A toughened emulsified asphalt against shear and non-sticky wheel and a preparation method thereof

Abstract

This invention discloses a toughened emulsified asphalt with shear resistance and non-stick properties, and its preparation method. The emulsified asphalt is obtained by emulsifying composite asphalt and modified soap solution. The composite asphalt is obtained by shear extrusion of 70# base asphalt, 15# hard asphalt, active rubber powder, SBS modifier, water-soluble salt, and compatibilizer in a twin-screw extruder. This invention utilizes a twin-screw extruder to disperse active rubber powder, SBS modifier, and water-soluble salt in asphalt under the compatibilizing effect of the compatibilizer, forming a uniform composite asphalt, which significantly improves the interlaminar shear strength and low-temperature toughness of the emulsified asphalt. By dispersing water-soluble salt in the composite asphalt, when the composite asphalt is melted and emulsified with soap solution, the water-soluble salt dissolves rapidly, causing the agglomerated composite asphalt to quickly disperse into uniform, fine droplets, thereby obtaining a storage-stable emulsified asphalt. This overcomes the technical bottleneck of difficulty in dispersing and emulsifying rubber powder in the industry, reduces production costs, and improves production efficiency.

Description

Technical Field

[0001] This invention relates to compositions of asphalt materials, particularly to non-stick emulsified asphalt for wheels, and specifically to a toughened emulsified asphalt for shear-resistant non-stick wheels and its preparation method. Background Technology

[0002] Emulsified asphalt is produced by heating and liquefying asphalt, then dispersing it as fine droplets in a saponified aqueous phase to form an oil-in-water asphalt emulsion. Using asphalt emulsion for road construction eliminates the need for heating, allowing for spraying or mixing and paving at room temperature, greatly simplifying construction. However, ordinary emulsified asphalt is temperature-sensitive, becoming sticky at high temperatures. When the road surface temperature is ≥65℃, adhesion between the asphalt and the vehicle wheels can easily occur, affecting paving efficiency and damaging the bonding layer. If the interlayer bond is damaged or weakened, it will lead to a decrease in the overall load-bearing capacity of the asphalt pavement, eventually developing into defects such as interlayer peeling, shoving, and detachment, shortening the road's service life. Therefore, non-sticky emulsified asphalt has been developed and is widely used in road paving, repair, and maintenance.

[0003] According to publicly available technical data and actual engineering applications, the main technical routes for non-stick emulsified asphalt are: (1) Increasing the softening point of the evaporation residue of emulsified asphalt to ≥65℃ to achieve non-sticking. For example, adding a certain proportion of low-grade hard asphalt to the base asphalt can increase the softening point of the emulsified asphalt. However, low-grade hard asphalt is difficult to emulsify and store, and it is prone to brittleness at low temperatures, affecting the later pavement performance. The invention patent with publication number CN119775789A discloses a toughened non-stick modified emulsified asphalt and its preparation method. It uses the high softening point of 50# hard asphalt to increase the softening point, and at the same time adds elastomer modifier and reinforcing toughening agent to significantly improve the toughness of emulsified asphalt. (2) By adding modifier, a layer of isolation film is formed on the surface of the emulsified asphalt after evaporation, thereby achieving the effect of non-sticking. The invention patent with publication number CN115386237B discloses an emulsified asphalt composition for non-sticking to tires and its preparation method. The emulsified asphalt, by adding SBR latex or SBS latex modifier, has a high softening point on the surface of the adhesive layer, which can form a network layer structure on the surface of the emulsified asphalt adhesive layer to prevent it from sticking to the tire. (3) The dense solid interface film formed by modifying the asphalt emulsion droplets with nano-inorganic materials is not easily stuck to the tire. The invention patent with publication number CN116178974B discloses non-sticking emulsified asphalt, its preparation method and application. The dense solid interface film formed by uniformly embedding a layer of solid nano-SiO2 particles on the surface of the emulsified asphalt droplets with nano-SiO2 solves the problem of emulsified asphalt sticking to the tire.

[0004] Non-stick emulsified asphalt uses high-softening-point hard asphalt to increase the softening point, achieving the goal of non-sticking. However, its interlayer shear strength and low-temperature toughness also deteriorate. Currently, non-stick emulsified asphalt generally suffers from poor low-temperature toughness and insufficient interlayer shear strength (usually ≤1.9MPa), which easily leads to pavement shoving, spalling, rutting, and other defects in the later stages, seriously affecting the service life of the pavement. To obtain non-stick emulsified asphalt with high interlayer shear strength and low-temperature toughness, it is usually necessary to add a large amount of modifiers such as SBS latex. SBS latex modifiers are expensive and cannot be added in large quantities. Even if added in large quantities, when the SBS content exceeds 3%, it will cause a decrease in the stability of the emulsified asphalt, resulting in segregation or demulsification, which in turn reduces toughness.

[0005] To meet the needs of construction projects, while ensuring the non-stick properties of emulsified asphalt on wheels, it is also necessary to guarantee its interlayer shear strength, low-temperature flexibility, and relatively low overall cost. Recycled rubber powder from waste tires is inexpensive, readily available, and has significant potential for improving the softening point, toughness, and interlayer shear strength of emulsified asphalt under heavy loads. However, rubber powder has poor compatibility with asphalt, is prone to agglomeration, and its strong surface inertness makes emulsification difficult, which also reduces the storage stability of the emulsified asphalt. Summary of the Invention

[0006] To address the issue of emulsified asphalt sticking to wheels during high-temperature construction, and to ensure low-cost acquisition of non-stick emulsified asphalt with both high shear resistance and low-temperature toughness, this invention provides a toughened emulsified asphalt for shear-resistant non-sticking wheels, and further provides a method for preparing the toughened emulsified asphalt for shear-resistant non-sticking wheels.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A toughened emulsified asphalt with shear resistance and non-stick properties is obtained by emulsifying composite asphalt and modified soap solution at a mass ratio of (55-60):(40-45); wherein: The composite asphalt is obtained by shear-melt extrusion of 30-35 parts by weight of 70# base asphalt, 22-25 parts by weight of 15# hard asphalt, 3.0-5.0 parts by weight of active rubber powder, 2-2.5 parts by weight of SBS modifier, 2.0-2.5 parts by weight of water-soluble salt, and 0.5-1 parts by weight of compatibilizer in a twin-screw extruder. The modified soap solution comprises, by weight: 40-43 parts water, 0.5-1.2 parts emulsifier, 0.5-0.8 parts nano-inorganic powder, and an appropriate amount of pH acidity adjuster; the emulsifier is a quaternary ammonium salt cationic emulsifier; the pH acidity adjuster adjusts the pH value of the modified soap solution to 1.5-2.5.

[0008] Preferably, the ratio of 70# base asphalt to 15# hard asphalt in the composite asphalt is 35:22. 70# base asphalt is easily emulsified, has good low-temperature crack resistance, and can impart basic bonding properties to the emulsified asphalt, effectively improving the adhesion between pavement structural layers. 15# hard asphalt has a high softening point and low penetration, which can improve the high-temperature stability of the emulsified asphalt while reducing its viscosity during high-temperature construction, providing support for achieving non-sticky emulsified asphalt.

[0009] Preferably, the active rubber powder is a fine rubber powder that has passed through an 80-mesh sieve after plasma activation treatment. This fine rubber powder is obtained from recycled waste tires. Recycled waste tire rubber powder has a positive effect on improving the softening point, toughness, and interlayer shear strength of emulsified asphalt under heavy loads. However, rubber powder has poor compatibility with asphalt, is prone to agglomeration, and has a highly inert surface, making it difficult to participate in the emulsification reaction, resulting in high emulsification difficulty and reduced storage stability of the emulsified asphalt. As a key feature, this invention utilizes plasma to activate the rubber powder, etching active groups onto the surface of the rubber powder to effectively improve its compatibility with asphalt. With the aid of a compatibilizer, the active rubber powder, SBS modifier, and water-soluble salt are dispersed in the asphalt, further swelling the active rubber powder to form a homogeneous body, thereby enhancing the low-temperature toughness and shear strength of the emulsified asphalt. This significantly improves the ductility and elasticity of the evaporation residue of the emulsified asphalt, allowing the material to remain flexible even at low temperatures.

[0010] Preferably, the water-soluble salt is at least one of magnesium sulfate, magnesium chloride, and calcium chloride. By dispersing the water-soluble salt in the composite asphalt, when the composite asphalt is emulsified with an aqueous soap solution as a molten liquid, the water-soluble salt dissolves rapidly in water, causing the high-temperature composite asphalt liquid to quickly disperse into fine droplets, forming a stable emulsion.

[0011] Preferably, the SBS modifier is a star-shaped styrene-butadiene-styrene block copolymer (SBS) with a molecular weight of 150,000 to 300,000. Star-shaped SBS exhibits higher tear resistance and thermal stability. When hot-melt shear dispersed in emulsified asphalt, it provides higher toughness, enhances the elastic recovery and shear resistance of the emulsified asphalt, and synergistically works with reactive rubber powder to improve the interlaminar shear strength of the emulsified asphalt.

[0012] Preferably, the compatibilizer is EVA (ethylene-vinyl acetate copolymer).

[0013] Preferably, the nano-inorganic powder is at least one of nano-clay, nano-silica, nano-zinc oxide, nano-alumina, and nano-magnesium oxide. Soap solutions modified with nano-inorganic powder can promote the formation of a physical barrier at the oil-water interface, prevent particle aggregation, and synergistically improve the storage stability of the emulsion; simultaneously, it improves the softening point of the emulsified asphalt. Preferably, the quaternary ammonium salt cationic emulsifier is at least one of 1831 (octadecyltrimethylammonium chloride), 1631 (hexadecyltrimethylammonium chloride), N-dodecyl bisquaternary ammonium salt, and diamine-type quaternary ammonium salt. More preferably, a diamine-type quaternary ammonium salt, such as the commercially available BH-Z2 asphalt emulsifier (provided by Shandong Banghua Oil & Chemical Co., Ltd.), is used.

[0014] The cationic emulsifier used in the above-mentioned scheme of the present invention is suitable for acidic systems with a pH value of 1.5 to 2.5. It is a medium-crack type emulsifier, which can accelerate the demulsification speed and ensure that the emulsified asphalt demulsifies quickly during high-temperature construction and achieves a non-stick effect.

[0015] As a preferred option, diluted hydrochloric acid is used as a pH adjuster. A typical procedure is to dilute industrial hydrochloric acid (approximately 37% concentration) to 10% and use this as a pH adjuster. This solution is then slowly and intermittently added to the emulsified aqueous phase while stirring and monitoring the pH value in real time, until the pH value reaches 1.5–2.5.

[0016] The above-mentioned method for preparing toughened emulsified asphalt with shear resistance and non-stick properties includes the following steps: S1. Rubber powder activation pretreatment: Rubber powder that has passed through an 80-mesh sieve is placed into a plasma activation chamber; the activation temperature is set to 80-100℃ and the vacuum degree to 0.05MPa. The rubber powder is suspended by stirring and oxygen is used as the discharge gas to perform plasma activation treatment on the rubber powder for 10-20 minutes to obtain activated rubber powder for later use. S2. Preparation of composite asphalt: According to the formula, 70# base asphalt, 15# hard asphalt, activated rubber powder, SBS modifier, water-soluble salt, and compatibilizer are mixed evenly; the mixture is fed into a twin-screw extruder for continuous melt shear extrusion to obtain composite asphalt, which is then transported to an asphalt storage tank, heated to 170-175℃, and kept warm for later use. S3. Preparation of modified soap solution: Add water to the mixing container according to the formula, heat to 60-65℃ and turn on the stirrer, stirring at a speed of 500-1000 r / min; add emulsifier and nano inorganic powder to the water in sequence, and continue stirring and dispersing for 10-20 min; then slowly add pH acidity adjuster while stirring, monitor the pH value of the system in real time, and adjust the pH value to 1.5-2.5 to obtain modified soap solution, and keep it in a storage tank at 60-70℃ for later use. S4. Preparation of emulsified asphalt: Composite asphalt and modified soap solution are added to a shear emulsifier at a mass ratio of (55-60):(40-45) for emulsification. During the emulsification process, the temperature is controlled in real time by a radiator to ensure that the discharge temperature is ≤90℃ and to prevent boiling and demulsification. The mixture is stirred at a low speed of 50-100r / min and kept warm for 1-3 hours. The mixture is then transferred to a finished product storage tank to obtain a toughened emulsified asphalt that is shear resistant and does not stick to the wheel.

[0017] Preferably, the plasma activation box uses a plasma generator with a frequency of 40KHz and a power of 2KW, which introduces active functional groups on the surface of the powder material without damaging its internal structure.

[0018] Preferably, the twin-screw extruder is a co-rotating twin-screw extruder. A co-rotating twin-screw extruder has strong shearing, dispersion, melting, and conveying functions. Through strong shearing and melting dispersion, active rubber powder, SBS modifier, and water-soluble salts are dispersed in asphalt under the promotion of a compatibilizer. The asphalt further swells the active rubber powder, promoting the formation of a near-homogeneous phase, enhancing the cohesiveness of the emulsified asphalt binder, and improving interlayer shear strength.

[0019] Preferably, the temperature setting range of the twin-screw extruder is 110–120°C. Excessive temperature results in a lower viscosity of the extrusion system, affecting shear dispersion; excessively low temperature fails to ensure complete melting of SBS and the compatibilizer.

[0020] Preferably, the shear emulsifier is a homogenizer or a colloid mill. When using a homogenizer for emulsification, emulsification is performed at a shear rate of 8000–12000 r / min for 10–15 min; when using a colloid mill for emulsification, continuous feeding is performed at a shear rate of 2000–3000 r / min.

[0021] As a well-known technical bottleneck in the industry, high-temperature molten asphalt easily agglomerates into large droplets in the aqueous phase, leading to sedimentation, flocculation, or demulsification, affecting the storage stability of the emulsion. Especially when rubber powder or SBS is added to improve the shear strength and low-temperature toughness of the asphalt, the high dynamic viscosity not only makes emulsification difficult but also makes it easier for large particles to settle, flocculate, and aggregate, resulting in oil-water separation and a significantly shortened shelf life. This invention aims to obtain low-cost, non-stick emulsified asphalt with shear resistance and low-temperature toughening. It utilizes plasma to activate rubber powder, etching active groups onto the surface of the rubber powder to effectively improve its compatibility with asphalt. Through strong shear melting and dispersion, and with the aid of a compatibilizer, the active rubber powder, SBS modifier, and water-soluble salts are dispersed in the asphalt to form a homogeneous composite asphalt blend. The water-soluble salts are uniformly dispersed in the composite asphalt. When soap solution is added after the composite asphalt melts for emulsification, the rapid dissolution of the water-soluble salts causes the aggregated composite asphalt to quickly disperse into small, uniform droplets, significantly improving emulsification efficiency and preventing stratification during long-term storage.

[0022] The beneficial effects of the present invention, a shear-resistant, non-sticky toughened emulsified asphalt and its preparation method, are reflected in the following aspects: (1) This invention involves plasma-activating rubber powder and dispersing the active rubber powder and SBS modifier into asphalt using a twin-screw extruder under the compatibilizing effect of a compatibilizer, forming an integrated composite asphalt. This significantly improves the interlaminar shear strength and low-temperature toughness of the emulsified asphalt. The interlaminar shear strength of the emulsified asphalt after demulsification is ≥2.2MPa, reaching a maximum of 2.5MPa. The ductility at a low temperature of 5℃ is ≥60cm.

[0023] (2) In this invention, water-soluble salts are dispersed in composite asphalt. When soap solution is added for emulsification after the composite asphalt is melted, the water-soluble salts dissolve rapidly, causing the aggregated composite asphalt to disperse quickly into uniform and fine droplets, thereby obtaining emulsified asphalt with stable storage and a 5-day storage stability of ≤1.2%. This overcomes the technical bottleneck of the difficulty in dispersing and emulsifying rubber powder and SBS, reduces production costs, and improves production efficiency.

[0024] (3) The raw materials for the emulsified asphalt of this invention are readily available and can be supplied stably on a large scale, realizing the high-value utilization of waste tires. The production equipment does not require special customization and can be industrialized by simply modifying existing emulsified asphalt production lines. Attached Figure Description

[0025] To more clearly and concisely illustrate the technical solutions of the embodiments of this application, the process will be presented below in the form of accompanying drawings.

[0026] Figure 1 This is a simplified process diagram of the preparation of a shear-resistant, non-sticky toughened emulsified asphalt according to the present invention. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to specific embodiments and comparative examples. The embodiments are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0028] All the materials used in the following examples and comparative examples are commercially available in bulk. Unless otherwise specified, all auxiliary materials are conventionally available commercial raw materials. The basic properties of some of the raw materials used are as follows: 70# base asphalt: softening point 48.5°C, penetration at 25°C 72.5 (0.1mm).

[0029] 15# hard asphalt: softening point 73.2°C, penetration at 25°C 15.8 (0.1mm).

[0030] SBS modifier: YH-801, star-shaped SBS, molecular weight 280,000, Baling Petrochemical.

[0031] Fine rubber powder: recycled rubber powder from waste tires, completely passing through an 80-mesh sieve, with less than 5% residue on a 100-mesh sieve.

[0032] Quaternary ammonium salt cationic emulsifier: 1831 (octadecyltrimethylammonium chloride).

[0033] Diamine-type quaternary ammonium salt cationic emulsifier: BH-Z2, provided by Shandong Banghua Oil & Fat Chemical Co., Ltd.

[0034] Example 1 S1. Rubber powder activation pretreatment: 10 kg of fine rubber powder that has passed through an 80-mesh sieve was placed in a plasma activation chamber. The plasma generator had a frequency of 40 kHz and a power of 2 kW. The activation temperature was set to 100 ℃ and the vacuum degree to 0.05 MPa. The rubber powder was suspended by stirring and oxygen was used as the discharge gas. The rubber powder was subjected to plasma activation treatment for 20 minutes to obtain activated rubber powder for later use. S2. Preparation of composite asphalt: Mix 32 kg of 70# base asphalt, 23 kg of 15# hard asphalt, 4 kg of activated rubber powder, 2.5 kg of SBS modifier, 2.5 kg of magnesium sulfate, and 1.0 kg of EVA evenly; feed the mixture into a co-rotating twin-screw extruder and continuously melt, shear, and disperse it at 120°C to obtain composite asphalt. Then, transport the mixture to an asphalt storage tank, heat it to 170°C, and keep it warm for later use. S3. Preparation of modified soap solution: Add 43 kg of clean water to a mixing container, heat to 60°C and turn on the stirrer, stirring at 1000 r / min; add 0.8 kg of quaternary ammonium salt cationic emulsifier 1831 and 0.5 kg of nano zinc oxide to the water in sequence, and continue stirring and dispersing for 10 min; dilute industrial hydrochloric acid (approximately 37% concentration) to 10% as a pH acidity adjuster, and slowly add it to the emulsified aqueous phase while stirring and monitoring the pH value in real time until the pH value reaches 1.5, to obtain the modified soap solution, and keep it warm in a storage tank at 65°C for later use; S4. Preparation of emulsified asphalt: Composite asphalt and modified soap solution were added to a homogenizer at a mass ratio of 60:40 and emulsified at a shear rate of 8000 r / min for 10 min. During the emulsification process, the temperature was controlled in real time by a radiator to ensure that the discharge temperature was ≤90℃ to prevent boiling and demulsification. The mixture was then transferred to a curing tank and stirred at a low speed of 100 r / min and kept warm for 3 h. Finally, it was transferred to a finished product storage tank to obtain a shear-resistant, non-sticky, toughened emulsified asphalt.

[0035] Comparative Example 1 When implementing the scheme of Example 1, no water-soluble salts are added to the composite asphalt. The remaining ingredients and processes are carried out in accordance with Example 1.

[0036] Example 2 S1. Rubber powder activation pretreatment: 10 kg of fine rubber powder that has passed through an 80-mesh sieve was placed in a plasma activation chamber. The plasma generator had a frequency of 40 kHz and a power of 2 kW. The activation temperature was set to 80 ℃ and the vacuum degree to 0.05 MPa. The rubber powder was suspended by stirring and oxygen was used as the discharge gas. The rubber powder was subjected to plasma activation treatment for 20 minutes to obtain activated rubber powder for later use. S2. Preparation of composite asphalt: Mix 30 kg of 70# base asphalt, 25 kg of 15# hard asphalt, 3 kg of activated rubber powder, 2 kg of SBS modifier, 2 kg of calcium chloride, and 0.8 kg of EVA evenly; feed the mixture into a co-rotating twin-screw extruder and continuously melt, shear, and disperse it at 110°C to obtain composite asphalt, which is then transported to an asphalt storage tank, heated to 170°C, and kept warm for later use. S3. Preparation of modified soap solution: Add 40 kg of clean water to a mixing container, heat to 65°C and turn on the stirrer, stirring at 500 r / min; add 0.5 kg of diamine-type quaternary ammonium salt cationic emulsifier BH-Z2 and 0.5 kg of nano silica to the water in sequence, and continue stirring and dispersing for 10 min; dilute industrial hydrochloric acid (approximately 37% concentration) to 10% as a pH acidity adjuster, and slowly add it to the emulsified aqueous phase while stirring and monitoring the pH value in real time until the pH value reaches 2.5, to obtain the modified soap solution, and keep it warm in a storage tank at 70°C for later use; S4. Preparation of emulsified asphalt: Composite asphalt and modified soap solution were added to a colloid mill at a mass ratio of 58:42 and continuously fed at a shear rate of 3000 r / min for emulsification. During the emulsification process, the temperature was controlled in real time by a radiator to ensure that the discharge temperature was ≤90℃ to prevent boiling and demulsification. The mixture was then transferred to a curing tank and stirred at a low speed of 50 r / min for 2 hours and kept warm for curing. Finally, it was transferred to a finished product storage tank to obtain a shear-resistant, non-sticky, toughened emulsified asphalt.

[0037] Comparative Example 2 In the implementation of Example 2, the composite asphalt was prepared directly by heating and stirring, without using a screw extruder for shear dispersion. The remaining ingredients and processes were carried out according to Example 2.

[0038] Example 3 S1. Rubber powder activation pretreatment: 10 kg of fine rubber powder that has passed through an 80-mesh sieve was placed in a plasma activation chamber. The plasma generator had a frequency of 40 kHz and a power of 2 kW. The activation temperature was set to 100 ℃ and the vacuum degree to 0.05 MPa. The rubber powder was suspended by stirring and oxygen was used as the discharge gas. The rubber powder was subjected to plasma activation treatment for 15 minutes to obtain activated rubber powder for later use. S2. Preparation of composite asphalt: Mix 35 kg of 70# base asphalt, 22 kg of 15# hard asphalt, 5 kg of activated rubber powder, 2 kg of SBS modifier, 2 kg of magnesium chloride, and 0.5 kg of EVA evenly; feed the mixture into a twin-screw extruder rotating in the same direction and continuously melt, shear, and disperse it at 115°C to obtain composite asphalt, which is then transported to an asphalt storage tank, heated to 175°C, and kept warm for later use. S3. Preparation of modified soap solution: Add 43 kg of clean water to a mixing container, heat to 65°C and turn on the stirrer, stirring at 500 r / min; add 0.8 kg of quaternary ammonium salt cationic emulsifier 1831 and 0.8 kg of nano clay to the water in sequence, and continue stirring and dispersing for 10 min; dilute industrial hydrochloric acid (approximately 37% concentration) to 10% as a pH acidity adjuster, and slowly add it to the emulsified aqueous phase while stirring and monitoring the pH value in real time until the pH value reaches 2.0, to obtain the modified soap solution, and keep it warm in a storage tank at 70°C for later use; S4. Preparation of emulsified asphalt: Composite asphalt and modified soap solution were added to a homogenizer at a mass ratio of 55:45 and emulsified at a shear rate of 8000 r / min for 10 min. During the emulsification process, the temperature was controlled in real time by a radiator to ensure that the discharge temperature was ≤90℃ to prevent boiling and demulsification. The mixture was then transferred to a curing tank and stirred at a low speed of 50 r / min and kept warm for 1 hour. Finally, it was transferred to a finished product storage tank to obtain a shear-resistant, non-sticky, toughened emulsified asphalt.

[0039] Comparative Example 3 When implementing the scheme of Example 3, the rubber powder activation pretreatment step is omitted, and it is directly used in step S2 to prepare composite asphalt. The remaining ingredients and processes are carried out in accordance with Example 3.

[0040] Comparative Example 4 When implementing the scheme of Example 3, in step S2, the twin-screw extruder is melt-extruded at 150°C, and the remaining ingredients and processes are carried out in accordance with Example 3.

[0041] Comparative Example 5 When implementing the scheme of Example 3, no compatibilizer is added in step S2. The remaining ingredients and processes are carried out in accordance with Example 3.

[0042] The performance of the emulsified asphalt obtained in the above embodiments and comparative examples was compared through performance testing. Tests were conducted in accordance with JTG 3410-2025 (Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering), T / CHTS 10037-2021 (Technical Guidelines for Construction of Non-stick Emulsified Asphalt Tack Coating), and relevant standards of ASTM C882 / C882M. The results are shown in Tables 1 and 2.

[0043] Table 1: Performance test results of emulsified asphalt in Examples 1-2 and Comparative Examples 1-2 By comparing Example 1 and Comparative Example 1, it can be found that by pre-dispersing water-soluble salts in the composite asphalt, the water-soluble salts dissolve rapidly when soap solution is added for emulsification, which greatly promotes the dispersion of the composite asphalt into fine droplets, thereby obtaining emulsified asphalt with stable storage.

[0044] A comparison between Example 2 and Comparative Example 2 reveals that when rubber powder and asphalt are not sheared and dispersed in a twin-screw extruder, the compatibility between asphalt and rubber powder is limited, and a uniform blend cannot be formed. When soap solution is added for emulsification, the droplet uniformity is poor, which has a certain impact on storage stability and shear strength.

[0045] Table 2. Performance test results of emulsified asphalt in Examples 3 and 3-5 By comparing Example 3 with Comparative Examples 3, 4, and 5, it can be found that: in Comparative Example 3, the rubber powder was not activated, and when soap solution was added for emulsification, the droplet uniformity was poor, which had a certain impact on storage stability and shear strength; in Comparative Example 4, a higher temperature (150°C) was used for shear dispersion in a twin-screw extruder, which reduced the shear dispersion performance to a certain extent, affecting the formation of a uniform phase between activated rubber powder, SBS, and asphalt, and thus affecting storage stability and shear strength; in Comparative Example 5, the absence of a compatibilizer had a certain impact on the storage stability and interlayer shear strength of the emulsified asphalt.

[0046] In summary, the toughened emulsified asphalt of this invention exhibits shear resistance and non-stick properties, ensuring stable storage and a high interlayer shear strength of up to 2.5 MPa. Furthermore, it demonstrates high ductility at low temperatures (5°C) and excellent bonding toughness, effectively resisting pavement distress and extending service life. This is primarily based on activating the active groups of rubber powder, which, under the influence of a compatibilizer, shear and disperse with asphalt in an extruder to form a homogeneous composite asphalt, significantly improving the interlayer shear strength and toughness of the emulsified asphalt. In particular, by pre-dispersing water-soluble salts in the composite asphalt, the salts dissolve rapidly upon the addition of soap solution for emulsification, greatly promoting the dispersion of the composite asphalt into fine droplets, thus obtaining a storage-stable emulsified asphalt. This overcomes the engineering bottlenecks of difficulty in emulsification and unstable storage caused by adding rubber powder.

[0047] It should be noted that although the above embodiments have been described in detail with reference to preferred solutions, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application, all of which fall within the protection scope of the application.

Claims

1. A toughened emulsified asphalt with shear resistance and non-stick properties, characterized in that, The toughened emulsified asphalt is obtained by emulsifying composite asphalt and modified soap solution at a mass ratio of (55-60):(40-45); wherein: The composite asphalt is obtained by shear-melt extrusion of 30-35 parts by weight of 70# base asphalt, 22-25 parts by weight of 15# hard asphalt, 3.0-5.0 parts by weight of active rubber powder, 2-2.5 parts by weight of SBS modifier, 2.0-2.5 parts by weight of water-soluble salt, and 0.5-1 parts by weight of compatibilizer in a twin-screw extruder. The modified soap solution comprises, by weight: 40-43 parts water, 0.5-1.2 parts emulsifier, 0.5-0.8 parts nano-inorganic powder, and an appropriate amount of pH acidity adjuster; the emulsifier is a quaternary ammonium salt cationic emulsifier; the pH acidity adjuster adjusts the pH value of the modified soap solution to 1.5-2.

5.

2. The toughened emulsified asphalt for shear resistance and non-sticking to wheels according to claim 1, characterized in that, The ratio of 70# base asphalt to 15# hard asphalt in the composite asphalt is 35:

22.

3. The toughened emulsified asphalt for shear resistance and non-sticking to wheels according to claim 1, characterized in that, The active rubber powder is a fine rubber powder that has passed through an 80-mesh sieve and undergone plasma activation treatment.

4. The toughened emulsified asphalt for shear resistance and non-sticking as described in claim 1, characterized in that, The water-soluble salt is at least one of magnesium sulfate, magnesium chloride, and calcium chloride.

5. The toughened emulsified asphalt for shear resistance and non-sticking to wheels according to claim 1, characterized in that, The SBS modifier is selected from star-shaped SBS with a molecular weight of 150,000 to 300,000.

6. The toughened emulsified asphalt for shear resistance and non-sticking to wheels according to claim 1, characterized in that, The compatibilizer is an ethylene-vinyl acetate copolymer.

7. The toughened emulsified asphalt for shear resistance and non-sticking to wheels according to claim 1, characterized in that, The nano-inorganic powder is at least one of nano-clay, nano-silica, nano-zinc oxide, nano-alumina, and nano-magnesium oxide.

8. The toughened emulsified asphalt for shear resistance and non-sticking to wheels according to claim 1, characterized in that, The quaternary ammonium salt cationic emulsifier is selected from at least one of octadecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, N-dodecyl bisquaternary ammonium salt, and diamine quaternary ammonium salt.

9. A method for preparing the toughened emulsified asphalt for shear-resistant, non-sticky wheels according to any one of claims 1 to 8, characterized in that, Includes the following steps: S1. Rubber powder activation pretreatment: Rubber powder that has passed through an 80-mesh sieve is placed into a plasma activation chamber; the activation temperature is set to 80-100℃ and the vacuum degree to 0.05MPa. The rubber powder is suspended by stirring and oxygen is used as the discharge gas to perform plasma activation treatment on the rubber powder for 10-20 minutes to obtain activated rubber powder for later use. S2. Preparation of composite asphalt: According to the formula, 70# base asphalt, 15# hard asphalt, activated rubber powder, SBS modifier, water-soluble salt, and compatibilizer are mixed evenly; the mixture is fed into a twin-screw extruder for continuous melt shear extrusion to obtain composite asphalt, which is then transported to an asphalt storage tank, heated to 170-175℃, and kept warm for later use. S3. Preparation of modified soap solution: Add water to the mixing container according to the ratio, heat to 60-65℃ and turn on the stirrer, stirring at a speed of 500-1000 r / min; add emulsifier and nano inorganic powder to the water in sequence, and continue stirring and dispersing for 10-20 minutes. Then slowly add the pH acidity adjuster while stirring, monitor the pH value of the system in real time, adjust the pH value to 1.5-2.5 to obtain the modified soap solution, and keep it in a storage tank at 60-70℃ for later use. S4. Preparation of emulsified asphalt: Composite asphalt and modified soap solution are added to a shear emulsifier at a mass ratio of (55-60):(40-45) for emulsification. During the emulsification process, the temperature is controlled in real time by a radiator to ensure that the discharge temperature is ≤90℃ and to prevent boiling and demulsification. The mixture is stirred at a low speed of 50-100r / min and kept warm for 1-3 hours. The mixture is then transferred to a finished product storage tank to obtain a toughened emulsified asphalt that is shear resistant and does not stick to the wheel.

10. The preparation method according to claim 9, characterized in that, The twin-screw extruder is a co-rotating twin-screw extruder; the temperature setting range of the twin-screw extruder is 110-120℃; the shear emulsifier is a homogenizer or a colloid mill.

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