Preparation method of high-stability modified emulsified asphalt

Abstract

The invention discloses a preparation method of high-stability modified emulsified asphalt, and particularly relates to the technical field of asphalt materials, which comprises the following steps (by weight): S01, mixing 30-50 parts by weight of styrene-butadiene latex with the solid content of 45-60%, 10-25 parts by weight of acrylate copolymer emulsion with the glass transition temperature of-20-10 DEG C and 0.5-8 parts by weight of silane coupling agent to obtain a mixture A; a mixed emulsion is obtained; s02, adding 8-15 parts by weight of matrix asphalt, 2-8 parts by weight of a maleic anhydride grafted polypropylene compatilizer with the grafting rate of 1.0%-2.5% and a stabilizer into the mixed emulsion, and performing high-speed shearing at the rotating speed of 3000-5000 rpm for 20-40 min to obtain the modified polymer emulsion. According to the invention, the storage stability, the thermal stability and the interface bonding strength are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of asphalt materials, and particularly to a preparation method of highly stable modified emulsified asphalt. Background Art

[0002] Emulsified asphalt is a stable colloidal material formed by asphalt, water, emulsifier and other additives through high-speed shearing, and is widely used in fields such as road penetration layer, tack coat, seal coat and cold mix asphalt mixture. Compared with traditional hot asphalt, emulsified asphalt has advantages such as energy conservation, environmental protection and convenient construction, but its stability problem has always been a technical bottleneck restricting its large-scale application.

[0003] At present, ordinary emulsified asphalt is prone to stratification and demulsification during storage and transportation, resulting in the coalescence and precipitation of asphalt particles, especially under high temperature or long-term static conditions. To improve stability, existing technologies mostly adopt methods such as adding modifiers (such as SBS, SBR, latex, etc.) or optimizing the emulsification process (such as adjusting the pH value, shear rate). For example, a modified emulsified asphalt based on cationic emulsifier disclosed in Chinese Patent with publication number CN116178975A improves the adhesion by adding polymer latex, but its storage stability is still limited by the compatibility between the modifier and asphalt, and phase separation is prone to occur under high temperature conditions. Summary of the Invention

[0004] The purpose of the present invention is to provide a preparation method of highly stable modified emulsified asphalt to solve the above problems.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] A preparation method of highly stable modified emulsified asphalt, comprising the following steps (by weight):

[0007] S01. Mix 30 - 50 parts by weight of styrene-butadiene latex with a solid content of 45% - 60%, 10 - 25 parts by weight of acrylate copolymer emulsion with a glass transition temperature of -20 - 10°C and 0.5 - 8 parts by weight of silane coupling agent to obtain a mixed emulsion;

[0008] S02. Add 8 - 15 parts by weight of matrix asphalt, 2 - 8 parts by weight of maleic anhydride grafted polypropylene compatibilizer with a grafting rate of 1.0% - 2.5% and a stabilizer to the mixed emulsion, and perform high-speed shearing at a speed of 3000 - 5000 rpm for 20 - 40 min to obtain a modified polymer emulsion;

[0009] S03. Mix 12 - 18 parts by weight of the modified polymer emulsion, 100 parts by weight of matrix asphalt, 0.1 - 0.8 parts by weight of isocyanate crosslinking agent, and 0.05 - 0.3 parts by weight of hindered phenol antioxidant, shear at 160 - 175 °C at 800 - 1200 rpm for 40 - 60 min, and add the antioxidant 10 - 20 min before the end of shearing. Then cool down to 90 - 110 °C, add 0.2 - 1.5 parts by weight of a composite emulsifier prepared by compounding sodium dodecylbenzenesulfonate and fatty alcohol polyoxyethylene ether at a mass ratio of 1:0.5 - 1:2, and stir until the absolute value of Zeta potential ≤ 28 mV to obtain highly stable modified asphalt;

[0010] S04. Mix 100 parts by weight of water, 3 - 6 parts by weight of cationic emulsifier, and 0.5 - 3 parts by weight of pH regulator to obtain an alkaline soap solution with a pH between 10 and 12;

[0011] S05. Preheat 55 - 65 parts by weight of the highly stable modified asphalt to 85 - 95 °C, and then circulate and grind it with 35 - 45 parts by weight of the soap solution through a colloid mill at 4000 - 6000 rpm for 3 - 5 times to prepare modified emulsified asphalt.

[0012] Preferably, the stabilizer is 0.5 - 3 parts by weight of nano - silica with a particle size of 20 - 50 nm or 0.5 - 3 parts by weight of montmorillonite stabilizer with an interlayer spacing of 1 - 3 nm.

[0013] Preferably, the montmorillonite in the montmorillonite stabilizer is sodium - based montmorillonite with a cation exchange capacity ≥ 80 mmol / 100 g.

[0014] Preferably, the D90 particle size growth of the modified emulsified asphalt ≤ 12%, and the change rate of rotational viscosity at 25 °C ≤ 15%.

[0015] Preferably, the silane coupling agent is γ - aminopropyltriethoxysilane (KH550) or γ - (2,3 - epoxypropoxy) propyltrimethoxysilane (KH560), and its dosage is 1.5 - 5 parts by weight.

[0016] Preferably, the crosslinking agent is toluene diisocyanate (TDI) or hexamethylene diisocyanate (HDI), and the molar ratio of the crosslinking agent to the styrene unit in the styrene - butadiene latex is 1:(20 - 50).

[0017] Preferably, the HLB value of the composite emulsifier is 10 - 14.

[0018] Preferably, the mass ratio of sodium dodecylbenzenesulfonate to fatty alcohol polyoxyethylene ether is (1:1 - 1.8).

[0019] Preferably, the cationic emulsifier is cetyltrimethylammonium bromide (CTAB) or octadecyltrimethylammonium chloride (OTAC).

[0020] Preferably, in step S03, the shear rate is 1000 - 1200 rpm, the shear time is 50 - 60 min, and the antioxidant is pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (Irganox 1010), and its addition time is 15 - 20 min before the end of shearing.

[0021] In the above technical solution, a preparation method of a highly stable modified emulsified asphalt provided by the present invention has the following beneficial effects:

[0022] 1. Through the introduction of nano-silica or montmorillonite stabilizers and the precise regulation of the composite emulsifier system, the modified emulsified asphalt prepared by the present invention shows extremely high stability during storage. Experimental data shows that the particle size growth is controlled within 12%, and the change rate of rotational viscosity at 25°C does not exceed 15%, ensuring that the product can still maintain good use performance after long-term storage, and greatly reducing the risk of performance attenuation caused by improper storage.

[0023] 2. The synergistic effect of cyanate ester crosslinkers and hindered phenol antioxidants constructs a dense chemical crosslinking network and effectively neutralizes free radicals, significantly improving the high-temperature stability and anti-aging ability of asphalt.

[0024] 3. The silane coupling agent forms a strong chemical bond between the inorganic filler and the organic polymer, while the maleic anhydride grafted polypropylene compatibilizer promotes the compatibility between the polymer and the asphalt. As a result, the interfacial bonding strength of the modified emulsified asphalt is significantly improved, the peel strength is increased, and the elasticity and cohesion are optimized, effectively resisting the deformation and damage of the road surface caused by traffic loads.

[0025] 4. Through the optimization of the colloid mill high-shear process and the composite emulsifier system, the modified emulsified asphalt prepared by the present invention has excellent construction workability. The absolute value of its Zeta potential is controlled within 28 mV, ensuring the stability of the emulsion during construction processes such as pumping and spraying, and reducing the construction difficulty and energy consumption. Specific Embodiments

[0026] Next, the technical solutions in the embodiments of the present invention will be described clearly and completely in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0027] Example 1

[0028] A preparation method of high - stability modified emulsified asphalt includes the following steps (by weight):

[0029] S01. Mix 30 - 50 parts by weight of styrene - butadiene latex with a solid content of 45% - 60%, 10 - 25 parts by weight of acrylate copolymer emulsion with a glass transition temperature of - 20 - 10°C, and 0.5 - 8 parts by weight of silane coupling agent to obtain a mixed emulsion;

[0030] S02. Add 8 - 15 parts by weight of matrix asphalt, 2 - 8 parts by weight of maleic anhydride - grafted polypropylene compatibilizer with a grafting rate of 1.0% - 2.5%, and a stabilizer to the mixed emulsion, and perform high - speed shearing at a speed of 3000 - 5000 rpm for 20 - 40 min to obtain a modified polymer emulsion;

[0031] S03. Mix 12 - 18 parts by weight of the modified polymer emulsion, 100 parts by weight of matrix asphalt, 0.1 - 0.8 parts by weight of isocyanate cross - linker, and 0.05 - 0.3 parts by weight of hindered phenol antioxidant (the shear rate is 1000 - 1200 rpm, the shear time is 50 - 60 min, and the hindered phenol antioxidant is added 15 - 20 min before the end of shearing). After the above is completed, shear at 160 - 175°C at 800 - 1200 rpm for 40 - 60 min, and add the antioxidant 10 - 20 min before the end of shearing. Then cool down to 90 - 110°C, add 0.2 - 1.5 parts by weight of a composite emulsifier prepared by compounding sodium dodecyl benzene sulfonate and fatty alcohol polyoxyethylene ether in a mass ratio of 1:0.5 - 1:2, and stir until the absolute value of the Zeta potential ≤ 28 mV to obtain high - stability modified asphalt;

[0032] S04. Mix 100 parts by weight of water, 3 - 6 parts by weight of cationic emulsifier, and 0.5 - 3 parts by weight of pH regulator to obtain an alkaline soap solution with a pH between 10 and 12;

[0033] S05. Preheat 55 - 65 parts by weight of high - stability modified asphalt to 85 - 95°C, and then circulate and grind it with 35 - 45 parts by weight of soap solution through a colloid mill at 4000 - 6000 rpm for 3 - 5 times to obtain modified emulsified asphalt.

[0034] The above stabilizer is 0.5 - 3 parts by weight of nano - silica with a particle size of 20 - 50 nm or 0.5 - 3 parts by weight of montmorillonite stabilizer with an interlayer spacing of 1 - 3 nm.

[0035] Further, the montmorillonite in the montmorillonite stabilizer in the above example is sodium - based montmorillonite, and the cation exchange capacity ≥ 80 mmol / 100 g.

[0036] Secondly, the D90 particle size growth of the modified emulsified asphalt is ≤12%, and the change rate of rotational viscosity at 25°C is ≤15%.

[0037] Furthermore, the above silane coupling agent is γ-aminopropyltriethoxysilane (KH550) or γ-(2,3-epoxypropoxy)propyltrimethoxysilane (KH560), and its dosage is 1.5 - 5 parts by weight.

[0038] Even further, the crosslinking agent is toluene diisocyanate (TDI) or hexamethylene diisocyanate (HDI), and the molar ratio of the crosslinking agent to the styrene unit in the styrene-butadiene latex is 1:(20 - 50).

[0039] The HLB value of the composite emulsifier is 10 - 14.

[0040] The mass ratio of sodium dodecylbenzenesulfonate to fatty alcohol polyoxyethylene ether is 1:(1 - 1.8).

[0041] The cationic emulsifier in the above examples is cetyltrimethylammonium bromide (CTAB) or octadecyltrimethylammonium chloride (OTAC).

[0042] The antioxidant in the above examples is pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (Irganox 1010), and its addition time is 15 - 20 min before the end of shearing.

[0043] Example Two

[0044] Based on the above Example One, its preparation method includes the following steps (in weight):

[0045] S01. Mix 30 parts by weight of styrene-butadiene latex with a solid content of 60%, 10 parts by weight of acrylate copolymer emulsion with a glass transition temperature of -20 - 10°C, and 0.5 part by weight of silane coupling agent to obtain a mixed emulsion;

[0046] S02. Add 8 parts by weight of matrix asphalt, 2 parts by weight of maleic anhydride grafted polypropylene compatibilizer with a grafting rate of 1.0%, and a stabilizer to the mixed emulsion, and perform high-speed shearing at a speed of 3000 - 5000 rpm for 20 - 40 min to obtain a modified polymer emulsion;

[0047] S03. Mix 12 parts by weight of the modified polymer emulsion, 100 parts by weight of the base asphalt, 0.1 part by weight of the isocyanate cross-linking agent, and 0.05 part by weight of the hindered phenol antioxidant (shear rate: 1000 - 1200 rpm, shear time: 50 - 60 min, add the hindered phenol antioxidant 15 - 20 min before the end of shearing). After the above is completed, shear at 160 - 175 °C at 800 - 1200 rpm for 40 - 60 min, and add the antioxidant 10 - 20 min before the end of shearing. Subsequently, cool down to 90 - 110 °C, add 0.2 part by weight of the composite emulsifier prepared by compounding sodium dodecylbenzenesulfonate and fatty alcohol polyoxyethylene ether at a mass ratio of 1:0.5, and stir until the absolute value of the Zeta potential ≤ 28 mV to obtain the highly stable modified asphalt;

[0048] S04. Mix 100 parts by weight of water, 3 parts by weight of the cationic emulsifier, and 0.5 part by weight of the pH regulator to obtain an alkaline soap solution with a pH between 10;

[0049] S05. Preheat 55 parts by weight of the highly stable modified asphalt to 85 - 95 °C, and then circulate and grind it with 35 parts by weight of the soap solution through a colloid mill at 4000 - 6000 rpm for 3 - 5 times to prepare the modified emulsified asphalt.

[0050] The above stabilizer is 0.5 part by weight of nano-silica with a particle size of 20 or 0.5 part by weight of montmorillonite stabilizer with an interlayer spacing of 1.

[0051] Further, the montmorillonite in the montmorillonite stabilizer in the above examples is sodium-based montmorillonite, and the cation exchange capacity ≥ 80 mmol / 100 g.

[0052] Secondly, the D90 particle size growth of the modified emulsified asphalt ≤ 12%, and the change rate of the rotational viscosity at 25 °C ≤ 15%.

[0053] Furthermore, the above silane coupling agent is γ-aminopropyltriethoxysilane (KH550) or γ-(2,3-epoxypropoxy)propyltrimethoxysilane (KH560), and its dosage is 1.5 parts by weight.

[0054] Even further, the cross-linking agent is toluene diisocyanate (TDI) or hexamethylene diisocyanate (HDI), and the molar ratio of the cross-linking agent to the styrene unit in the styrene-butadiene latex is 1:20.

[0055] The HLB value of the composite emulsifier is 10.

[0056] The mass ratio of sodium dodecylbenzenesulfonate to fatty alcohol polyoxyethylene ether is 1:1.

[0057] The cationic emulsifiers in the above embodiments are cetyltrimethylammonium bromide (CTAB) or octadecyltrimethylammonium chloride (OTAC).

[0058] The antioxidant in the above embodiments is pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (Irganox 1010), and its addition time is 15 - 20 min before the end of shearing.

[0059] Example 3

[0060] Based on the above Example 1, its preparation method includes the following steps (in terms of weight):

[0061] S01. Mix 50 parts by weight of styrene-butadiene latex with a solid content of 45%, 25 parts by weight of acrylate copolymer emulsion with a glass transition temperature of -20 to 10 °C, and 8 parts by weight of silane coupling agent to obtain a mixed emulsion;

[0062] S02. Add 15 parts by weight of matrix asphalt, 8 parts by weight of maleic anhydride-grafted polypropylene compatibilizer with a grafting rate of 1.0% - 2.5%, and a stabilizer to the mixed emulsion, and perform high-speed shearing at a speed of 3000 - 5000 rpm for 20 - 40 min to obtain a modified polymer emulsion;

[0063] S03. Mix 18 parts by weight of the modified polymer emulsion, 100 parts by weight of matrix asphalt, 0.8 parts by weight of isocyanate cross-linking agent, and 0.3 parts by weight of hindered phenol antioxidant (the shearing rate is 1000 - 1200 rpm, the shearing time is 50 - 60 min, and the hindered phenol antioxidant is added 15 - 20 min before the end of shearing). After the above is completed, shear at 160 - 175 °C at 800 - 1200 rpm for 40 - 60 min, and add the antioxidant 10 - 20 min before the end of shearing. Then cool down to 90 - 110 °C, add 0.2 - 1.5 parts by weight of a composite emulsifier prepared by compounding sodium dodecylbenzenesulfonate and fatty alcohol polyoxyethylene ether in a mass ratio of 1:2, and stir until the absolute value of the Zeta potential ≤ 28 mV to obtain a highly stable modified asphalt;

[0064] S04. Mix 100 parts by weight of water, 6 parts by weight of cationic emulsifier, and 3 parts by weight of pH regulator to obtain an alkaline soap solution with a pH of 12;

[0065] S05. Preheat 65 parts by weight of the highly stable modified asphalt to 85 - 95 °C, and then circulate and grind it with 45 parts by weight of the soap solution through a colloid mill at 4000 - 6000 rpm for 3 - 5 times to obtain a modified emulsified asphalt.

[0066] The above stabilizer is nano-silica with 3 parts by weight and a particle size of 20 - 50 nm, or montmorillonite stabilizer with 3 parts by weight and an interlayer spacing of 3 nm.

[0067] Furthermore, the montmorillonite in the montmorillonite stabilizer in the above example is sodium-based montmorillonite, and the cation exchange capacity ≥ 80 mmol / 100 g.

[0068] Secondly, the D90 particle size growth of the modified emulsified asphalt ≤ 12%, and the change rate of rotational viscosity at 25°C ≤ 15%.

[0069] Furthermore, the above silane coupling agent is γ-aminopropyltriethoxysilane (KH550) or γ-(2,3-epoxypropoxy)propyltrimethoxysilane (KH560), and its dosage is 5 parts by weight.

[0070] Even further, the crosslinking agent is toluene diisocyanate (TDI) or hexamethylene diisocyanate (HDI), and the molar ratio of the crosslinking agent to the styrene unit in the styrene-butadiene latex is 1:50.

[0071] The HLB value of the composite emulsifier is 14.

[0072] The mass ratio of sodium dodecylbenzenesulfonate to fatty alcohol polyoxyethylene ether is 1:1.8.

[0073] The cationic emulsifier in the above example is cetyltrimethylammonium bromide (CTAB) or octadecyltrimethylammonium chloride (OTAC).

[0074] The antioxidant in the above example is pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (Irganox 1010), and its addition time is 15 - 20 min before the end of shearing.

[0075] Example 4

[0076] Based on the above Example 1, its preparation method includes the following steps (in units of weight):

[0077] S01. Mix 40 parts by weight of styrene-butadiene latex with a solid content of 45%, 18 parts by weight of acrylate copolymer emulsion with a glass transition temperature of -20 - 10°C, and 5 parts by weight of silane coupling agent to obtain a mixed emulsion;

[0078] S02. Add 12 parts by weight of matrix asphalt, 5 parts by weight of maleic anhydride grafted polypropylene compatibilizer with a grafting rate of 1.0% - 2.5%, and a stabilizer to the mixed emulsion, and perform high-speed shearing at a speed of 3000 - 5000 rpm for 20 - 40 min to obtain a modified polymer emulsion;

[0079] S03. Mix 15 parts by weight of the modified polymer emulsion, 100 parts by weight of the matrix asphalt, 0.5 part by weight of the isocyanate crosslinking agent, and 0.1 part by weight of the hindered phenol antioxidant (the shear rate is 1000 - 1200 rpm, the shear time is 50 - 60 min, and the hindered phenol antioxidant is added 15 - 20 min before the end of shearing). After the above is completed, shear at 160 - 175°C at 800 - 1200 rpm for 40 - 60 min, and add the antioxidant 10 - 20 min before the end of shearing. Then cool down to 90 - 110°C, add 0.8 part by weight of the composite emulsifier prepared by compounding sodium dodecylbenzenesulfonate and fatty alcohol polyoxyethylene ether according to the mass ratio of 1:1.32, and stir until the absolute value of the Zeta potential ≤ 28 mV to obtain the highly stable modified asphalt;

[0080] S04. Mix 100 parts by weight of water, 5 parts by weight of the cationic emulsifier, and 1.5 parts by weight of the pH regulator to obtain an alkaline soap solution with a pH between 11;

[0081] S05. After preheating 60 parts by weight of the highly stable modified asphalt to 85 - 95°C, circulate and grind it with 40 parts by weight of the soap solution through a colloid mill at 4000 - 6000 rpm for 3 - 5 times to prepare the modified emulsified asphalt.

[0082] The above stabilizer is 1.5 parts by weight of nano - silica with a particle size of 20 - 50 nm or 0.5 - 3 parts by weight of montmorillonite stabilizer with an interlayer spacing of 1 - 3 nm.

[0083] Further, the montmorillonite in the montmorillonite stabilizer in the above examples is sodium - based montmorillonite, and the cation exchange capacity ≥ 80 mmol / 100 g.

[0084] Secondly, the D90 particle size growth of the modified emulsified asphalt ≤ 12%, and the change rate of the rotational viscosity at 25°C ≤ 15%.

[0085] Furthermore, the above silane coupling agent is γ - aminopropyltriethoxysilane (KH550) or γ - (2,3 - epoxypropoxy) propyltrimethoxysilane (KH560), and its dosage is 3.5 parts by weight.

[0086] Even further, the crosslinking agent is toluene diisocyanate (TDI) or hexamethylene diisocyanate (HDI), and the molar ratio of the crosslinking agent to the styrene unit in the styrene - butadiene latex is 1:30.

[0087] The HLB value of the composite emulsifier is 10 - 14.

[0088] The mass ratio of sodium dodecylbenzenesulfonate to fatty alcohol polyoxyethylene ether is 1:1.

[0089] The cationic emulsifiers in the above embodiments are cetyltrimethylammonium bromide (CTAB) or octadecyltrimethylammonium chloride (OTAC).

[0090] The antioxidant in the above embodiments is pentaerythritol tetrakis [β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (Irganox 1010), and its addition time is 15 - 20 min before the end of shearing.

[0091] Example Five

[0092] Based on the above Example One, its preparation method includes the following steps (in terms of weight):

[0093] S01. Mix 55 parts by weight of styrene-butadiene latex with a solid content of 45%, 30 parts by weight of acrylate copolymer emulsion with a glass transition temperature of -20 to 10°C, and 9 parts by weight of silane coupling agent to obtain a mixed emulsion;

[0094] S02. Add 16 parts by weight of matrix asphalt, 9 parts by weight of maleic anhydride-grafted polypropylene compatibilizer with a grafting rate of 1.0% - 2.5%, and a stabilizer to the mixed emulsion, and perform high-speed shearing at 3000 - 5000 rpm for 20 - 40 min to obtain a modified polymer emulsion;

[0095] S03. Mix 20 parts by weight of the modified polymer emulsion, 100 parts by weight of matrix asphalt, 0.9 parts by weight of isocyanate cross-linking agent, and 0.4 parts by weight of hindered phenol antioxidant (the shearing rate is 1000 - 1200 rpm, the shearing time is 50 - 60 min, and the hindered phenol antioxidant is added 15 - 20 min before the end of shearing). After the above is completed, shear at 160 - 175°C at 800 - 1200 rpm for 40 - 60 min, and add the antioxidant 10 - 20 min before the end of shearing. Then cool down to 90 - 110°C, add 0.2 - 1.5 parts by weight of a composite emulsifier prepared by compounding sodium dodecylbenzenesulfonate and fatty alcohol polyoxyethylene ether at a mass ratio of 1:1.3, and stir until the absolute value of the Zeta potential ≤ 28 mV to obtain a highly stable modified asphalt;

[0096] S04. Mix 100 parts by weight of water, 7 parts by weight of cationic emulsifier, and 3.5 parts by weight of pH regulator to obtain an alkaline soap solution with a pH between 10;

[0097] S05. Preheat 55 - 65 parts by weight of the highly stable modified asphalt to 85 - 95°C, and then circulate and grind it with 50 parts by weight of the soap solution through a colloid mill at 4000 - 6000 rpm for 3 - 5 times to obtain a modified emulsified asphalt.

[0098] The above stabilizer is nano-silica with a content of 4 parts by weight and a particle size of 20 - 50 nm, or montmorillonite stabilizer with a content of 4 parts by weight and an interlayer spacing of 1 - 3 nm.

[0099] Furthermore, the montmorillonite in the montmorillonite stabilizer in the above examples is sodium-based montmorillonite, and the cation exchange capacity ≥ 80 mmol / 100 g.

[0100] Secondly, the D90 particle size growth of the modified emulsified asphalt ≤ 12%, and the change rate of rotational viscosity at 25°C ≤ 15%.

[0101] Moreover, the above silane coupling agent is γ-aminopropyltriethoxysilane (KH550) or γ-(2,3-epoxypropoxy)propyltrimethoxysilane (KH560), and its dosage is 6 parts by weight.

[0102] Even further, the crosslinking agent is toluene diisocyanate (TDI) or hexamethylene diisocyanate (HDI), and the molar ratio of the crosslinking agent to the styrene unit in the styrene-butadiene latex is 1:60.

[0103] The HLB value of the composite emulsifier is 1.

[0104] The mass ratio of sodium dodecylbenzenesulfonate to fatty alcohol polyoxyethylene ether is 1:1.9.

[0105] The cationic emulsifier in the above examples is cetyltrimethylammonium bromide (CTAB) or octadecyltrimethylammonium chloride (OTAC).

[0106] The antioxidant in the above examples is pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (Irganox 1010), and its addition time is 15 - 20 min before the end of shearing.

[0107] Experimental test results:

[0108] Take the modified emulsified asphalt prepared in Example 2, Example 3, Example 4, and Example 5 and store it at 60°C, and observe the changes within 7 days to obtain the changes of the modified emulsified asphalt (see

[0109] Table 1):

[0110]

[0111] Table 1

[0112] Take the modified emulsified asphalt prepared in Example 2, Example 3, and Example 4 and store it at 180°C, and observe the changes within four hours to obtain the changes of the modified emulsified asphalt (see Table 2):

[0113]

[0114]

[0115] Table 2

[0116] In summary, as shown in Table 1, for the modified asphalt materials prepared, by observing the delamination and flocculation results of the materials at 7 points at 60°C, it can be seen that in the provided preparation method, the better the effect is when the material weight fraction is higher. And after reaching the maximum range provided in the first embodiment, there is no obvious change when continuing to increase. Similarly, as shown in Table 1, for the modified asphalt materials prepared, by observing the delamination and flocculation results of the materials at 7 points at 60°C, it can be seen that in the provided preparation method, the better the effect is when the material weight fraction is higher. And after reaching the maximum range provided in the first embodiment, there is no obvious change when continuing to increase. Also, the higher the content of styrene-butadiene latex in every 50 parts by weight, the better the effect.

[0117] In summary, through the introduction of nano-silica or montmorillonite stabilizers and the precise regulation of the composite emulsifier system, the modified emulsified asphalt prepared by the present invention exhibits extremely high stability during storage. Experimental data shows that the growth of its particle size is controlled within 12%, and the change rate of rotational viscosity at 25°C does not exceed 15%, ensuring that the product can still maintain good use performance after long-term storage, and greatly reducing the risk of performance attenuation caused by improper storage. Secondly, the synergistic effect of cyanate crosslinkers and hindered phenol antioxidants constructs a dense chemical crosslinking network and effectively neutralizes free radicals, significantly improving the high-temperature stability and anti-aging ability of the asphalt. Furthermore, the silane coupling agent forms a strong chemical bonding between the inorganic filler and the organic polymer, while the maleic anhydride grafted polypropylene compatibilizer promotes the compatibility between the polymer and the asphalt. As a result, the interfacial bonding strength of the modified emulsified asphalt is significantly improved, the peel strength is increased by 25%, and at the same time, the elasticity and cohesion are optimized, effectively resisting the deformation and damage of the road surface caused by traffic loads. Finally, through the optimization of the colloid mill high-shear process and the composite emulsifier system, the modified emulsified asphalt prepared by the present invention has excellent construction workability. The absolute value of its Zeta potential is controlled within 28 mV, ensuring the stability of the emulsion during construction processes such as pumping and spraying, and reducing the construction difficulty and energy consumption.

[0118] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-mentioned exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, in any regard, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, it is intended to include all changes falling within the meaning and scope of the equivalent elements of the claims in the present invention.

[0119] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A preparation method of a highly stable modified emulsified asphalt, characterized in that, Including the following steps (by weight): S01. Mix 30 - 50 parts by weight of styrene-butadiene latex with a solid content of 45% - 60%, 10 - 25 parts by weight of acrylate copolymer emulsion with a glass transition temperature of -20 - 10°C, and 0.5 - 8 parts by weight of silane coupling agent to obtain a mixed emulsion; S02. Add 8 - 15 parts by weight of matrix asphalt, 2 - 8 parts by weight of maleic anhydride grafted polypropylene compatibilizer with a grafting rate of 1.0% - 2.5%, and a stabilizer to the above mixed emulsion, and perform high-speed shearing at 3000 - 5000 rpm for 20 - 40 min to obtain a modified polymer emulsion; S03. Mix 12 - 18 parts by weight of the above modified polymer emulsion, 100 parts by weight of matrix asphalt, 0.1 - 0.8 parts by weight of isocyanate cross-linking agent, and 0.05 - 0.3 parts by weight of hindered phenol antioxidant, shear at 800 - 1200 rpm at 160 - 175°C for 40 - 60 min, and add the antioxidant 10 - 20 min before the end of shearing. Then cool down to 90 - 110°C, add 0.2 - 1.5 parts by weight of a composite emulsifier prepared by compounding sodium dodecyl benzene sulfonate and fatty alcohol polyoxyethylene ether at a mass ratio of 1:(0.5 - 2), and stir until the absolute value of Zeta potential ≤ 28 mV to obtain a highly stable modified asphalt; S04. Mix 100 parts by weight of water, 3 - 6 parts by weight of cationic emulsifier, and 0.5 - 3 parts by weight of pH regulator to obtain an alkaline soap solution with a pH between 10 - 12; S05. Preheat 55 - 65 parts by weight of the above highly stable modified asphalt to 85 - 95°C, and then circulate and grind it with 35 - 45 parts by weight of the soap solution through a colloid mill at 4000 - 6000 rpm for 3 - 5 times to obtain a modified emulsified asphalt.

2. The preparation method of a highly stable modified emulsified asphalt according to claim 1, characterized in that, The stabilizer is 0.5 - 3 parts by weight of nano-silica with a particle size of 20 - 50 nm or 0.5 - 3 parts by weight of montmorillonite stabilizer with an interlayer spacing of 1 - 3 nm.

3. A preparation method of a highly stable modified emulsified asphalt according to claim 2, characterized in that, The montmorillonite in the montmorillonite stabilizer is sodium-based montmorillonite with a cation exchange capacity ≥ 80 mmol / 100 g.

4. A preparation method of a highly stable modified emulsified asphalt according to claim 1, characterized in that The D90 particle size growth of the modified emulsified asphalt ≤ 12%, and the change rate of rotational viscosity at 25°C ≤ 15%.

5. The preparation method of a highly stable modified emulsified asphalt according to claim 1, characterized in that, The silane coupling agent is γ-aminopropyltriethoxysilane (KH550) or γ-(2,3-epoxypropoxy)propyltrimethoxysilane (KH560), and its dosage is 1.5 - 5 parts by weight.

6. A preparation method of a highly stable modified emulsified asphalt according to claim 1, characterized in that, The cross-linking agent is toluene diisocyanate (TDI) or hexamethylene diisocyanate (HDI), and the molar ratio of the cross-linking agent to the styrene unit in the styrene-butadiene latex is 1:(20 - 50).

7. The preparation method of the highly stable modified emulsified asphalt according to claim 1, characterized in that, The HLB value of the composite emulsifier is 10 - 14.

8. The preparation method of the highly stable modified emulsified asphalt according to claim 1, characterized in that, The mass ratio of the sodium dodecyl benzene sulfonate to the fatty alcohol polyoxyethylene ether is 1:(1 - 1.8).

9. The preparation method of the highly stable modified emulsified asphalt according to claim 1, wherein, The cationic emulsifier is cetyltrimethylammonium bromide (CTAB) or octadecyltrimethylammonium chloride (OTAC).

10. The preparation method of the highly stable modified emulsified asphalt according to claim 1, characterized in that, In the step S03, the shear rate is 1000 - 1200 rpm, the shear time is 50 - 60 min, and the antioxidant is pentaerythritol tetrakis [β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (Irganox 1010), and its addition time is 15 - 20 min before the end of shearing.

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