High-viscosity ultrathin surface cold-mixed emulsified asphalt, preparation method and construction method

Abstract

The invention discloses high-viscosity ultrathin surface cold-mixed emulsified asphalt, a preparation method and a construction method, and the preparation method comprises the following steps: pre-treating base asphalt to obtain activated asphalt; under a shearing condition, sequentially carrying out nano-enhancement and modification treatment on the activated asphalt to obtain a nano-enhanced modified asphalt matrix; adding a prefabricated reactive epoxy emulsion phase into the nano-reinforced modified asphalt matrix, emulsifying, and cooling to room temperature to obtain primary epoxy modified emulsified asphalt; and adding the pre-prepared elastomer composite water phase into the primary epoxy modified emulsified asphalt, and mixing to obtain the high-viscosity ultrathin surface cold-mixed emulsified asphalt. Various properties of the asphalt can be improved, and the defects that traditional asphalt is high in energy consumption, large in pollution and insufficient in performance can be overcome.

Description

Technical Field

[0001] This application belongs to the field of road engineering material preparation technology, specifically relating to a high-viscosity ultra-thin surface cold-mix emulsified asphalt, its preparation method and construction method. Background Technology

[0002] Traditional road asphalt materials mostly rely on hot-mix asphalt technology. This process requires mixing and applying asphalt and aggregates at high temperatures (usually above 150°C), which not only consumes a lot of energy but also emits harmful gases and dust, which is not in line with the trend of green and environmentally friendly development.

[0003] While the emerging cold-mix emulsified asphalt technology allows for construction at room temperature, reducing energy consumption and pollution, it generally suffers from problems such as low early strength, long molding cycle, insufficient adhesion to aggregates, and weak interlayer bonding. These issues make it difficult to meet the stringent requirements of high-grade roads for high strength, high toughness, and ultra-thin paving. Although some studies have attempted to improve performance by adding polymer modifiers or using composite emulsification technology, core challenges such as uneven dispersion of nanomaterials in asphalt, poor storage stability, slow curing speed, and difficulty in precisely controlling microstructure have not been effectively addressed, limiting the large-scale application of cold-mix emulsified asphalt in high-performance pavement engineering. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this application is to provide a high-viscosity ultra-thin surface cold-mix emulsified asphalt, its preparation method and construction method. This application aims to improve the various properties of asphalt to overcome the defects of traditional asphalt such as high energy consumption, high pollution and insufficient performance.

[0005] To achieve the above objectives, this application provides the following technical solution: A high-viscosity, ultra-thin, cold-mix emulsified asphalt, wherein the asphalt comprises the following components and their contents: composite binder: 14% to 18%; nano-reinforcing agent: 2% to 3%; bio-based tackifier: 1.5% to 2.5%; fast-setting cationic emulsifier: 0.8% to 1.2%; slow-setting nonionic emulsifier: 0.3% to 0.5%; stabilizer: 0.2% to 0.4%; defoamer: 0.1% to 0.2%; water-based epoxy curing agent: 4% to 5%; deionized water: 10% to 20%; base asphalt: balance.

[0006] This application also provides a method for preparing high-viscosity, ultra-thin, surface-mount cold-mix emulsified asphalt. The method includes: pretreating base asphalt to obtain activated asphalt; subjecting the activated asphalt to nano-reinforcement and modification treatments sequentially under shear conditions to obtain a nano-reinforced modified asphalt matrix; adding a pre-prepared reactive epoxy emulsifying phase to the nano-reinforced modified asphalt matrix, emulsifying it, and then cooling it to room temperature to obtain preliminary epoxy-modified emulsified asphalt; adding a pre-prepared elastomer composite aqueous phase to the preliminary epoxy-modified emulsified asphalt, and mixing to obtain high-viscosity, ultra-thin, surface-mount cold-mix emulsified asphalt.

[0007] Optionally, the pretreatment of the base asphalt to obtain activated asphalt includes: pre-dispersing the base asphalt to obtain premixed asphalt particles; performing primary melting on the premixed asphalt particles to obtain primary asphalt fluid; performing shear activation on the primary asphalt fluid to obtain activated asphalt fluid; and performing infrared heating on the activated asphalt fluid to obtain activated asphalt.

[0008] Optionally, the step of sequentially performing nano-reinforcement and modification treatments on activated asphalt under shear conditions to obtain a nano-reinforced modified asphalt matrix includes: pretreating the nano-reinforcer to obtain a nano-concentrated slurry; slowly adding the nano-concentrated slurry to activated asphalt to obtain a preliminary nano-composite asphalt matrix; ultrasonically treating the preliminary nano-composite asphalt matrix to obtain a preliminary nano-reinforced asphalt matrix; and modifying the preliminary nano-reinforced asphalt matrix to obtain a nano-reinforced modified asphalt matrix.

[0009] Optionally, the pretreatment of the nano-reinforcing agent to obtain the nano-concentrated slurry includes: performing a surface oleophilic treatment on the nano-reinforcing agent; and stirring the surface-oleophilic treated nano-reinforcing agent with a portion of the base asphalt to obtain the nano-concentrated slurry.

[0010] Optionally, the reactive epoxy emulsion phase is prepared by the following steps: heating a portion of deionized water; sequentially adding a slow-cracking nonionic emulsifier, a fast-cracking cationic emulsifier, and a stabilizer to the heated portion of deionized water, stirring until completely dissolved to form a reactive epoxy emulsion phase.

[0011] Optionally, the elastomer composite aqueous phase is prepared by the following steps: adding anionic styrene-butadiene rubber latex to the remaining deionized water and surface-activating the anionic styrene-butadiene rubber latex; constructing a hybrid shell layer on the surface of the surface-activated anionic styrene-butadiene rubber latex; and continuing to add defoamer to obtain the elastic composite aqueous phase.

[0012] Optionally, the surface activation of the anionic styrene-butadiene rubber latex includes: surface activation of the anionic styrene-butadiene rubber latex by adding an amphiphilic silane coupling agent.

[0013] Optionally, the construction of a hybrid shell on the surface of the surface-activated anionic styrene-butadiene rubber latex includes: pre-mixing nano-silica sol with an aqueous dispersion containing a bio-based thickener; and adding the pre-mixed nano-silica sol and the aqueous dispersion containing the bio-based thickener to deionized water containing the surface-activated anionic styrene-butadiene rubber latex.

[0014] This application also provides a construction method for high-viscosity ultra-thin surface cold-mix emulsified asphalt, comprising: pre-treating the road surface to be paved; simultaneously laying high-viscosity ultra-thin surface cold-mix emulsified asphalt and fiber mesh on the pre-treated road surface to be paved; magnetically arranging and initially activating the laid high-viscosity ultra-thin surface cold-mix emulsified asphalt; and curing the magnetically arranged and initially activated high-viscosity ultra-thin surface cold-mix emulsified asphalt.

[0015] Compared with the prior art, the beneficial effects of this application are as follows: This application, through innovative nano-reinforcement, epoxy resin composite and core-shell elastomer modification technology, can overcome the industry problems of low early strength, long molding cycle and poor interlayer adhesion of conventional cold-mix materials without relying on high-temperature construction, and ultimately improve the overall performance of asphalt materials. Attached Figure Description

[0016] Figure 1 This is a schematic flowchart of a method for preparing high-viscosity, ultra-thin surface cold-mixed emulsified asphalt according to an embodiment of this application; Figure 2 This is a schematic flowchart of a construction method for high-viscosity, ultra-thin surface cold-mixed emulsified asphalt provided in another embodiment of this application. Detailed Implementation

[0017] Specific embodiments of this application will now be described in detail with reference to the accompanying drawings. While specific embodiments of this application are shown in the drawings, it should be understood that this application can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of this application and to fully convey the scope of this application to those skilled in the art.

[0018] It should be noted that certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that different terms may be used to refer to the same component. This specification and claims do not distinguish components based on differences in terminology, but rather on differences in function. The terms "comprising" or "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising but not limited to". The following description in the specification outlines preferred embodiments of this application. The embodiments described herein are for the purpose of understanding the general principles of the specification and are not intended to limit the scope of this application. The scope of protection of this application shall be determined by the appended claims.

[0019] To facilitate understanding of the embodiments of this application, the following will provide further explanation and description with reference to the accompanying drawings and specific embodiments, and the accompanying drawings do not constitute a limitation on the embodiments of this application.

[0020] In one exemplary embodiment, this application provides a high-viscosity, ultra-thin surface cold-mix emulsified asphalt, wherein the asphalt comprises the following components and their contents: composite binder: 4% to 18% (6% to 8% anionic styrene-butadiene rubber latex and 8% to 10% waterborne epoxy resin); nano-reinforcing agent: 2% to 3% (nano-silica sol); bio-based tackifier: 1.5% to 2.5%; fast-setting cationic emulsifier: 0.8% to 1.2%; slow-setting nonionic emulsifier: 0.3% to 0.5%; stabilizer: 0.2% to 0.4%; defoamer: 0.1% to 0.2%; waterborne epoxy curing agent: 4% to 5%; deionized water: 10% to 20%; base asphalt: balance.

[0021] In another exemplary embodiment, such as Figure 1 As shown, this application also provides a method for preparing high-viscosity ultra-thin surface cold-mix emulsified asphalt, the method comprising the following steps: S100: pretreating base asphalt (such as 70# or 90# road petroleum asphalt) to obtain activated asphalt; S200: under shear conditions, performing nano-reinforcement and modification treatments on the activated asphalt sequentially to obtain a nano-reinforced modified asphalt matrix; S300: adding a pre-prepared reactive epoxy emulsified phase to the nano-reinforced modified asphalt matrix, emulsifying and cooling to room temperature to obtain preliminary epoxy-modified emulsified asphalt; S400: adding a pre-prepared elastomer composite aqueous phase to the preliminary epoxy-modified emulsified asphalt, mixing to obtain high-viscosity ultra-thin surface cold-mix emulsified asphalt.

[0022] This application describes a process where base asphalt is pretreated to obtain activated asphalt, then subjected to nano-reinforcement and modification under shear conditions to form a nano-reinforced matrix. A reactive epoxy emulsion phase is then introduced to construct a rigid network, and finally, a composite elastomer aqueous phase imparts toughness to the asphalt. This preparation method synergistically achieves high fluidity of asphalt at room temperature, excellent early and final strength, superior interlayer adhesion, and good crack resistance, overcoming the technical shortcomings of traditional cold-mix asphalt, such as slow molding, low strength, and poor adhesion.

[0023] In another exemplary embodiment, step S100, the pretreatment of the base asphalt to obtain activated asphalt, includes the following steps: S101: Pre-dispersion of solid or semi-solid base asphalt to obtain premixed asphalt particles; In this step, this application uses a screw feeder to crush and transport solid or semi-solid blocky base asphalt. At the feeder inlet, a micro-metering device is installed to uniformly spray a very small amount (approximately 0.01% to 0.05% of the total asphalt mass) of rheology modifier (such as organomontmorillonite or specific nanoclays) onto the surface of the base asphalt. During the propulsion and mixing process of the screw blades, the base asphalt and the nanoscale rheology modifier undergo sufficient physical contact and mixing, thereby obtaining premixed asphalt particles.

[0024] It should be noted that the purpose of this step is to achieve a preliminary homogenization, that is, to introduce functional additives while the base asphalt is still in a solid or semi-solid stage, thus laying the foundation for dispersion in the subsequent melting and activation processes. This avoids the problems of agglomeration and difficulty in uniform dispersion that easily occur when adding highly polar nanomaterials to liquid asphalt later. These uniformly distributed rheology modifier particles can act as crystal nuclei or cross-linking points in subsequent steps, enabling them to interact more effectively with the molten asphalt molecules, thereby macroscopically improving the asphalt's thixotropy, storage stability, and high-temperature deformation resistance.

[0025] S102: Primary melting of premixed asphalt particles to obtain primary asphalt fluid; In this step, the pre-dispersed asphalt particles are fed into an insulated pipe tightly surrounded by a medium-frequency electromagnetic coil (operating frequency 20 kHz to 50 kHz). When alternating current passes through the electromagnetic coil, a rapidly changing magnetic field is generated. This magnetic field can penetrate the asphalt particles and directly induce strong eddy currents inside them. These eddy currents rapidly generate heat due to the resistance of the asphalt particles themselves, thereby achieving the effect of simultaneously heating each particle inside the asphalt particles.

[0026] It should be noted that the purpose of this step is to achieve "volumetric heating," abandoning the traditional heating mode that relies on heat conduction and works from the outside in. This volumetric heating method can fundamentally eliminate the temperature gradient caused by thermal resistance, avoiding the problems of local overheating and carbonization ("coking") and the presence of unmelted nuclei inside ("half-cooked"). During the heating process, because heat can be generated directly inside the asphalt particles without loss, it has the characteristics of high thermal efficiency and rapid heating rate, which can significantly reduce the "thermal history" of the asphalt particles during the heating stage, thereby maximizing the preservation of the lightweight components and original properties of the asphalt particles. S103: Shear activation of primary asphalt fluid to obtain activated asphalt fluid; In this step, the primary asphalt fluid is fed into a static high-shear mixing unit. This unit contains multiple stages of vortex generators and shear grids with micron-sized slits and specially designed flow channels. When the primary asphalt fluid is forced through these extremely narrow channels under pressure, it experiences extremely high local shear rates (>10,000 s⁻¹). -1 This powerful, high-frequency mechanical shearing action can instantly act on every particle in the primary asphalt fluid, thus drastically intervening in the microstructure of the primary asphalt fluid.

[0027] It should be noted that the purpose of this step is to break down the large flocs and colloidal structures formed by the aggregation of asphalt molecules through intermolecular forces such as π-π bonds in the primary asphalt fluid into smaller, more uniformly distributed micro-units using high-frequency shear force, thereby reducing the internal structural viscosity of the primary asphalt fluid. Using a Brookfield rotational viscometer, the activated asphalt fluid obtained after this step showed a viscosity reduction of more than 40% compared to asphalt fluid prepared by traditional processes at the same temperature. Furthermore, this activated asphalt fluid achieved excellent flowability at a relatively low temperature range of 125°C to 130°C, and in some aspects even surpassed the levels achieved by traditional asphalt at a high temperature of 135°C. Therefore, it is easy to see that the activated asphalt fluid obtained after this step exhibits excellent flowability. S104: Activated asphalt fluid is heated by infrared radiation to obtain activated asphalt.

[0028] In this step, the activated asphalt fluid, after shearing, is fed into a gentle heating and heat preservation channel composed of a far-infrared ceramic emitting plate. Due to the unique penetrating power of far-infrared rays and their ability to match the vibrational frequency of organic molecules, the activated asphalt fluid can undergo gentle and uniform energy absorption, thereby precisely raising and stabilizing its temperature at the preset target process temperature (e.g., 125°C to 135°C).

[0029] It should be noted that far-infrared radiation heating is non-contact and avoids overheating, ensuring the uniformity of the final product temperature and providing stable conditions for subsequent processes (such as emulsification). Secondly, due to the efficiency of the preceding steps, the residence time of the activated asphalt fluid in this stage is minimized, reducing its accumulated "thermal history." This effectively inhibits the inevitable thermal oxidation and aging reaction of asphalt under long-term high temperatures, preserving its key chemical components. The resulting activated asphalt not only possesses good fluidity but also maintains excellent ductility and adhesion, thus providing a good matrix for road surface material manufacturing.

[0030] In another exemplary embodiment, step S200, wherein the activated asphalt is subjected to nano-reinforcement and modification treatments sequentially under shear conditions to obtain a nano-reinforced modified asphalt matrix, includes the following steps: S201: Pretreatment of nano-reinforcing agents (such as nano-silica (SiO2) or nano-alumina (Al2O3)) to obtain nano-concentrated slurry; In this step, the nano-reinforcing agent is first mixed with a small amount of polar organic solvent (such as isopropanol). The nano-reinforcing agent is premixed with a silane coupling agent (such as KH-550) in a high-speed disperser (the amount of polar organic solvent is 20% to 40% of the mass of the nano-reinforcing agent, and the amount of silane coupling agent is 1.0% to 2.5% of the mass of the nano-reinforcing agent). This operation can achieve chemical modification of the surface of the nano-reinforcing agent particles through the bridging of coupling agent molecules. For example, the polar organic solvent can wet and penetrate the initial agglomerates of nanoparticles, causing them to initially deagglomerate. Subsequently, the silane coupling agent is hydrolyzed under high-speed shear to generate silanol. Its hydrophilic end covalently condenses with the hydroxyl groups on the surface of the nanoparticles, while the long-chain alkyl groups at the hydrophobic end extend to the outside, thereby constructing a stable organic molecular layer on the surface of the nano-reinforcing agent particles. This lipophilic modification can reduce the surface energy of the nano-reinforcing agent particles, effectively inhibiting the re-agglomeration phenomenon caused by polarity differences when they are subsequently mixed with asphalt, while enhancing the interfacial compatibility and bonding force between the nano-reinforcing agent particles and the asphalt matrix. Secondly, the nano-reinforcing agent after surface oleophilization treatment is pre-stirred with a portion of the base asphalt (approximately 5% to 8% of the total amount) at 80°C to 90°C to form a nano-concentrated slurry.

[0031] It should be noted that the purpose of pretreating the nano-reinforcing agent is to modify its surface by using polar organic solvents and silane coupling agents to significantly reduce its extremely high surface energy. This effectively prevents the spontaneous aggregation of nanoparticles in the non-polar asphalt matrix due to van der Waals forces, ensuring that they can be uniformly dispersed in the form of individual nanoscale particles. Pretreating the nano-reinforcing agent lays a solid foundation for achieving nanoscale dispersion in activated asphalt, fully utilizing its reinforcing effect, and ultimately improving the mechanical properties and structural stability of the asphalt matrix.

[0032] It should also be noted that the surface-oil-affinity-treated nano-reinforcing agent is pre-stirred with a small amount of base asphalt at 80℃~90℃. The purpose is to utilize the suitable fluidity and wettability of the base asphalt within this temperature range, acting as a high-viscosity organic carrier. The shear force of mechanical stirring further disperses and dilutes the modified nano-reinforcing agent particles, thereby stably "fixing" the high-surface-energy nanopowder in the asphalt medium, forming a highly concentrated and storage-stable nano-masterbatch. This step effectively avoids localized agglomeration failure caused by uneven dispersion when directly adding the nano-reinforcing agent to a large amount of asphalt, ensuring that the nano-reinforcing agent exists in a highly dispersed state in the final asphalt product, thus preparing a precursor for subsequent large-scale uniform mixing.

[0033] S202: Slowly add nano-concentrated slurry to activated asphalt to obtain a preliminary nano-composite asphalt matrix; In this step, while the activated asphalt fluid is under high shear (e.g., using a high-speed, high-shear emulsifier with a rotation speed of 8000~12000 rpm), the nano-concentrated slurry is slowly added. This step aims to utilize the powerful hydraulic tearing force and turbulence generated by the intense shear flow field to instantly break up any remaining soft agglomerates of nanoparticles in the nano-concentrated slurry, and to achieve preliminary, macroscopic homogeneous mixing with the activated asphalt fluid.

[0034] S203: Ultrasonic treatment of the preliminary nanocomposite asphalt matrix to obtain a preliminary nano-reinforced asphalt matrix; In this step, after slowly adding the nano-concentrated slurry, a high-speed shearing state is maintained, and at the same time, the preliminary nano-composite asphalt matrix is ​​subjected to intermittent ultrasonic treatment (e.g., 5 seconds on, 2 seconds off) through an ultrasonic probe to grind the agglomerates of nanoparticles and achieve nanoscale dispersion.

[0035] In addition, during the shearing process, a trace amount of rheology modifier (such as organomontmorillonite) needs to be added to utilize the lamellar structure of the modifier to form a synergistic network with the nanoparticles, thereby enhancing the structural stability and thixotropy of the asphalt matrix.

[0036] S204: Modify the preliminarily nano-reinforced asphalt matrix to obtain a nano-reinforced modified asphalt matrix.

[0037] In this step, the shear state is adjusted from high speed to medium speed. At this time, the biomimetic mineralization inducer (the main agent is an amphiphilic block copolymer (such as polyethylene glycol-block-polyacrylic acid, PEG-b-PAA), the molecular structure of which is compatible with the asphalt oil phase at one end (PEG) and carries a large number of carboxyl negative charges at the other end (PAA); the auxiliary agent is a metal-organic framework precursor solution, such as an alcoholic solution of zinc nitrate) is slowly added to the preliminarily nano-reinforced asphalt matrix. Under these conditions, the inducer molecules will spontaneously self-assemble at the "asphalt-nanoparticle" interface to form an ordered monolayer template, thereby obtaining a templated pre-assembled asphalt matrix.

[0038] Furthermore, a trace amount (0.5%~1%) of deionized water is injected into the templated pre-assembled asphalt matrix. The water molecules instantly vaporize and are captured by the hydrophilic end of the inducer, thus forming tiny nanoreactors within the organic phase of the asphalt. Within the confined space of these nanoreactors, the MOF precursor Zn... 2+ First, it reacts with the inducing carboxyl group (-COO). - The nanoparticles coordinate with the silanol groups (-Si-OH) on the surface of the nano-silica under the catalysis of water vapor, and then undergo in-situ hydrolysis-condensation reaction to form a strong "Si-O-Zn" covalent bridge. Through this mechanism, the nano-silica particles are firmly anchored to the inducing agent template by covalent bonds, while the inducing agent is tightly bound to the asphalt molecular chain through physical entanglement and van der Waals forces. Ultimately, a three-dimensional rigid network with nanoparticles as nodes and covalent bonds as connecting ribs is constructed in situ inside the asphalt.

[0039] In another exemplary embodiment, in step S300, the reactive epoxy emulsion phase is prepared by the following steps: S301: Heating a portion of the deionized water; This step is the initial stage for preparing the reactive epoxy emulsion phase. The specific process is as follows: take a portion of deionized water (about 60% of the total water volume) and heat it to a preset temperature range (e.g., 40°C to 50°C).

[0040] It should be noted that the purpose of heating a portion of the deionized water in this embodiment is to reduce its surface tension and enhance its molecular thermal kinetic energy by raising its temperature. This creates efficient dissolution conditions for subsequently added solid or high-viscosity emulsifiers and stabilizers, which is beneficial for forming a homogeneous and stable emulsion system base liquid. Conversely, if the heating process is omitted and mixing is performed at room temperature, the dissolution rate of subsequently added slow-cracking nonionic emulsifiers, fast-cracking cationic emulsifiers, and other organic substances will decrease, or even fail to completely hydrate and dissolve, easily forming micro-aggregates invisible to the naked eye. In addition, the stabilizers added later are prone to rapid surface hydration and agglomeration in room-temperature deionized water, while their interior remains dry. This hinders their full swelling and the construction of a uniform three-dimensional stable network structure, resulting in poor stability of the final emulsion system. This can lead to a surge in the risk of demulsification, coarse emulsion particles, and deterioration of storage stability during subsequent emulsification with high-temperature asphalt.

[0041] S302: Add slow-cracking nonionic emulsifier, fast-cracking cationic emulsifier and stabilizer sequentially to the heated deionized water, and stir until completely dissolved to form a reactive epoxy emulsion phase.

[0042] In this step, slow-breaking nonionic emulsifiers (such as alkylphenol polyoxyethylene ethers and fatty alcohol polyoxyethylene ethers), fast-breaking cationic emulsifiers (such as alkyltrimethylammonium chloride and dialkyldimethylammonium chloride), and stabilizers (such as water-soluble polymers) are added sequentially to a portion of deionized water heated to a preset temperature, and stirred until completely dissolved to form a homogeneous aqueous matrix.

[0043] Subsequently, under continuous stirring, the formulated amounts of waterborne epoxy resin and waterborne epoxy curing agent were slowly and separately added. After the addition was complete, stirring was continued for 10 to 15 minutes to finally obtain a stable reactive epoxy emulsion phase.

[0044] It should be noted that, based on experimental verification, the specific order of adding the slow-cracking nonionic emulsifier, fast-cracking cationic emulsifier, and stabilizer must be strictly followed when preparing reactive epoxy emulsions. This is because this order optimizes the dissolution process and ensures the stability of the emulsion system. The first added slow-cracking nonionic emulsifier is insensitive to pH and ionic environments, allowing it to disperse uniformly in deionized water and form a stable, neutral framework. Subsequently, the fast-cracking cationic emulsifier, sensitive to ionic environments, is introduced within this framework. This effectively prevents flocculation or failure due to direct contact with potential trace impurities or localized high-concentration electrolytes, ensuring the integrity of its emulsifying function. Finally, the stabilizer is added, allowing it to swell better in the fully homogenized emulsifier solution and construct a three-dimensional network structure. This maximizes its effectiveness in preventing stratification and improving storage stability. Adding the stabilizer prematurely would severely hinder the diffusion and dissolution of the subsequent emulsifiers due to a sudden increase in system viscosity.

[0045] It should be noted that the reactive epoxy emulsifying phase added in this application serves to introduce a rigid three-dimensional network that can be subsequently cured, fundamentally improving the early strength, final strength, and durability of the asphalt. This emulsifying phase consists of waterborne epoxy resin and a matching curing agent (activated during the construction phase). When it is emulsified and mixed with the activated nano-reinforced asphalt matrix in step S300, epoxy microdroplets are uniformly dispersed in the continuous asphalt phase. During the final demulsification and curing stage, the epoxy resin and curing agent undergo a cross-linking reaction, forming a dense covalent network. This rigid network interpenetrates and synergistically interacts with the nano-reinforcement network in the asphalt, greatly enhancing the mixture's rutting resistance, shear strength, and hardness, and reducing its temperature sensitivity. This overcomes the fundamental defects of conventional emulsified asphalt, such as low early strength, reliance on water evaporation during molding, and easy softening at high temperatures.

[0046] In another exemplary embodiment, in step S400, the elastomer composite aqueous phase is prepared by the following steps: S401: Add anionic styrene-butadiene rubber latex to the remaining deionized water and perform surface activation on the anionic styrene-butadiene rubber latex; In this step, the remaining deionized water is added to a container equipped with a low-speed vortex stirrer, and anionic styrene-butadiene rubber latex is slowly added simultaneously. The mixture is stirred for 10 minutes to allow it to initially disperse evenly in the deionized water. Subsequently, under continuous stirring, an amphiphilic silane coupling agent (such as vinyltriethoxysilane, at an amount of 0.5% to 1.0% of the latex solids) is slowly added dropwise using a micro-injection pump. This coupling agent migrates to the surface of the anionic styrene-butadiene rubber latex particles and undergoes partial hydrolysis, enriching the surface of the anionic styrene-butadiene rubber latex particles with active sites such as vinyl groups and silanol groups, thereby completing the surface activation of the anionic styrene-butadiene rubber latex.

[0047] It should be noted that the method of slowly adding an amphiphilic silane coupling agent (such as vinyltriethoxysilane) to anionic styrene-butadiene rubber latex using a micro-injection pump in this embodiment has the advantage of achieving in-situ, mild, and precisely controllable interface engineering. Specifically, by strictly controlling the dropping rate and extremely low dosage (0.5% to 1.0% of the latex solids), the coupling agent molecules can fully migrate to the latex particle interface and undergo controllable hydrolysis, avoiding the risk of self-condensation and aggregation or latex demulsification caused by excessively high local concentrations. At the same time, the vinyl and silanol active sites generated in situ on the latex particle surface provide an ideal reaction platform for the subsequent construction of a stable "organic-inorganic hybrid shell" with inorganic phases such as nano-silica through covalent bonds. This is beneficial to enhancing the interfacial bonding strength and stability of the core-shell structure while preserving the latex's bulk properties to the maximum extent.

[0048] S402: Constructing a hybrid shell on the surface of anionic styrene-butadiene rubber latex after surface activation; In this step, the container is kept under low-speed vortex stirring. Nano-silica sol (particle size 10 nm to 20 nm, amount 2% to 4% of latex solids) is pre-mixed with an aqueous dispersion containing a bio-based thickener (such as rosin glycerol ester), and then slowly and uniformly added via a peristaltic pump to deionized water containing surface-activated anionic styrene-butadiene rubber latex. At this point, the nano-silica particles are guided and anchored to the surface of the activated anionic styrene-butadiene rubber latex particles through hydrogen bonding and electrostatic interactions. Subsequently, the pH of the deionized water containing the above substances is adjusted to weakly alkaline (pH = 8 to 9), and the temperature is slowly raised to 35°C to 40°C and aged for 30 minutes. Under these conditions, in-situ hydrolysis-condensation reactions occur between the silane coupling agent and the nano-silica, as well as between the nano-silica particles themselves, ultimately forming a dense, covalently bonded "organic-inorganic hybrid shell" on the surface of the styrene-butadiene rubber latex particles.

[0049] S403: Continue adding defoamer to obtain an elastic composite aqueous phase.

[0050] In this step, after the hybrid shell construction is completed, the stirring speed is further reduced to 150 rpm to 200 rpm to avoid damaging the core-shell structure already formed on the surface of the styrene-butadiene rubber latex particles. Then, the prescribed amount of defoamer is added, and the mixture is stirred for 20 to 30 minutes until all components are uniformly dispersed, finally obtaining a reinforced elastomer composite aqueous phase with a core-shell structure.

[0051] It should be noted that the role of the elastomer composite aqueous phase in this application is to endow the asphalt system with excellent toughness, elastic recovery ability, and fatigue crack resistance, achieving a material structure that combines rigidity and flexibility. This aqueous phase has anionic styrene-butadiene rubber latex with an organic-inorganic hybrid shell on its surface as its core. When mixed with the preliminarily epoxy-modified emulsified asphalt in step S400, these core-shell structured elastomer particles are uniformly distributed in the asphalt. When the asphalt is subjected to stress or temperature changes, these elastic particles can act as efficient stress absorption and dispersion centers, absorbing energy through their own deformation and effectively preventing the initiation and propagation of microcracks. This not only significantly improves the low-temperature crack resistance and impact resistance of the asphalt but also endows the pavement with excellent elastic recovery characteristics after heavy loads, avoiding the accumulation of permanent deformation. This compensates for the potential increase in brittleness that may result from a single epoxy system, ensuring the long-term durability of the ultra-thin layer under complex stress conditions.

[0052] To verify the effect of different components and their contents on the regulation of asphalt properties, this application provides the following preparation examples to clarify the structure-property relationship between components and properties.

[0053] Example 1: The components and contents of the high-viscosity ultra-thin surface cold-mix emulsified asphalt include: composite binder: 14%; nano-reinforcing agent: 2%; bio-based tackifier: 1.5%; fast-setting cationic emulsifier: 0.8%; slow-setting nonionic emulsifier: 0.3%; stabilizer: 0.2%; defoamer: 0.1%; water-based epoxy curing agent: 4%; deionized water: 10%; base asphalt: balance (approximately 67.1%).

[0054] The method for preparing high-viscosity, ultra-thin, cold-mixed emulsified asphalt based on the above components is as described above.

[0055] Example 2: This embodiment prepares high-viscosity, ultra-thin surface cold-mix emulsified asphalt based on the following components: composite binder: 16%; nano-reinforcing agent: 2.5%; bio-based tackifier: 2%; fast-setting cationic emulsifier: 1%; slow-setting nonionic emulsifier: 0.4%; stabilizer: 0.3%; defoamer: 0.15%; water-based epoxy curing agent: 4.5%; deionized water: 15%; base asphalt: balance (approximately 58.15%).

[0056] The method for preparing high-viscosity, ultra-thin, cold-mixed emulsified asphalt based on the above components is as described above.

[0057] Example 3 Composite binder: 18%; Nano-reinforcing agent: 3%; Bio-based tackifier: 2.5%; Fast-setting cationic emulsifier: 1.2%; Slow-setting nonionic emulsifier: 0.5%; Stabilizer: 0.4%; Defoamer: 0.2%; Waterborne epoxy curing agent: 5%; Deionized water: 20%; Base asphalt: Balance (approximately 49.2%).

[0058] The method for preparing high-viscosity, ultra-thin, cold-mixed emulsified asphalt based on the above components is as described above.

[0059] Furthermore, this application conducted performance tests on the high-viscosity ultra-thin paved cold-mix emulsified asphalt prepared based on Examples 1, 2, and 3. Specifically, the tests included: determining the workability of the activated asphalt using a Brookfield rotational viscometer; evaluating its initial and final strength using Marshall stability and compressive strength tests; quantifying interlayer bond strength using pull-out and shear tests; assessing low-temperature crack resistance using a bending beam rheometer (BBR) and low-temperature beam bending tests; verifying emulsion stability through storage stability tests (such as 5-day static tests); and measuring its compaction degree and resilient modulus by core sampling of paved test sections under the condition of controlling the paving thickness to ≤15mm. Additionally, the final strength before opening to traffic was verified using field load-bearing plate tests and the surface drying time method.

[0060] The specific detection and comparison results are shown in Table 1: Table 1

[0061] Among Examples 1, 2, and 3, Example 2 is considered the best example in this application due to its balanced component ratio and excellent overall performance. As shown in Table 1, the high-viscosity ultra-thin surface cold-mix emulsified asphalt prepared based on Example 2 exhibits excellent performance in key indicators such as early strength (10.5 kN Marshall stability), final compressive strength (6.5 MPa), interlayer bond strength (1.25 MPa), and low-temperature crack resistance (3200 µε). Furthermore, it demonstrates optimal emulsion storage stability (only 3.5% after 5 days) and a reasonable component ratio (e.g., 16% composite binder and 15% deionized water). This ensures high performance while also considering process feasibility and cost control, achieving an ideal balance between performance, stability, and engineering applicability.

[0062] Furthermore, this application compares the high-viscosity ultrathin-ply cold-mix emulsified asphalt prepared based on the method described in this application with traditional hot-mix asphalt and conventional cold-mix emulsified asphalt. The specific testing methods are as described above, and the test comparison results are shown in Table 2. Table 2

[0063] As shown in Table 2, the high-performance asphalt prepared by the method described in this application exhibits comprehensive superiority over asphalt prepared by traditional methods, achieving a synergistic breakthrough in strength, toughness, adhesion, and construction efficiency under ultra-thin paving conditions.

[0064] In another exemplary embodiment, such as Figure 2 As shown, this application also provides a construction method for high-viscosity, ultra-thin surface cold-mix emulsified asphalt, including the following steps: S1000: Pre-treatment of the road surface to be paved; In this step, firstly, a high-pressure (typically greater than 250 MPa) water jet is used to impact-clean the surface of the road, removing oil, dust, and loose particles, and forcefully opening the micropores of the road surface to form an active surface. Subsequently, it is essential to ensure the road surface is completely dry, as the water-based materials used later are extremely sensitive to moisture. On this basis, a surface activator is sprayed using specialized equipment. This agent, mainly composed of deionized water and a small amount of penetrating alcohol solvent, forms a molecular bridge between the old road surface and the new paving layer, reducing the demulsification barrier of the emulsified asphalt and enhancing the chemical bonding and physical adsorption between the old and new interfaces, preventing interlayer delamination from the source.

[0065] S2000: High-viscosity ultra-thin cold-mix emulsified asphalt and fiber mesh are laid simultaneously on the pretreated road surface to be paved. In this step, this application uses a synchronous paver with two hoppers and a fiber mesh laying system. As the paver moves forward, the front hopper precisely sprays atomized special high-viscosity cold-mix emulsified asphalt, forming a uniformly thick film on the old road surface. Immediately afterwards, the laying system in the middle smoothly presses a roll of pre-placed reinforcing fiber mesh into this emulsified asphalt film, ensuring complete impregnation. Simultaneously, the rear hopper evenly spreads single-size aggregate, surface-activated with a silane coupling agent, onto the asphalt-impregnated fiber mesh. The entire process is completed in one step, ensuring that the emulsified asphalt fully impregnates the fiber mesh and coats the aggregate, forming a composite structure of "emulsified asphalt-fiber mesh-aggregate".

[0066] S3000: Magnetically controlled arrangement and initial activation of high-viscosity ultra-thin cold-mix emulsified asphalt after paving; In this step, a mobile device equipped with a layout of electromagnetic coils is suspended above and moves synchronously above the formed "emulsified asphalt-fiber mesh-aggregate" composite structure, generating a spatial gradient magnetic field of precisely calculated intensity. Functionalized iron oxide nanoparticles dispersed in the emulsified asphalt respond strongly to this magnetic field, initiating directional movement and orderly arrangement, constructing countless tiny "magnetic chains" within the mixture. This process effectively removes air and free water from the composite structure, while the weak heat generated by the hysteresis effect raises the temperature of the composite structure to approximately 40°C. This not only accelerates the initial demulsification of the emulsified asphalt, but more importantly, the directional migration of the nanoparticles enriches them in the asphalt-aggregate and asphalt-fiber interface regions, thereby enhancing the mechanical properties of the interfacial transition zone.

[0067] S4000: Curing of high-viscosity ultra-thin cold-mixed emulsified asphalt after magnetron arrangement and initial activation.

[0068] In this step, after magnetization, the road surface is immediately irradiated with a high-power ultraviolet lamp vehicle. During irradiation, the specific wavelength of ultraviolet light emitted by the high-power ultraviolet lamp is first absorbed by the photoinitiator loaded in the fiber web and rapidly decomposes to generate highly active free radicals. These free radicals can precisely destroy the microcapsule shell encapsulating the waterborne epoxy curing agent, causing it to be released instantaneously at a specified location and time. The released curing agent can undergo a rapid cross-linking polymerization reaction with the surrounding magnetically pre-activated waterborne epoxy resin. Because the penetration depth of ultraviolet light in the material is limited and the energy decays exponentially from top to bottom, the curing reaction also follows a gradient from the surface to the inside. That is, a high-strength hard shell will first form on the surface of the road to be paved to support personnel and equipment, while the bottom will be cured over a longer period of time thanks to the continuous catalysis of the active substances diffused down from above and the magnetic nanoparticles, thus avoiding internal stress caused by overall synchronous shrinkage.

[0069] In summary, this application, by integrating magnetron sputtering nanoparticles and photo-induced gradient curing, enables the active design and precise control of the microstructure of high-viscosity ultrathin emulsified asphalt mixtures. Its function is to elevate the traditional passive cold-mix process into an intelligent and efficient active strengthening process. Through these construction methods, high-viscosity ultrathin emulsified asphalt can achieve excellent strength, toughness, and crack resistance even with extremely thin paving thicknesses (≤15mm). Furthermore, thanks to the photo-triggered curing mechanism, curing time is reduced from several hours to tens of minutes, thus achieving the goal of rapid paving completion.

[0070] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A high tack ultra-thin cold-applied emulsified asphalt, characterized by, The components and contents of the asphalt include: Composite binder: 14% to 18%; Nano-enhancing agent: 2% to 3%; Bio-based tackifier: 1.5% to 2.5%; Fast-cracking cationic emulsifier: 0.8% to 1.2%; Slow-cracking non-ionic emulsifier: 0.3% to 0.5%; Stabilizer: 0.2% to 0.4%; Defoaming agent: 0.1% to 0.2%; Water-based epoxy curing agent: 4% to 5%; Deionized water: 10% to 20%; Base asphalt: the balance.

2. A method for preparing a high-viscosity ultra-thin cold-applied emulsified asphalt, characterized by, The method includes: Pretreating the base asphalt to obtain activated asphalt; Under shearing conditions, sequentially performing nano-enhancing and modification treatment on the activated asphalt to obtain a nano-enhanced modified asphalt matrix; Adding a pre-prepared reactive epoxy emulsion phase to the nano-enhanced modified asphalt matrix, and after emulsification, reducing to room temperature to obtain a preliminary epoxy modified emulsified asphalt; Adding a pre-prepared elastomer composite aqueous phase to the preliminary epoxy modified emulsified asphalt, and after mixing, obtaining a high-viscosity ultra-thin pavement cold-mix emulsified asphalt.

3. The preparation method according to claim 2, characterized in that, The pretreatment of the base asphalt to obtain activated asphalt includes: Pretreating the base asphalt to obtain a premixed asphalt particle; Performing primary melting on the premixed asphalt particle to obtain a primary asphalt fluid; Performing shearing activation on the primary asphalt fluid to obtain an activated asphalt fluid; Performing infrared heating on the activated asphalt fluid to obtain activated asphalt.

4. The production method according to claim 2, characterized by, The sequential nano-enhancing and modification treatment on the activated asphalt under shearing conditions to obtain a nano-enhanced modified asphalt matrix includes: Pretreating the nano-enhancing agent to obtain a nano-concentrated slurry; Slowly adding the nano-concentrated slurry to the activated asphalt to obtain a preliminary nano-composite asphalt matrix; Performing ultrasonic treatment on the preliminary nano-composite asphalt matrix to obtain a preliminary nano-enhanced asphalt matrix; Performing modification treatment on the preliminary nano-enhanced asphalt matrix to obtain a nano-enhanced modified asphalt matrix.

5. The preparation method according to claim 4, characterized in that, The pretreatment of the nano-enhancing agent to obtain a nano-concentrated slurry includes: Performing surface lipophilization treatment on the nano-enhancing agent; Stirring the surface lipophilization treated nano-enhancing agent with part of the base asphalt to obtain a nano-concentrated slurry.

6. The preparation method according to claim 2, characterized in that, The reactive epoxy emulsion phase is prepared by the following steps: Heating part of the deionized water; Sequentially adding a slow-cracking non-ionic emulsifier, a fast-cracking cationic emulsifier, and a stabilizer to the heated part of the deionized water, stirring until completely dissolved to form a reactive epoxy emulsion phase.

7. The preparation method according to claim 2, characterized in that, The elastomer composite aqueous phase is prepared by the following steps: Adding an anionic styrene-butadiene rubber latex to the remaining part of the deionized water, and performing surface activation on the anionic styrene-butadiene rubber latex; Constructing a hybrid shell layer on the surface of the surface activated anionic styrene-butadiene rubber latex; Continuing to add a defoaming agent to obtain an elastomer composite aqueous phase.

8. The preparation method according to claim 7, characterized in that, The surface activation of the anionic styrene-butadiene rubber latex includes: Performing surface activation on the anionic styrene-butadiene rubber latex by dropwise adding an amphiphilic silane coupling agent.

9. The preparation method according to claim 7, characterized in that, The construction of a hybrid shell layer on the surface of the surface activated anionic styrene-butadiene rubber latex includes: Pre-mixing a nano-silica sol with a water dispersion containing a bio-based tackifier; A pre-mixed nanosilica sol is added to deionized water containing surface-activated anionic styrene-butadiene rubber latex with a water dispersion containing a bio-based tackifier.

10. A construction method of high-viscosity ultra-thin cold-applied emulsified asphalt, characterized by, The method comprises: pretreating the to-be-paved road surface; synchronously paving high-viscosity ultra-thin cold-mixed emulsified asphalt and a fiber mesh on the pretreated to-be-paved road surface; magnetically aligning and preliminarily activating the high-viscosity ultra-thin cold-mixed emulsified asphalt after paving; solidifying the high-viscosity ultra-thin cold-mixed emulsified asphalt after magnetic alignment and preliminary activation.

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