstable storage of polymer-modified asphalt.

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

[0009]

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

[0011]

[0012]

[0013] The cationized matrix asphalt is obtained by a chemical grafting reaction of a modifier with the activated matrix asphalt.

[0014] Furthermore, the preparation method of the modifier includes: first, obtaining a cyclic monomer by reacting a nitrile monomer under the action of a catalyst; then, subjecting the above cyclic monomer to ring-opening polymerization to form a polymer of the cyclic monomer; finally, hydrolyzing the polymer of the cyclic monomer under acidic conditions to obtain the modifier. The specific method includes:

[0015] (a) Adding the nitrile monomer and the catalyst to a reactor, heating to 90 - 120 °C, then adding the amino alcohol monomer, and reacting for 30 - 60 h to obtain the cyclic monomer;

[0016] (b) Mix the cyclic monomer obtained in step (a), the initiator and the nitrile monomer, react at 100 - 160 °C for 30 - 90 min, then add a methanol solution of KOH at -10 °C - 10 °C, stir for 8 - 24 h, remove the solvent, dissolve the residual polymer in chloroform, precipitate and purify, and dry to obtain the polymer of the cyclic monomer.

[0017] (c) Dissolve the polymer of the cyclic monomer obtained in step (b) in hot water, heat under reflux, add a hydrochloric acid solution, react for 24 - 72 h, remove the solvent, redissolve the residual polymer in hot water, add a NaOH solution until the pH value of the solution is 9 - 10, precipitate by centrifugation, remove the supernatant, repeat 2 - 3 times, and dry to obtain the modifier.

[0018] Further, in step (a), the nitrile monomer is preferably ultra-dry acetonitrile and / or propionitrile. The catalyst is zinc acetate dihydrate. Among them, the volume-mass ratio of the nitrile monomer to the catalyst addition amount is 10 - 20∶1 mL / g. The amino alcohol monomer is preferably one or more of 2-aminoethanol and 3-amino-1-propanol. The volume ratio of the nitrile monomer to the amino alcohol monomer addition amount is 1∶1 - 3.

[0019] Further, in step (b), the initiator is a sulfonate cationic initiator, preferably one or more of methyl p-toluenesulfonate (MeOTs), ethyl trifluoromethanesulfonate, 3-butynyl p-toluenesulfonate, etc. In step (b), the nitrile monomer is preferably ultra-dry acetonitrile and / or propionitrile. Among them, the nitrile monomer in step (b) can be the same as or different from that in step (a). In step (b), the volume ratio of the initiator to the cyclic monomer addition amount is 0.01 - 0.1∶1; the volume ratio of the cyclic monomer to the nitrile monomer is 1∶1 - 3.

[0020] Further, in step (b), after mixing the cyclic monomer, the initiator and the nitrile monomer, the reaction is carried out in a microwave reactor.

[0021] Further, in step (b), the concentration of KOH in the methanol solution of KOH is 0.8 - 1.2 mol / L. The addition amount of the methanol solution of KOH is 1 / 10 - 1 / 40 of the volume of the cyclic monomer.

[0022] Further, in step (b), the stirring is carried out at 20 - 30 °C, preferably at room temperature.

[0023] Further, in step (b), the solvent can be removed by rotary evaporation. The precipitation and purification can be carried out in n-hexane. The drying conditions are: drying in vacuo at 30 - 50 °C for 24 - 72 h.

[0024] Further, in step (c), the temperature of the hot water is 40 - 80 °C. The temperature of the heating reflux is 80 - 120 °C, and the time of the heating reflux is 10 - 30 min. The mass concentration of the hydrochloric acid solution is 30% - 38%. The mass ratio of the addition amount of the hydrochloric acid solution to the addition amount of the polymer of the cyclic monomer is 1 - 20:1. The solvent can be removed by rotary evaporation. The drying conditions are: vacuum drying at 50 - 70 °C for 24 - 72 h.

[0025] Further, the activated matrix asphalt is prepared by reacting matrix asphalt with organic anhydride. Further, the matrix asphalt is selected from one or more of petroleum asphalt and natural asphalt. The softening point of the matrix asphalt is 30 °C - 70 °C.

[0026] Further, the organic anhydride is a mono - or poly - basic organic anhydride, preferably selected from one or more of maleic anhydride, polyethylene glycol anhydride, polyglutaric anhydride, polynonanoic anhydride, and polyisobutylene succinic anhydride.

[0027] Further, the polymer is SBS and / or SIS, preferably SBS.

[0028] Further, the plasticizer is one or more of extraction oil, naphthenic oil, and bio - oil.

[0029] Further, the cross - linker is a sulfur - containing organic and / or inorganic substance, preferably one or more of elemental sulfur and thiuram compounds. Among them, the thiuram compounds are preferably one or more of tetramethylthiuram monosulfide and tetramethylthiuram disulfide.

[0030] Further, the emulsifier is a long - chain fatty amine - type cationic emulsifier, preferably one or more of tallow propylene diamine, octadecyl dipropylene triamine, octadecyl propylene triamine, etc.

[0031] Further, the stabilizer is one or more of calcium chloride, sodium chloride, and ammonium chloride.

[0032] The second aspect of the present invention provides a preparation method of modified emulsified asphalt, including:

[0033] (I) Prepare modified asphalt;

[0034] (II) Mix the emulsifier, stabilizer with water, and adjust the pH value to obtain a soap solution;

[0035] (III) Mix and emulsify the modified asphalt prepared in step (I) with the soap solution obtained in step (II) to obtain modified emulsified asphalt.

[0036] Further, the method for preparing the modified asphalt in step (I) includes:

[0037] (1) Prepare a modifier;

[0038] (2) Prepare an activated matrix asphalt;

[0039] (3) Heat and melt the activated matrix asphalt, mix it with the modifier, carry out a reaction under stirring, and after the reaction is completed, add a halogenated hydrocarbon to continue the reaction to obtain a cationized matrix asphalt;

[0040] (4) Mix a polymer with a plasticizer and carry out extrusion molding;

[0041] (5) Mix the material obtained from step (4) after molding with the cationized matrix asphalt, and add a crosslinking agent, and stir to obtain a modified asphalt.

[0042] Further, in step (2), the method for preparing the activated matrix asphalt includes: heating the base asphalt to a molten state, adding an organic anhydride accounting for 2%-20% of the weight of the base asphalt, and introducing an inert gas to keep the pressure in the asphalt reaction kettle at 0.2-2.0 MPa, the reaction temperature is 150-250 °C, and the reaction time is 2-8 hours to obtain the activated matrix asphalt. During the reaction, it is preferred to add an initiator. The initiator is at least one of azobisisobutyronitrile and dicumyl peroxide. The mass ratio of the initiator to the organic anhydride is 1:5-10.

[0043] Further, in step (3), heat and melt the activated matrix asphalt, mix it with the modifier, and carry out a reaction under stirring. The rotation speed of the stirring is 80-2000 rpm. The conditions for the reaction are: the reaction temperature is 50-120 °C, and the reaction time is 2-10 h.

[0044] Further, in step (3), the addition amount of the modifier is 0.5%-10% of the mass of the activated matrix asphalt.

[0045] Further, in step (3), the halogenated hydrocarbon is benzyl chloride and / or cetyl bromide.

[0046] Further, the mass ratio of the modifier to the halogenated hydrocarbon is 1-3:1.

[0047] Further, in step (3), the conditions for adding the halogenated hydrocarbon to continue the reaction are: reacting at 80-140 °C for 1-4 h, preferably reacting at 100-120 °C for 2-3 h.

[0048] Further, in step (4), the extrusion molding can be carried out by a conventional method in the art. For example, at 150-180 °C, add a polymer and a plasticizer to the two feed ports of an extruder respectively, carry out high-temperature extrusion, and cut into small particles after cooling, with an average particle size less than 5 mm, preferably 1-4.5 mm.

[0049] Further, in step (5), after adding the cross-linking agent, the stirring conditions are: stirring at 140 - 180°C for 1 - 5 h to obtain the modified asphalt.

[0050] Further, in step (II), when preparing the soap solution, it is preferred to control the system temperature at 70 - 90°C. The pH value is adjusted to 2 - 4, and dilute hydrochloric acid can be used to adjust the pH.

[0051] Further, in step (III), the modified asphalt prepared in step (I) is first heated and melted, and then mixed and emulsified with the soap solution obtained in step (II). The emulsification temperature is: 70 - 90°C.

[0052] The third aspect of the present invention provides an application of the modified emulsified asphalt in road construction.

[0053] Further, the application specifically is to mix the modified emulsified asphalt with the stone materials for road construction.

[0054] Compared with the prior art, the present invention has the following advantages:

[0055] (1) The modified emulsified asphalt of the present invention is a polymer - modified emulsified asphalt, which can meet the use requirements of complex traffic roads.

[0056] (2) In the modified emulsified asphalt of the present invention, the cationic matrix asphalt is obtained by a chemical grafting reaction of a specific modifier with the activated matrix asphalt, making the matrix asphalt have higher surface activity, which is beneficial for both cross - linking with the polymer and dispersion during the subsequent preparation of emulsified asphalt, solving the problems of difficult emulsification and unstable storage of SBS - modified asphalt.

[0057] (3) The modified emulsified asphalt of the present invention is grafted with cationic groups on its surface and is positively charged, while the stone materials used for paving roads are mostly negatively charged. When this modified emulsified asphalt is applied to cold - laid and cold - mixed road mixtures, after demulsification, the modified asphalt therein is easy to combine with the stone materials, increasing the adhesion and anti - stripping ability, and improving the overall use performance of the mixture. Specific Embodiments

[0058] The technical solutions 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 the mass fraction.

[0059] Example 1

[0060] Preparation of Modifier I

[0061] 37.4 mL of ultradry acetonitrile and 3.65 g of zinc acetate dihydrate were added to a 250 mL three-necked flask, and the mixture was heated to 115 °C. After the acetonitrile refluxed, 58 mL of 2-aminoethanol was slowly added dropwise thereto using a constant-pressure dropping funnel, and the reaction was carried out for 54 h. After impurity removal, a cyclic monomer was obtained. 28.2 mL of the above cyclic monomer, 0.48 mL of methyl p-toluenesulfonate (MeOTs), and 49.5 mL of ultradry acetonitrile were mixed, placed in a microwave reactor at 145 °C for 60 min, and then 0.86 mL of a methanol solution of KOH with a concentration of 0.8 mol / L was added at 4 °C, and the mixture was stirred at room temperature for 15 h to terminate the polymerization. The solvent was removed by rotary evaporation, the residual polymer was dissolved in chloroform and then precipitated and purified 3 times in n-hexane, and dried in vacuo at 45 °C for 58 h to obtain a polymer of the cyclic monomer. 26.6 g of the above cyclic monomer polymer was dissolved in hot water at 65 °C, heated to reflux at 110 °C for 20 min, added to 280 g of hydrochloric acid with a mass concentration of 36%, and the reaction was carried out for 45 h. The solvent was removed by rotary evaporation, the residual solid was redissolved in hot water at 65 °C, and the solution was neutralized with NaOH solution to pH = 9. The precipitated precipitate was centrifuged, and the supernatant was discarded. This was repeated 3 times, and dried in vacuo at 60 °C for 48 h to obtain modifier I.

[0062] Example 2

[0063] Preparation of modifier II

[0064] 49.6 mL of ultradry propionitrile and 4.28 g of zinc acetate dihydrate were added to a 250 mL three-necked flask, and the mixture was heated to 120 °C. After the propionitrile refluxed, 88 mL of 3-amino-1-propanol was slowly added dropwise thereto using a constant-pressure dropping funnel, and the reaction was carried out for 48 h. After impurity removal, a cyclic monomer was obtained. 32.5 mL of the above cyclic monomer, 0.6 mL of 3-butynyl p-toluenesulfonate, and 55.8 mL of ultradry propionitrile were mixed, placed in a microwave reactor at 155 °C for 75 min, and then 1.8 mL of a methanol solution of KOH with a concentration of 1 mol / L was added at 2 °C, and the mixture was stirred at room temperature for 22 h to terminate the polymerization. The solvent was removed by rotary evaporation, the residual polymer was dissolved in chloroform and then precipitated and purified 3 times in n-hexane, and dried in vacuo at 40 °C for 50 h to obtain a polymer of the cyclic monomer. 31.2 g of the above cyclic monomer polymer was dissolved in hot water at 70 °C, heated to reflux at 115 °C for 30 min, added to 350 g of hydrochloric acid with a mass concentration of 37%, and the reaction was carried out for 36 h. The solvent was removed by rotary evaporation, the residual solid was redissolved in hot water at 70 °C, and the solution was neutralized with NaOH solution to pH = 9.5. The precipitated precipitate was centrifuged, and the supernatant was discarded. This was repeated 3 times, and dried in vacuo at 65 °C for 50 h to obtain modifier II.

[0065] Example 3

[0066] 300 g of vacuum residue with a softening point of 40.6 °C was heated to the molten state in a reaction kettle, 25.3 g of maleic anhydride and 4.5 g of azodiisobutyronitrile were added, and N 2 The pressure in the reaction kettle was maintained at 1.0 MPa, and the reaction was carried out at 150 °C for 4.5 hours to obtain activated matrix asphalt. 26.2 g of the modifier I prepared above was added to the activated matrix asphalt in the molten state, and mechanical stirring was carried out at a rotation speed of 1200 rpm. The stirring reaction was carried out at 110 °C for 4 h, then 14.25 g of benzyl chloride was slowly added, and stirring was continued. The reaction was carried out at 110 °C for 2 h to obtain cationized matrix asphalt.

[0067] 13.4 g of SBS and 17.8 g of extracted oil were respectively added to the two feed ports of the extruder, and extruded into strips at 160 °C. After cooling, they were cut into small particles with an average particle size of 3 mm.

[0068] The small particles prepared above were added to the prepared cationized matrix asphalt, stirred at 165 °C for 0.5 h, 0.15% of elemental sulfur was added, and stirred for 4 h to obtain modified asphalt.

[0069] 100 mL of water was heated to 80 °C, hydrochloric acid with a mass concentration of 10 wt% was added to the hot water, the pH was adjusted to 3.0, tallow propylene diamine and calcium chloride were added, and stirred evenly to prepare a soap solution; the modified asphalt was heated to the molten state and slowly added to the prepared soap solution, and mixed and ground at 90 °C for emulsification to obtain modified emulsified asphalt. Among them, the content of modified asphalt was 70 wt%, the content of emulsifier was 4.2 wt%, the content of stabilizer was 0.2 wt%, and the content of water was 25.6 wt%.

[0070] Example 4

[0071] 300 g of petroleum asphalt with a softening point of 43.2 °C was heated to the molten state in a reaction kettle, 32.5 g of polyisobutylene succinic anhydride and 3.7 g of diisopropylbenzene peroxide were added, and N 2 The pressure in the reaction kettle was maintained at 0.8 MPa, and the reaction was carried out at 155 °C for 5.0 hours to obtain activated matrix asphalt. 29.2 g of the modifier II prepared above was added to the activated matrix asphalt in the molten state, and mechanical stirring was carried out at a rotation speed of 1600 rpm. The stirring reaction was carried out at 115 °C for 3.5 h, then 22.65 g of cetyl bromide was slowly added, and stirring was continued. The reaction was carried out at 120 °C for 3 h to obtain cationized matrix asphalt.

[0072] 14.5 g of SBS and 20.2 g of extracted oil were respectively added to the two feed ports of the extruder, and extruded into strips at 170 °C. After cooling, they were cut into small particles with an average particle size of 2 mm.

[0073] Add the prepared small particles to the prepared cationized matrix asphalt, stir at 170 °C for 1 h, add 0.1% elemental sulfur and 0.12% tetramethylthiuram disulfide, and stir for 3.5 h to obtain the modified asphalt.

[0074] Heat 80 mL of water to 75 °C, add hydrochloric acid with a mass concentration of 10 wt% to the hot water, adjust the pH to 2.5, add octadecyl dipropylene triamine and calcium chloride, and stir evenly to prepare a soap solution; heat the modified asphalt to melting and slowly add the prepared soap solution, and keep mixing and grinding and emulsifying at 90 °C to obtain the modified emulsified asphalt. Among them, the content of the modified asphalt is 75 wt%, the content of the emulsifier is 2.8 wt%, the content of the stabilizer is 0.4 wt%, and the content of water is 21.8 wt%.

[0075] Example 5

[0076] Heat 300 g of petroleum asphalt with a softening point of 48.8 °C to the molten state in a reaction kettle, add 21.2 g of glutaric anhydride and 3.4 g of azobisisobutyronitrile, and introduce N 2 Keep the pressure of the reaction kettle at 1.4 MPa and react at 165 °C for 6 hours to obtain the activated matrix asphalt. Add 28.6 g of the above-prepared modifier I to the activated matrix asphalt in the molten state, and stir with a mechanical stirrer at a rotation speed of 1400 rpm. Stir and react at 110 °C for 3 h, then slowly add 17.0 g of benzyl chloride, and continue to stir and react at 115 °C for 2 h to obtain the cationized matrix asphalt.

[0077] Add 17.7 g of SBS and 19.8 g of extracted oil to the two feed ports of the extruder respectively, extrude into strips at 175 °C, and cut into small particles with an average particle size of 4 mm after cooling.

[0078] Add the prepared small particles to the prepared cationized matrix asphalt, stir at 170 °C for 0.5 h, add 0.25% elemental sulfur, and stir for 4 h to obtain the modified asphalt.

[0079] Heat 120 mL of water to 80 °C, add hydrochloric acid with a mass concentration of 10 wt% to the hot water, adjust the pH to 3.5, add tallow propylene diamine and sodium chloride, and stir evenly to prepare a soap solution; heat the modified asphalt to melting and slowly add the prepared soap solution, and keep mixing and grinding and emulsifying at 85 °C to obtain the modified emulsified asphalt. Among them, the content of the modified asphalt is 68 wt%, the content of the emulsifier is 3.6 wt%, the content of the stabilizer is 0.4 wt%, and the content of water is 28 wt%.

[0080] Example 6

[0081] Heat 300 g of petroleum asphalt with a softening point of 52.2 °C to a molten state in a reaction kettle, add 38.5 g of maleic anhydride and 4.2 g of azobisisobutyronitrile, and introduce N 2 Keep the pressure in the reaction kettle at 1.6 MPa and react at 160 °C for 5.5 hours to obtain activated matrix asphalt. Add 27.8 g of the modifier II prepared above to the molten activated matrix asphalt and stir using mechanical stirring at a rotation speed of 1800 rpm. Stir and react at 120 °C for 3.5 h, then slowly add 20.5 g of benzyl chloride and continue stirring and reacting at 110 °C for 2.5 h to obtain cationic matrix asphalt.

[0082] Add 18.8 g of SBS and 24.2 g of extracted oil to the two feed ports of an extruder respectively, extrude into strips at 180 °C, and cut into small particles with an average particle size of 3.5 mm after cooling.

[0083] Add the small particles prepared above to the prepared cationic matrix asphalt, stir at 180 °C for 0.5 h, add 0.15% of elemental sulfur and 0.15% of tetramethylthiuram monosulfide, and stir for 4 h to obtain modified asphalt.

[0084] Heat 85 mL of water to 85 °C, add hydrochloric acid with a mass concentration of 10 wt% to the hot water, adjust the pH to 3.5, add tallow propylene diamine and sodium chloride, and stir evenly to prepare a soap solution; heat the modified asphalt to a molten state and slowly add the prepared soap solution, and keep mixing and grinding at 85 °C for emulsification to obtain modified emulsified asphalt. Among them, the content of modified asphalt is 73 wt%, the content of emulsifier is 3.5 wt%, the content of stabilizer is 0.3 wt%, and the content of water is 23.2 wt%.

[0085] Comparative Example 1

[0086] Add 18.8 g of SBS and 24.2 g of extracted oil to the two feed ports of an extruder respectively, extrude into strips at 180 °C, and cut into small particles with an average particle size of 3.5 mm after cooling.

[0087] Add the small particles prepared above to 300 g of molten petroleum asphalt with a softening point of 52.2 °C, stir at 180 °C for 0.5 h, add 0.15% of elemental sulfur and 0.15% of tetramethylthiuram monosulfide, and stir for 4 h to obtain modified asphalt.

[0088] Heat 85 mL of water to 85 °C. Add hydrochloric acid with a mass concentration of 10 wt% to the hot water, adjust the pH to 3.5, add tallow propylene diamine and sodium chloride, and stir evenly to prepare a soap solution. Heat the modified asphalt prepared above to melting and slowly add it to the prepared soap solution, and keep mixing and grinding and emulsifying at 85 °C to obtain modified emulsified asphalt. Among them, the content of modified asphalt is 73 wt%, the content of emulsifier is 3.5 wt%, the content of stabilizer is 0.3 wt%, and the content of water is 23.2 wt%.

[0089] Comparative Example 2

[0090] Heat 300 g of petroleum asphalt with a softening point of 52.2 °C to a molten state, add 27.8 g of the modifier II prepared above, and stir using mechanical stirring at a rotation speed of 1800 rpm. Stir and react at 120 °C for 6 h to obtain cationic matrix asphalt.

[0091] Add 18.8 g of SBS and 24.2 g of extracted oil to the two feeding ports of the extruder respectively, extrude into strips at 180 °C, and cut into small particles with an average particle size of 3.5 mm after cooling.

[0092] Add the small particles prepared above to the prepared cationic matrix asphalt, stir at 180 °C for 0.5 h, add 0.15% of elemental sulfur and 0.15% of tetramethylthiuram monosulfide, and stir for 4 h to obtain modified asphalt.

[0093] Heat 85 mL of water to 85 °C. Add hydrochloric acid with a mass concentration of 10 wt% to the hot water, adjust the pH to 3.5, add tallow propylene diamine and sodium chloride, and stir evenly to prepare a soap solution. Heat the modified asphalt to melting and slowly add it to the prepared soap solution, and keep mixing and grinding and emulsifying at 85 °C to obtain modified emulsified asphalt. Among them, the content of modified asphalt is 73 wt%, the content of emulsifier is 3.5 wt%, the content of stabilizer is 0.3 wt%, and the content of water is 23.2 wt%.

[0094] Test Example:

[0095] Preparation of modified emulsified asphalt mixture: According to the AC-10 aggregate gradation, add 10% of the modified emulsified asphalt prepared in Examples 3-6 and Comparative Examples 1-2 above. Add 1% of cement and mix dry with the aggregate for 60 s before mixing the emulsified asphalt mixture, add the modified emulsified asphalt, and stir for 90 s to complete the mixing of the mixture. Marshall specimens are formed by compaction 50 times on each side, and accelerated curing is carried out in an environmental chamber at 105 °C for 24 h without demolding, and then the Marshall specimens are taken out. After the specimens are cooled, compact 25 times on each side again to complete the preparation of the specimens.

[0096] The properties of the modified asphalt and the properties of the modified emulsified asphalt mixture obtained in the above examples and comparative examples are shown in Table 1 and Table 2 respectively. It can be seen from the data in Table 1 that after the asphalt is modified with the modifier, the softening point is increased and it has a positive charge. The data in Table 2 show that the performance of the mixture of the modified emulsified asphalt prepared by the present invention is enhanced.

[0097] Table 1 Properties of the modified asphalt in the examples and comparative examples

[0098] Property Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 Softening point / °C 86.4 88.2 91.5 90.6 80.5 82.8 Viscous toughness / N·m 25.5 27.2 31.3 30.6 20.2 23.9 Zeta potential / mV +27.6 +28.5 +29.4 +30.6 - +14.8

[0099] Table 2 Properties of the modified emulsified asphalt mixture in the examples and comparative examples

[0100]

[0101] *Note: Emulsification failed in Comparative Example 1.

Claims

1. A modified emulsified asphalt, characterized in that: by weight, it comprises the following components: The modified asphalt, by weight, comprises the following components: The cationized base asphalt is obtained by a chemical grafting reaction of a modifier and an activated base asphalt.

2. The modified emulsified asphalt according to claim 1, characterized in that: The preparation method of the modifier includes: first, a nitrile monomer is obtained under the action of a catalyst to form a cyclic monomer; then the above cyclic monomer is subjected to ring-opening polymerization to form a polymer of the cyclic monomer; finally, the polymer of the cyclic monomer is hydrolyzed under acidic conditions to obtain the modifier.

3. The modified emulsified asphalt according to claim 1 or 2, characterized in that: The preparation method of the modifier includes: (a) Add a nitrile monomer and a catalyst to a reactor, heat to 90 - 120 °C, then add an amino alcohol monomer, and react for 30 - 60 h to obtain a cyclic monomer; (b) Mix the cyclic monomer obtained in step (a), an initiator, and a nitrile monomer, react at 100 - 160 °C for 30 - 90 min, then add a methanol solution of KOH at -10 °C - 10 °C, stir for 8 - 24 h, remove the solvent, dissolve the residual polymer in chloroform, precipitate and purify, and dry to obtain a polymer of the cyclic monomer; (c) Dissolve the polymer of the cyclic monomer obtained in step (b) in hot water, heat under reflux, add a hydrochloric acid solution, react for 24 - 72 h, remove the solvent, redissolve the residual polymer in hot water, add a NaOH solution until the pH value of the solution is 9 - 10, precipitate by centrifugation, remove the supernatant, repeat 2 - 3 times, and dry to obtain the modifier.

4. The modified emulsified asphalt according to claim 3, characterized in that: In step (a), the nitrile monomer is ultra-dry acetonitrile and / or propionitrile; the catalyst is zinc acetate dihydrate; wherein, the volume-mass ratio of the nitrile monomer to the catalyst added is 10 - 20∶1 mL / g; the amino alcohol monomer is one or more of 2-aminoethanol and 3-amino-1-propanol; the volume ratio of the nitrile monomer to the amino alcohol monomer added is 1∶1 - 3.

5. The modified emulsified asphalt according to claim 3, characterized in that: In step (b), the initiator is a sulfonate cationic initiator, preferably one or more of methyl p-toluenesulfonate, ethyl trifluoromethanesulfonate, 3-butynyl p-toluenesulfonate, etc.; in step (b), the nitrile monomer is ultra-dry acetonitrile and / or propionitrile; in step (b), the volume ratio of the initiator to the cyclic monomer added is 0.01 - 0.1∶1; the volume ratio of the cyclic monomer to the nitrile monomer is 1∶1 - 3.

6. The modified emulsified asphalt according to claim 3, characterized in that: In step (b), the concentration of KOH in the methanol solution of KOH is 0.8 - 1.2 mol / L; the amount of the methanol solution of KOH added is 1 / 10 - 1 / 40 of the volume of the cyclic monomer.

7. The modified emulsified asphalt according to claim 3, characterized in that: In step (c), the temperature of the hot water is 40 - 80°C; the temperature of the heating reflux is 80 - 120°C, and the heating reflux time is 10 - 30 min; the mass concentration of the hydrochloric acid solution is 30% - 38%; the mass ratio of the addition amount of the hydrochloric acid solution to the addition amount of the polymer of the cyclic monomer is 1 - 20∶1; the drying conditions are: vacuum drying at 50 - 70°C for 24 - 72 h.

8. The modified emulsified asphalt according to claim 1, characterized in that: the activated matrix asphalt is prepared by reacting matrix asphalt with organic acid anhydride; the matrix asphalt is selected from one or more of petroleum asphalt and natural asphalt; the softening point of the matrix asphalt is 30°C - 70°C; the organic acid anhydride is a mono- or poly-organic acid anhydride, preferably selected from one or more of maleic anhydride, polyethylene glycol anhydride, polyglutaric anhydride, polynonanoic anhydride, and polyisobutylene succinic anhydride.

9. The modified emulsified asphalt according to claim 1, characterized in that: the high molecular polymer is SBS and / or SIS; and / or, the plasticizer is one or more of extracted oil, naphthenic oil, and bio-oil; and / or, the crosslinking agent is a sulfur-containing organic and / or inorganic substance, preferably one or more of elemental sulfur and thiuram compounds; the thiuram compounds are one or more of tetramethylthiuram monosulfide and tetramethylthiuram disulfide; and / or, the emulsifier is a long-chain fatty amine cationic emulsifier, preferably one or more of tallow propylene diamine, octadecyl dipropylene triamine, octadecyl propylene triamine, etc.; and / or, the stabilizer is one or more of calcium chloride, sodium chloride, and ammonium chloride.

10. A method for preparing the modified emulsified asphalt according to any one of claims 1 - 9, characterized in that: comprising: (I) Preparing modified asphalt; (II) Mixing an emulsifier, a stabilizer with water, and adjusting the pH value to obtain a soap solution; (III) Mixing and emulsifying the modified asphalt prepared in step (I) with the soap solution obtained in step (II) to obtain the modified emulsified asphalt.

11. The preparation method according to claim 10, characterized in that: the method for preparing the modified asphalt in step (I) comprises: (1) Preparing a modifier; (2) Preparing activated matrix asphalt; (3) Heating and melting the activated matrix asphalt, mixing it with the modifier, reacting under stirring, and adding a halogenated hydrocarbon to continue the reaction after the reaction is completed to obtain a cationized matrix asphalt; (4) Mixing the high molecular polymer with the plasticizer and extruding and molding; (5) Mixing the material molded in step (4) with the cationized matrix asphalt, and adding a crosslinking agent, and stirring to obtain the modified asphalt.

12. The preparation method according to claim 11, characterized in that: in step (2), the method for preparing the activated matrix asphalt comprises: heating the base asphalt to a molten state, adding 2% - 20% by weight of the organic acid anhydride based on the base asphalt, and introducing an inert gas to keep the pressure in the asphalt reaction kettle at 0.2 - 2.0 MPa, the reaction temperature is 150 - 250°C, and the reaction time is 2 - 8 hours to obtain the activated matrix asphalt.

13. The preparation method according to claim 11, characterized in that: in step (3), the activated matrix asphalt is heated and melted, mixed with the modifier, and reacted under stirring, and the rotation speed of the stirring is 80-2000 rpm; the conditions for the reaction are: the reaction temperature is 50-120 °C, and the reaction time is 2-10 h.

14. The preparation method according to claim 11, characterized in that: in step (3), the addition amount of the modifier is 0.5%-10% of the mass of the activated matrix asphalt.

15. The preparation method according to claim 11, characterized in that: in step (3), the halogenated hydrocarbon is benzyl chloride and / or cetyl bromide; and / or, the mass ratio of the modifier to the halogenated hydrocarbon is 1-3:1; and / or, in step (3), the conditions for continuing the reaction after adding the halogenated hydrocarbon are: reacting at 80-140 °C for 1-4 h, preferably reacting at 100-120 °C for 2-3 h.

16. The preparation method according to claim 11, characterized in that: in step (5), after adding the crosslinking agent, the stirring conditions are: stirring at 140-180 °C for 1-5 h to obtain the modified asphalt.

17. The preparation method according to claim 10, characterized in that: in step (II), when preparing the soap solution, the system temperature is controlled at 70-90 °C; the pH value is adjusted to 2-4.

18. The preparation method according to claim 10, characterized in that: in step (III), the modified asphalt prepared in step (I) is first heated and melted, and then mixed and emulsified with the soap solution obtained in step (II), and the emulsification temperature is: 70-90 °C.

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