High-performance warm-mixing high-modulus dense water pavement structure and preparation method thereof

Abstract

The invention relates to the technical field of road engineering, in particular to a high-performance warm-mixing high-modulus dense water pavement structure and a preparation method thereof. The waterproof bonding layer is prepared by mixing an epoxy resin main agent, a microencapsulated amine curing agent, a functional diluent and filler according to the mass ratio of (50-60): (25-35): (5-8): (12-18), and the filler is expanded vermiculite powder; the mixture lower layer is prepared by mixing a high modulus agent, a lower layer warm mixing agent, asphalt, aggregate and mineral powder according to the mass ratio of (0.4-0.8): (0.3-1.1): (5-6.5): (80-85): (2-5); the high-modulus agent is prepared by mixing POE (Polyolefin Elastomer), modified sepiolite, an interfacial compatibilizer and an anti-aging agent according to the mass ratio of (72-78): (16-20): (4-6): (1-2); a non-stick wheel bonding layer; preparing a mixture upper layer; a curing agent is added into epoxy resin in a microcapsule mode, construction heat triggers microcapsule breaking to achieve accurate epoxy curing, molten POE forms a barb structure in vermiculite gradient pores, sepiolite fibers puncture to construct an anchor chain framework, the three components cooperate to eliminate an interface weak area, and stripping resistance is improved in a leap-over mode.

Description

Technical Field

[0001] The present invention relates to the technical field of road engineering, and in particular to a high-performance warm-mix high-modulus water-tight paving structure and a preparation method thereof. Background Art

[0002] The pavement structure is the core structure in road engineering that directly bears loads and environmental effects. Especially in scenarios such as highway tunnels, it must take into account multiple functions such as low-carbon construction, structural bearing stiffness, waterproof sealing, and fire safety.

[0003] Inadequate interlayer bonding in highway tunnel pavement has long been a technical challenge plaguing the industry. Traditional epoxy resin waterproofing adhesive layers, when used in warm-mix processes, suffer from low crosslink density and poor matrix density due to insufficient curing temperature, preventing effective synergy with the underlying mix. Furthermore, the interface between the two layers relies primarily on physical adsorption or simple chemical bonding, which can easily lead to stress concentration under heavy traffic and temperature stresses, inducing microcracks and forming water seepage channels. Water intrusion further weakens the bond, accelerates interlayer delamination, and significantly shortens the pavement's service life.

[0004] The information disclosed in this background technology section is only intended to deepen the understanding of the overall background technology of the present invention and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art known to those skilled in the art. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a high-performance warm-mix high-modulus water-dense paving structure and a preparation method. The curing agent is added to the epoxy resin in the form of microcapsules. The construction heat triggers the microcapsules to rupture and realizes precise curing of the epoxy. The molten POE forms a barb structure in the gradient pores of the vermiculite, and the sepiolite fiber punctures to construct the anchor chain skeleton. The above three work together to eliminate the weak area of ​​the interface, and the anti-peeling performance is greatly improved.

[0006] The first object of the present invention is to provide a high-performance warm-mix high-modulus water-tight paving structure, the paving structure is as follows from bottom to top:

[0007] Concrete leveling layer; more specifically, the concrete leveling layer adopts C30 / C35 / C40 ordinary concrete;

[0008] Waterproof bonding layer: prepared by mixing epoxy resin main agent, microencapsulated amine curing agent, functional diluent and filler in a mass ratio of 50-60:25-35:5-8:12-18, and the filler is expanded vermiculite powder;

[0009] More specifically, when triggered by the heat of paving the lower layer of the mixture, the microcapsules rupture and release polyetheramine and isophorone diamine, which then quickly initiate a cross-linking reaction of the epoxy resin to form a dense three-dimensional network matrix, thereby improving the bonding strength and deformation resistance of the waterproof bonding layer, while enhancing the interlayer waterproof sealing and structural durability. Among them, polyetheramine can accelerate the curing speed, and isophorone diamine can improve the toughness and impact resistance of the cured product. The combination of the two can improve the comprehensive mechanical properties of the bonding layer while ensuring curing efficiency.

[0010] Mixture lower layer: prepared by mixing high modulus agent, lower layer warm mix agent, asphalt, aggregate and mineral powder in a mass ratio of 0.4-0.8:0.3-1.1:5-6.5:80-85:2-5; high modulus agent is POE (ethylene-octene copolymer), modified sepiolite, interfacial compatibilizer and anti-aging agent in a mass ratio of 72-78:16-20:4-6:1-2;

[0011] More specifically, POE, as an elastic polymer matrix, can significantly enhance the mixture's deformation resistance and toughness, effectively resisting permanent deformation caused by temperature stress and heavy traffic. Silane coupling agent-modified sepiolite, as a nano-reinforcement phase, can be evenly dispersed and form a network skeleton through its high aspect ratio structure and interface modification effect, thereby improving the mixture's modulus and crack resistance. The interfacial compatibilizer improves the compatibility between the components, reduces interface defects, and enhances the overall structural synergy.

[0012] More specifically, the interfacial compatibilizer can be EAA (ethylene-acrylic acid copolymer);

[0013] More specifically, the lower layer warm mix agent includes at least a polyethylene glycol-polypropylene glycol block copolymer. The polyethylene glycol segment (hydrophilic end) and the polypropylene glycol segment (hydrophobic end) of the copolymer can form a directional adsorption layer at the asphalt interface, significantly reducing the surface tension of the asphalt, so that the asphalt can present a low-viscosity flow state at around 120°C, reducing the mixing temperature by 30 to 50°C compared with traditional hot mixing, and simultaneously reducing VOCs emissions by more than 40%; its block structure has excellent compatibility with the POE elastic matrix. While reducing the viscosity of the asphalt, it does not interfere with the penetration process of the molten POE into the pores of the expanded vermiculite, ensuring the formation of barbed mechanical locks.

[0014] In addition to polyethylene glycol-polypropylene glycol block copolymer, the lower warm mix agent also includes interface enhancement auxiliary agents, etc.

[0015] Non-stick wheel adhesive layer;

[0016] upper layer of mixed material;

[0017] During the construction process, the present invention sequentially spreads the concrete leveling layer, waterproof bonding layer, mixture lower layer, non-stick wheel bonding layer and mixture upper layer from bottom to top. When spreading the mixture lower layer, the mixing temperature can be reduced to about 120°C due to the effect of the lower layer warm mixing agent.

[0018] When the lower layer of the mixture paved at about 120°C contacts the waterproof bonding layer, its heat conduction triggers the microcapsule to rupture, and the released polyetheramine / isophorone diamine composite curing agent triggers the epoxy resin cross-linking reaction to form a dense three-dimensional network matrix; at the same time, driven by gravity, the molten POE penetrates along the gradient pores unique to expanded vermiculite powder (10-20 μm narrow diameter at the entrance / 50-100 μm wide cavity inside). During the cooling process, POE shrinks at the pore neck to form a 5-15 μm thin neck, and expands and solidifies in the wide cavity area to form a 40-80 μm wide cavity. At the same time, the silane-modified sepiolite fiber uses its sharp end to pierce the vermiculite pore wall under the paving vibration stress, penetrates the POE anchor body to form a vertical anchor chain skeleton, and its surface silane group is chemically bonded with the epoxy resin to strengthen the interface. The three simultaneously construct an interlocking system of barbed mechanical lock, fiber anchor chain reinforcement and chemical bonding reinforcement, so that the interlayer interface forms a gradually strengthened zone, and the shear resistance is gradiently distributed, which effectively overcomes the peeling failure caused by sudden interface stress in traditional paving.

[0019] As a preferred embodiment of the present invention, the main agent is a mixture of hydrogenated bisphenol A epoxy resin with an epoxy value of 0.38-0.45eq / 100g and o-cresol epoxy resin with a softening point of 85-95°C in a mass ratio of 6-7:3-4.

[0020] More specifically, hydrogenated bisphenol A epoxy resin gives the system good toughness and weather resistance, while o-cresol epoxy resin improves bonding strength with its high reactivity and cross-linking density. After the two are compounded, under the triggering of polyetheramine / isophorone diamine curing agent, they can quickly form a dense three-dimensional network structure to enhance the cohesion of the waterproof bonding layer, and when paving the lower layer of warm-mix high-modulus asphalt, they can synergize with the barbed locks and fiber skeleton formed by POE and silane-modified sepiolite to further strengthen the chemical bonding and mechanical anchoring of the interlayer interface, thereby improving the durability and anti-peeling performance of the overall paving structure.

[0021] As a preferred embodiment of the present invention, the expansion multiple of the expanded vermiculite powder is ≥15 times, and the particle size is 50-100 μm.

[0022] More specifically, the high expansion ratio gives the vermiculite powder rich gradient pores, which provides an ideal space for the molten POE to penetrate and solidify to form barbed mechanical locks, significantly improving the pull-out resistance between layers.

[0023] The particle size of 50 to 100 μm is compatible with silane-modified sepiolite fibers, making it easier for the fibers to pierce the pore walls under paving vibration and penetrate the POE anchor body to form a vertical anchor chain skeleton. At the same time, the rigid particles of vermiculite powder can enhance the modulus of the epoxy resin bonding layer, and work together with the lower layer of the mixture to improve the overall strength and deformation resistance of the paving structure.

[0024] As a preferred embodiment of the present invention, the core material of the microencapsulated amine curing agent is composed of polyetheramine and isophoronediamine in a mass ratio of 4:1 to 3, and the capsule wall is embedded with ethyl cellulose.

[0025] More specifically, ethyl cellulose has excellent thermal stability and chemical inertness. It can stably encapsulate the polyetheramine and isophorone diamine core materials at room temperature, preventing premature reaction between the curing agent and the epoxy resin main agent and ensuring the storage stability of the material. When the heat generated by the paving of the lower layer of warm-mix high-modulus asphalt mixture is transferred to the waterproof bonding layer, the ethyl cellulose capsule wall will soften and break, accurately releasing the curing agent, triggering the epoxy resin cross-linking reaction, and achieving temperature-triggered curing.

[0026] Ethyl cellulose has good film-forming properties, and the 0.5-1 μm thin wall formed can be evenly dispersed in the epoxy resin system without affecting the mixing uniformity of the main agent and filler. Its biocompatibility and low toxicity meet the environmental protection requirements of road materials.

[0027] As a preferred embodiment of the present invention, the preparation method of the curing agent comprises:

[0028] Mixing polyetheramine and isophorone diamine, stirring at 60-70° C. until the mixture becomes homogeneous, to obtain a core material;

[0029] Dissolve ethyl cellulose in a mixed solvent of acetone and ethyl acetate to prepare a wall material solution with a concentration of 15 to 20 wt%;

[0030] The core material and the wall material solution are mixed in a mass ratio of 1:0.8 to 1.2, and shear emulsified to form an emulsion;

[0031] Deionized water is slowly added dropwise to the emulsion to obtain a suspension, and the suspension is spray-dried to obtain a curing agent.

[0032] In the above preparation method, constant temperature stirring at 60-70°C allows the polyetheramine and isophorone diamine to be fully miscible, ensuring the uniformity of the core material's reaction activity and avoiding uneven cross-linking reactions after the release of the curing agent; deionized water suspension treatment and spray drying process can reduce the introduction of impurities and accurately control the particle size distribution of the microcapsules, resulting in excellent dispersibility in the epoxy resin main agent.

[0033] As a preferred embodiment of the present invention, a method for preparing modified sepiolite comprises:

[0034] The fibrous sepiolite is calcined at 450°C ± 10°C and, after cooling, airflow-pulverized to a D50 particle size of ≤10μm. More specifically, calcination removes surface adsorbed water, organic impurities, and interlayer crystallization water of the sepiolite, exposing more silanol active sites while optimizing the fiber crystal structure and enhancing surface reactivity. Airflow-pulverization to a D50 of ≤10μm maximizes the specific surface area by controlling the particle size, providing sufficient anchoring interfaces for subsequent silane coupling agent grafting and ensuring uniform dispersion in the epoxy resin matrix, forming a dense fiber puncture network.

[0035] The silane coupling agent is mixed with anhydrous ethanol, an acetic acid-water solution is added dropwise, and hydrolysis is carried out under magnetic stirring at 50°C ± 2°C to obtain a hydrolyzate; more specifically, the pH value is adjusted by acetic acid to promote the hydrolysis of silane molecules into silanols, forming active intermediates that can condense with hydroxyl groups on the surface of sepiolite;

[0036] The crushed sepiolite is added to the hydrolysis solution and transferred to high-pressure conditions for reaction. More specifically, the high-pressure environment forces the hydrolyzed silane coupling agent to penetrate into the micropores of the sepiolite fiber, where Si-OH condenses with the hydroxyl groups on the surface of the sepiolite to form Si-O-Si covalent bonds, thereby achieving firm grafting of the coupling agent on the fiber surface. The high pressure also promotes the dissociation of the sepiolite fiber bundles, preventing agglomeration and dispersing them in a single filament state, laying the foundation for the subsequent formation of a fiber anchor chain structure in the asphalt pavement layer.

[0037] The reaction product was filtered, pre-dried at 80°C, vacuum-dried at 120°C, and heat-treated at 180°C to obtain modified sepiolite.

[0038] More specifically, pre-drying at 80°C removes most of the free water to prevent fiber adhesion after filtration; vacuum drying at 120°C removes residual ethanol and hydrolysis byproducts in a low-oxygen environment to prevent organic residues from affecting compatibility with epoxy resin;

[0039] 180℃ heat treatment: The chemical bond between the silane coupling agent and sepiolite is further strengthened through thermal activation, while the grafted layer on the fiber surface is densified. This ensures that when the silane coupling agent is dispersed in the epoxy resin main agent, the organic functional groups of the silane coupling agent can undergo synergistic cross-linking with curing agents such as polyetheramine, thereby enhancing the dual effects of chemical bonding and mechanical puncture at the interface between the layers.

[0040] As a preferred embodiment of the present invention, the aspect ratio of the modified sepiolite is ≥20:1.

[0041] More specifically, the high aspect ratio gives the sepiolite fiber a stronger puncture ability, which makes it easy to penetrate the pore wall of expanded vermiculite under the vibration stress of paving, and pass through the barbed anchor body formed by the curing of POE, thereby constructing a dense vertical anchor chain skeleton; at the same time, the slender fiber has a large specific surface area, and the contact sites between the silane groups on the surface and the epoxy resin increase, strengthening the interfacial chemical bonding effect; in addition, the high aspect ratio fiber is easier to form a three-dimensional network dispersed structure in the asphalt mixture, and cooperates with the POE elastic matrix to improve the crack resistance and structural stiffness of the lower layer of warm-mix high modulus asphalt, ensuring that after puncturing the vermiculite pores, it mechanically locks and chemically bonds with the barbs to form a three-dimensional interlocking system, significantly enhancing the shear resistance and durability between layers.

[0042] As a preferred embodiment of the present invention, the functional diluent is 1,4-butanediol diglycidyl ether.

[0043] More specifically, 1,4-butanediol diglycidyl ether can not only effectively reduce the viscosity of the epoxy resin main agent and improve the coating uniformity during scraping or spraying, but also participate in the cross-linking reaction with the two epoxy groups it contains, avoiding the problem of strength loss after curing caused by inactive diluents; its molecular structure has excellent compatibility with hydrogenated bisphenol A epoxy resin and o-cresol epoxy resin, and can promote the dispersion uniformity of the main agent and expanded vermiculite powder filler, ensuring the formation of a continuous and dense three-dimensional network matrix after curing; under the heat triggering of the warm-mix asphalt layer paving, the diluent reacts synergistically with the polyetheramine / isophorone diamine curing agent, enhancing the cross-linking density while improving the flexibility and impact resistance of the bonding layer, and together with the mechanical lock formed by POE penetrating into the vermiculite pores and the anchor chain effect of the sepiolite fiber, construct a rigid and flexible interface structure, significantly enhancing the interlayer bonding strength and peeling resistance of the waterproof bonding layer.

[0044] As a preferred embodiment of the present invention, the antioxidant is hindered phenols.

[0045] As a preferred embodiment of the present invention, the non-stick wheel adhesive layer includes cationic emulsified asphalt and stone chips, and the emulsifier of the cationic emulsified asphalt is compounded by alkylbenzene sulfonate and fatty amine polyoxyethylene ether in a mass ratio of 2:1-1.2.

[0046] More specifically, the compound emulsifier synergistically improves the construction adaptability of emulsified asphalt, allowing the cationic emulsified asphalt to quickly demulsify after uniform spraying at room temperature, forming a continuous and tough bonding film, effectively preventing the wheels from sticking to the lower layer of asphalt when paving the upper layer of the mixture, ensuring smooth construction; at the same time, the spread stone chips are embedded in the bonding film, forming a rough embedded structure on the surface of the non-stick wheel bonding layer, which not only prevents the emulsified asphalt film from being over-densified due to wheel rolling, but also provides a mechanical anchoring site for the subsequent paving of the upper layer of the mixture, ensuring that the interface between layers has appropriate bonding strength and friction resistance, meeting the requirements of construction convenience and structural functionality.

[0047] As a preferred embodiment of the present invention, the upper layer of the mixture is prepared by mixing a flame retardant, an upper layer warm mix agent, modified asphalt, aggregate and activated alumina ore powder in a mass ratio of 1-2:2-4:4-6.5:84-90:5-10;

[0048] The modified asphalt is based on road petroleum asphalt and is mixed with 1.5-2.5wt% of single-walled carbon nanotubes;

[0049] The upper warm-mix agent is a compound system formed by a non-ionic surfactant containing phosphorus oxygen groups and a quaternary ammonium salt in a mass ratio of 4-6:1-4.

[0050] More specifically, in the upper layer of the mixture, the flame retardant gives the pavement structure fire-retardant properties to meet the safety requirements of special scenarios; the upper layer of warm mix agent reduces the mixing temperature of the asphalt mixture through a compounding system, reduces energy consumption and harmful substance emissions, and ensures uniform coating of asphalt and aggregate; single-walled carbon nanotube modified asphalt improves the strength and toughness of the asphalt matrix and enhances the crack resistance of the mixture; the aggregate constitutes a skeleton structure and provides embedded support; activated alumina mineral powder is used as a filler to fill the voids and together with the aggregate forms a dense gradation, improving the water-tightness and surface wear resistance of the upper layer. The various components work synergistically and cooperate with the lower interlocking system to construct a pavement structure that is both functional and durable.

[0051] As a preferred embodiment of the present invention, the thickness of the concrete leveling layer is 50-100 mm; the thickness of the waterproof bonding layer is 0.5-0.7 mm; the thickness of the lower layer of the mixture is 80-100 mm; the thickness of the non-stick wheel bonding layer is 0.4-0.8 mm; and the thickness of the upper layer of the mixture is 25-35 mm.

[0052] A second object of the present invention is to provide a method for preparing the above-mentioned high-performance warm-mix high-modulus water-tight pavement structure, comprising:

[0053] Concrete leveling layer: Use formwork to support 50-100mm thick concrete, vibrate and compact it, then cover and maintain it, roughening it to a roughness of less than 1mm. The roughening treatment provides a solid and suitable attachment base for the waterproof bonding layer, ensuring the initial bonding strength of the interface.

[0054] Waterproof bonding layer: Mix the components according to the mass ratio, apply on the concrete leveling layer, and let it stand at room temperature to solidify;

[0055] Lower layer of mixture: heat the aggregate and asphalt in sequence, add high modulus agent and lower layer warm mix agent and mix to obtain the mixture, spread and compact on the waterproof bonding layer to obtain the lower layer of mixture;

[0056] Non-stick wheel bonding layer: Spray cationic emulsified asphalt evenly on the surface of the lower layer of the mixture, and then spread 0.3-0.6mm particle size stone chips;

[0057] Upper layer of mixture: After mixing the flame retardant, upper warm mix agent, modified asphalt, aggregate and activated alumina ore powder, spread it on the surface of the non-stick wheel bonding layer at a speed of 2 to 3 m / min, and perform static pressing, kneading and final pressing in turn.

[0058] Compared with the prior art, the present invention has the following beneficial effects: when the lower layer of warm-mix high-modulus asphalt paved at high temperature contacts the waterproof bonding layer, its heat conduction triggers the rupture of ethyl cellulose microcapsules, and the released polyetheramine / isophorone diamine composite curing agent triggers the epoxy resin cross-linking reaction to form a dense three-dimensional network matrix; at the same time, the molten POE penetrates along the gradient pores unique to expanded vermiculite powder under gravity drive, and during the cooling process, the POE shrinks at the pore neck to form a thin neck of 5 to 15 μm, and expands and solidifies in the wide cavity area to form a 40 to 80 μm The anchor head constructs a barbed mechanical lock with doubled pull-out resistance; at the same time, the silane-modified sepiolite fiber uses its sharp end to pierce the vermiculite pore wall under the paving vibration stress, penetrates the POE anchor body to form a vertical anchor chain skeleton, and its surface silane group is chemically bonded with the epoxy resin to strengthen the interface. The three simultaneously construct an interlocking system of barbed mechanical lock, fiber anchor chain reinforcement and chemical bonding reinforcement, so that the interlayer interface forms a gradually strengthened zone, and the shear resistance is gradiently distributed, which effectively overcomes the peeling failure caused by sudden changes in interface stress in traditional paving. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 It is a structural schematic diagram of the present invention;

[0060] Markings in the attached figure: 1. Concrete leveling layer; 2. Waterproof bonding layer; 3. Lower layer of mixture; 4. Non-stick wheel bonding layer; 5. Upper layer of mixture. DETAILED DESCRIPTION

[0061] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0062] The substances used in the specific implementation methods are all obtained through market procurement;

[0063] Example 1:

[0064] This embodiment provides a high-performance warm-mix high-modulus water-tight paving structure, which comprises, from bottom to top:

[0065] Concrete leveling layer 1: Use C30, C35 or C40 ordinary concrete, crushed stone particle size 5-31.5mm, sand content 35%-40%, water-binder ratio 0.4-0.45;

[0066] Waterproof bonding layer 2:

[0067] Main agent: 65% of hydrogenated bisphenol A epoxy resin with an epoxy value of 0.38-0.45eq / 100g and 35% of o-cresol epoxy resin with a softening point of 85-95°C; accounting for 52wt%.

[0068] Curing agent: polyetheramine and isophorone diamine (mass ratio 4:1.5) are embedded in ethyl cellulose microcapsules, the microcapsule wall thickness is 0.5-1 μm, and the proportion is 26wt%.

[0069] Functional diluent: 1,4-butanediol diglycidyl ether, accounting for 7wt%.

[0070] Filler: expanded vermiculite powder with an expansion ratio of ≥15 times and a particle size of 50 to 100 μm, accounting for 13wt%.

[0071] The preparation method of the curing agent is:

[0072] Stir polyetheramine and isophorone diamine at 60-70°C for 30 minutes until homogeneous;

[0073] 18% ethyl cellulose was dissolved in acetone-ethyl acetate (volume ratio 1:1) and stirred at 50°C until completely dissolved;

[0074] The core material and wall material solutions were mixed in a ratio of 1:1, and shear emulsified (8000 r / min, 5 min) to form an emulsion. Deionized water was added dropwise to a solid content of 20%, and the mixture was spray-dried (inlet air temperature 180°C, atomization pressure 0.3 MPa) to obtain microcapsules.

[0075] Mixture lower layer 3:

[0076] High modulus agent: accounts for 0.6wt% of the mixture, and the specific components are:

[0077] POE (ethylene-octene copolymer) 75 wt%;

[0078] Silane-modified sepiolite (aspect ratio 25:1, D50 ≤ 10 μm) 18 wt%;

[0079] EAA interfacial compatibilizer 5wt%;

[0080] Hindered phenol antioxidant Irganox1010 2wt%.

[0081] Lower layer warm mix agent: polyethylene glycol-polypropylene glycol block copolymer, accounting for 4wt% of the asphalt mass, with 0.2% interface strengthening adjuvant, accounting for about 0.7wt% of the mixture as a whole.

[0082] Asphalt: Base asphalt with a viscosity of 200 Pa·s at 60°C, mixed with 6.5wt% (base asphalt) of SBS modifier, accounting for 6wt% of the total mass of the mixture.

[0083] Aggregate: Limestone crushed stone (particle size 4.75-19mm) and manufactured sand (0-4.75mm), with strict grading conforming to AC-20C, accounting for 82.6wt%, of which 4.75-19mm crushed stone accounts for 68wt%, and 0-4.75mm manufactured sand accounts for 32wt%.

[0084] Mineral powder: ground limestone powder, with a 0.075mm sieve aperture passing rate of 92%, accounting for 3.4wt%.

[0085] The preparation method of modified sepiolite is as follows:

[0086] The fibrous sepiolite was calcined at 455 °C for 2.5 h and then pulverized by air flow to a D50 of ≤10 μm;

[0087] Silane coupling agent KH-550 and anhydrous ethanol were mixed in a ratio of 1:5.5, 5% acetic acid aqueous solution accounting for 10% of the total mass was added dropwise, and magnetic stirring was performed at 52°C for 35 minutes to obtain a hydrolyzed solution;

[0088] Sepiolite and hydrolyzate were mixed in a mass ratio of 1:3.2 and reacted at 125°C and 1.2 MPa under high pressure for 2.2 h. The reaction product was filtered and then pre-dried at 80°C for 2.5 h, vacuum-dried at 120°C for 4.5 h, and heat-treated at 180°C for 1.2 h to obtain modified sepiolite.

[0089] Non-stick wheel adhesive layer 4:

[0090] Cationic emulsified asphalt, with a thickness of 0.6 mm, is prepared by weighing alkylbenzene sulfonate and fatty amine polyoxyethylene ether in a mass ratio of 2:1.2, adding them to hot water at 50-60°C (water accounts for 42% of the total mass of the emulsified asphalt), and stirring at 2000 rpm for 15 minutes until the emulsifier is completely dissolved to form a light yellow transparent aqueous solution;

[0091] Heat the base asphalt to 140-150°C to melt, slowly pour it into the emulsifier aqueous solution at a solid content of 58%, and high-speed shear it at 3000r / min in a colloid mill for 20 minutes to obtain cationic emulsified asphalt with a particle size of 1-5μm, which is stored in a 50°C insulation tank for later use.

[0092] Mixture top layer 5:

[0093] Flame retardant: The dosage is 1.5wt%, and aluminum hydroxide powder with an average particle size of ≤5μm is selected. It is dried in an oven at 105℃ for 4h in advance to remove surface adsorbed water to avoid affecting the asphalt coating.

[0094] Preparation of modified asphalt (5.5 wt%): The base asphalt (viscosity 200 Pa·s at 60°C) was heated to 160°C to melt, and single-walled carbon nanotubes (diameter 1-2 nm, length 10-30 μm) were added at a ratio of 1.8 wt%. The asphalt was sheared using a high-speed shearing machine (12,000 rpm) for 30 minutes, followed by ultrasonic dispersion at 60°C and 50 kHz for 20 minutes to form a uniformly dispersed nano-modified asphalt, which was then stored in an insulated tank at 140°C for use.

[0095] Compounding of the upper warm mix agent (dosage is 2.3wt%): weigh a non-ionic surfactant containing phosphorus oxygen groups (such as polyoxyethylene alkyl phosphate) and a quaternary ammonium salt (such as dodecyltrimethylammonium chloride) in a mass ratio of 5:3, add to 50°C hot water and stir to dissolve, prepare an aqueous solution with a solid content of 20%, and cool to room temperature for use.

[0096] Aggregate (85wt%): basalt crushed stone with a particle size of 2.36-9.5mm;

[0097] Activated alumina ore powder (dosage is 9wt%): 0.075mm sieve hole pass rate ≥95%.

[0098] The preparation method of the above-mentioned high-performance warm-mix high-modulus water-tight pavement structure includes:

[0099] Construction of concrete leveling layer 1: Use steel formwork to support 80mm thick C35 concrete, vibrate it to denseness and cover it for 7 days, then use a shot blasting machine to roughen it to a roughness of 0.6mm.

[0100] Construction of waterproof bonding layer 2: Mix the main agent, curing agent, functional diluent and filler according to the above mass ratio, apply with a toothed scraper, control the thickness to 0.6mm, and let it stand at room temperature for 35 minutes to solidify.

[0101] Construction of the lower layer 3 of the mixture: Heat the aggregate to 145°C and the asphalt to 135°C. Add the high modulus agent and the lower layer warm mix agent and mix for a total of 100 seconds at a temperature of 125°C. Use a paver at a speed of 2.5m / min and compact with a combination of steel and rubber-wheel rollers to ensure a compaction degree of 98.5% and a thickness of 30mm.

[0102] During the construction of the non-stick wheel bonding layer 4, the cationic emulsified asphalt is evenly sprayed on the surface of the mixture lower layer 3 with a spraying thickness of 0.6 mm, and then stone chips with a particle size of 0.3 to 0.6 mm are spread.

[0103] Upper layer 5 of the mixture: After uniformly mixing the flame retardant, upper warm mix agent, modified asphalt, aggregate and activated alumina ore powder, spread them on the surface of the non-stick wheel bonding layer at a speed of 2 to 3 m / min. Use a 13t double steel wheel roller for static compaction, a 16t rubber wheel roller for kneading, and a 13t double steel wheel roller for final compaction to ensure that the compaction degree meets the design requirements.

[0104] Example 2:

[0105] The difference from Example 1 is that the dosage of the high modulus agent is adjusted, and the dosages of the other substances are adaptively adjusted:

[0106] High modulus agent: accounts for 0.8% of the mixture, the specific components are:

[0107] POE (ethylene-octene copolymer) 77%;

[0108] Silane-modified sepiolite (aspect ratio 25:1, D50 ≤ 10 μm) 16%;

[0109] EAA interfacial compatibilizer 5.5%;

[0110] Hindered phenol antioxidant Irganox1010 1.5%.

[0111] Example 3:

[0112] The difference from Example 1 is that the main agent is adjusted and the dosage of other substances is adaptively adjusted:

[0113] Main agent: 68% of hydrogenated bisphenol A epoxy resin with an epoxy value of 0.38 to 0.45eq / 100g and 32% of o-cresol-formaldehyde epoxy resin with a softening point of 85 to 95°C; accounting for 52%.

[0114] Comparative Example 1:

[0115] The difference from Example 1 is that unexpanded vermiculite powder is used instead of expanded vermiculite powder.

[0116] Comparative Example 2:

[0117] The difference from Example 1 is that a mixed system of polyetheramine and isophorone diamine is directly used, and ethyl cellulose is not used for embedding into microcapsules.

[0118] Comparative Example 3:

[0119] The difference from Example 1 is that unmodified sepiolite (not calcined, not treated with a silane coupling agent) is used instead of the silane-modified sepiolite.

[0120] The following tests were performed on the examples and comparative examples to obtain the data in Table 1:

[0121] 1. Bond strength between the waterproof bonding layer and the lower layer of the mixture: Refer to the T0624-2000 standard in the "Test Procedure for Asphalt and Asphalt Mixtures in Highway Engineering" (JTGE20-2021), and use a pull-out test to measure the vertical pull-out strength between the waterproof bonding layer and the lower layer of the mixture. The test temperature is 25°C and the loading rate is 100 kPa / s.

[0122] 2. Test the dynamic stability of the pavement structure: According to the T0719-2011 standard of the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTGE20-2021), a rutting tester is used for testing at a temperature of 60°C and a load of 0.7 MPa.

[0123] 3. Water tightness of the pavement structure: Referring to the T0730-2000 standard in the "Test Procedure for Asphalt and Asphalt Mixtures in Highway Engineering" (JTGE20-2021), use a water permeability meter to measure the water permeability coefficient of the upper layer. The test temperature is 20°C. In the embodiment, the water permeability coefficient should be ≤30mL / min.

[0124] Table 1: Test results of Examples and Comparative Examples

[0125]

[0126] In Examples 1-3, the microcapsule curing agent precisely cross-links the epoxy resin under the heat triggering of warm-mix asphalt to form a dense three-dimensional network; the gradient porosity of the expanded vermiculite induces the POE to solidify into a barbed mechanical lock, and the silane-modified sepiolite fiber pierces the vermiculite pores with a high aspect ratio to construct the anchor chain skeleton and form a chemical bond with the epoxy resin; the optimized distribution ratio of each component further enhances the interlayer bonding, anti-rutting and water-tightness properties.

[0127] Comparative Example 1 uses unexpanded vermiculite powder, which has insufficient porosity and coarse particle size, and cannot provide space for POE to penetrate and form barbed anchor bodies. The mechanical locking mechanism is missing, and it only relies on physical bonding of epoxy resin, resulting in a significant decrease in bonding strength and dynamic stability. The water permeability coefficient is greatly increased due to the increase in the porosity of the bonding layer.

[0128] In Comparative Example 2, the curing agent was not embedded into microcapsules, and the polyetheramine and isophorone diamine reacted with the epoxy resin in advance. As a result, crosslinking was out of control during warm mix construction, resulting in local over-curing and cracking of the bonding layer, insufficient bonding strength in local uncured layers, failure of the interlayer synergistic effect, and significantly reduced performance compared to the examples.

[0129] Comparative Example 3 uses unmodified sepiolite, which is not calcined and lacks silane coupling agent treatment. The fiber aspect ratio is small, the surface hydroxyl groups are agglomerated, the dispersion in asphalt is poor and it cannot effectively pierce the vermiculite pores, making it difficult to construct the anchor chain skeleton. The interface chemical bonding points are sharply reduced, resulting in a weakened deformation resistance of the mixture and a significant deterioration of the interlayer bonding and water-tightness properties.

[0130] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A high-performance warm-mix high-modulus water-tight paving structure, characterized in that: The paving structure is as follows from bottom to top: concrete leveling layer; Waterproof bonding layer: prepared by mixing epoxy resin main agent, microencapsulated amine curing agent, functional diluent and filler in a mass ratio of 50-60:25-35:5-8:12-18, wherein the filler is expanded vermiculite powder; Mixture lower layer: prepared by mixing high modulus agent, lower layer warm mix agent, asphalt, aggregate and mineral powder in a mass ratio of 0.4-0.8:0.3-1.1:5-6.5:80-85:2-5; the high modulus agent is prepared by mixing POE, modified sepiolite, interfacial compatibilizer and antioxidant in a mass ratio of 72-78:16-20:4-6:1-2; Non-stick wheel adhesive layer; Top layer of mixture.

2. The high-performance warm-mix high-modulus water-tight pavement structure according to claim 1, characterized in that: The main agent is prepared by compounding hydrogenated bisphenol A epoxy resin with an epoxy value of 0.38-0.45eq / 100g and o-cresol-formaldehyde epoxy resin with a softening point of 85-95°C in a mass ratio of 6-7:3-4.

3. The high-performance warm-mix high-modulus water-tight pavement structure according to claim 1, characterized in that: The expansion multiple of the expanded vermiculite powder is ≥15 times, and the particle size is 50-100 μm.

4. The high-performance warm-mix high-modulus water-tight pavement structure according to claim 1, characterized in that: The core material of the microencapsulated amine curing agent is composed of polyetheramine and isophorone diamine in a mass ratio of 4:1-3, and the capsule wall is embedded with ethyl cellulose.

5. The high-performance warm-mix high-modulus water-tight pavement structure according to claim 4, characterized in that: The preparation method of the curing agent comprises: Mixing polyetheramine and isophorone diamine, stirring at 60-70° C. until the mixture is homogeneous, to obtain a core material; Dissolve ethyl cellulose in a mixed solvent of acetone and ethyl acetate to prepare a wall material solution with a concentration of 15-20 wt%; The core material and wall material solutions are mixed in a mass ratio of 1:0.8-1.2, and shear emulsified to form an emulsion; Deionized water is slowly added dropwise to the emulsion to obtain a suspension, and the suspension is spray-dried to obtain the curing agent.

6. The high-performance warm-mix high-modulus water-tight pavement structure according to claim 1, characterized in that: The preparation method of the modified sepiolite comprises: The fibrous sepiolite is calcined at 450℃±10℃, cooled and then air-pulverized to a particle size of D50 ≤10μm; Mix the silane coupling agent with anhydrous ethanol, add acetic acid-water solution dropwise, and hydrolyze under magnetic stirring at 50°C ± 2°C to obtain a hydrolyzate; The crushed sepiolite is added into the hydrolyzate and transferred to a high pressure condition for reaction; The reaction product was filtered, and then pre-dried at 80° C., vacuum-dried at 120° C., and heat-treated at 180° C. to obtain modified sepiolite.

7. The high-performance warm mix high modulus water-tight pavement structure according to claim 1, characterized in that: The non-stick wheel adhesive layer includes cationic emulsified asphalt and stone chips. The emulsifier of the cationic emulsified asphalt is compounded by alkylbenzene sulfonate and fatty amine polyoxyethylene ether in a mass ratio of 2:1-1.

2.

8. The high-performance warm-mix high-modulus water-tight pavement structure according to claim 1, characterized in that: The upper layer of the mixture is prepared by mixing a flame retardant, an upper layer warm mix agent, modified asphalt, aggregate and activated alumina ore powder in a mass ratio of 1-2:2-4:4-6.5:84-90:5-10; The modified asphalt is based on road petroleum asphalt and is mixed with 1.5-2.5wt% of single-walled carbon nanotubes; The upper layer warm mixing agent is a compound system formed by a non-ionic surfactant containing a phosphorus oxygen group and a quaternary ammonium salt in a mass ratio of 4-6:1-4.

9. The high-performance warm-mix high-modulus water-tight pavement structure according to claim 1, characterized in that: The thickness of the concrete leveling layer is 50-100 mm; the thickness of the waterproof bonding layer is 0.5-0.7 mm; the thickness of the lower layer of the mixture is 80-100 mm; the thickness of the non-stick wheel bonding layer is 0.4-0.8 mm; and the thickness of the upper layer of the mixture is 25-35 mm.

10. A method for preparing a high-performance warm-mix high-modulus water-tight pavement structure, characterized in that: include: Concrete leveling layer: Use formwork to support 50-100mm thick concrete, vibrate and compact it, then cover and maintain it, and roughen it to a roughness of less than 1mm; Waterproof bonding layer: Mix the components according to the mass ratio, apply on the concrete leveling layer, and let it stand at room temperature to solidify; Lower layer of mixture: heat the aggregate and asphalt in sequence, add high modulus agent and lower layer warm mix agent and mix to obtain the mixture, spread and compact on the waterproof bonding layer to obtain the lower layer of mixture; Non-stick wheel bonding layer: Spray cationic emulsified asphalt evenly on the surface of the lower layer of the mixture, and then spread stone chips; Upper layer of mixture: After mixing the flame retardant, upper warm mix agent, modified asphalt, aggregate and activated alumina ore powder, spread it on the surface of the non-stick wheel bonding layer at a speed of 2~3m / min, and perform static pressing, kneading and final pressing in sequence.

Images