Ultra-thin overlay mixture based on full milling material and preparation method of ultra-thin overlay mixture

Abstract

The invention discloses an ultrathin overlay mixture based on a full milling material and a preparation method of the ultrathin overlay mixture, and belongs to the technical field of highway engineering construction materials, the ultrathin overlay mixture comprises the following components in parts by weight: 55-70 parts of super-tough cold recycled emulsified asphalt, 30-45 parts of multi-scale hybrid reinforced recycled aggregate and 0.5-1.5 parts of a modified toughening agent. Through the microscopic and macroscopic multi-scale synergistic effect of the super-tough recycled emulsified asphalt, the multi-scale hybrid reinforced recycled aggregate and the modified fiber, 100% recycling of solid waste materials is achieved, the performance of the recycled materials is greatly improved, and the problem that surface layer milling materials can only be applied to low-quality utilization of middle and lower surface layers in the past is solved.

Description

Technical Field

[0001] This invention relates to the field of road construction materials technology, specifically to an ultra-thin overlay mixture based on fully milled material and its preparation method. Background Technology

[0002] Traditional hot-mix thin-layer pavement relies on mixing plants and traditional paving machine fleets, requires high-quality wear-resistant aggregates, and has a long construction chain and high construction costs. Guided by the dual demands of road waste material reuse and green construction, there is a need for a green maintenance technology that does not require a hot-mix plant and can be applied on-site at ambient temperature. This technology aims to solve the problem of "high cost and low efficiency" in solid waste material utilization, while reducing the construction cost of ultra-thin overlays and ensuring good road performance.

[0003] Current cold recycling technologies use traditional SBS to modify asphalt, restoring asphalt properties by adding lightweight components. The recycled aggregates are simply screened and washed, and fibers are added to improve the low-temperature toughness of the mixture.

[0004] However, existing technical solutions still have some shortcomings. Traditional SBS modification can improve the performance of modified asphalt to some extent. Although the addition of new lightweight components can restore the performance of old asphalt to some extent, the effect is limited and it cannot achieve full integration with old asphalt. Simple treatment of recycled aggregates cannot completely eliminate the fine aggregate residues on the aggregates, making the interface between asphalt and aggregates a weak point in the mixture and reducing the durability of recycled mixtures. Fibers are usually non-polar materials with extremely low surface energy, making it difficult to form a good interfacial bond with asphalt materials. They are prone to debonding and separation, and their dispersibility in asphalt mixtures is limited, thus limiting their toughening effect on the mixture.

[0005] Therefore, developing an ultra-thin overlay based on fully milled material is of practical significance for the promotion and application of ultra-thin overlay technology. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide an ultra-thin overlay mixture based on fully milled material and its preparation method, thereby solving the problems of limited performance recovery of old asphalt, weak interfacial bonding, and low utilization rate in existing technologies.

[0007] To achieve the above objectives, the present invention provides the following technical solution: an ultra-thin overlay mixture based on fully milled material, comprising the following components by weight: 55-70 parts of ultra-tough cold recycled emulsified asphalt, 30-45 parts of multi-scale hybrid reinforced recycled aggregate, and 0.5-1.5 parts of modified toughening agent.

[0008] Furthermore, the super-tough cold recycled emulsified asphalt comprises the following raw materials in parts by weight: 50-60 parts of 70# road petroleum asphalt, 40-50 parts of water, 0.8-1.2 parts of compound emulsifier, 1.5-1.8 parts of reactive polymer, and 1-1.5 parts of dodecylbenzenesulfonic acid dispersant.

[0009] Furthermore, the method for preparing ultra-tough cold recycled emulsified asphalt specifically includes the following steps:

[0010] Step a: Preparation of the reactive polymer: 10 parts of SBS modifier were placed in 100 parts of cyclohexane, heated to 70°C and stirred until the SBS was completely dissolved. Then, 3 parts of 1,4-butanediol diglycidyl ether, 1 part of diphenylmethane diisocyanate, and 0.1 parts of benzyldimethylamine catalyst were added, and the reaction was carried out at 70°C for 30 minutes. After the reaction was completed, the polymer was obtained by precipitation and washing with anhydrous ethanol.

[0011] Step b: Preparation of super-tough modified asphalt: Heat 70# road petroleum asphalt to 160~170℃, add the reactive polymer obtained in step a, and shear at high speed for 30min, with a shear rate of 5000~8000r / min.

[0012] Step c: Preparation of ultra-tough cold recycled emulsified asphalt: Add the compound emulsifier to water at 60~70℃ and stir at 100rpm for 10min to prepare a soap solution; add the prepared soap solution and the ultra-tough modified asphalt from step b to a colloid mill in sequence and shear for 10min; then add dodecylbenzene sulfonic acid dispersant and mix evenly to obtain ultra-tough cold recycled emulsified asphalt.

[0013] Furthermore, the compound emulsifier includes 0.5 parts of dodecyl glucoside; 1 part of polyoxyethylene sorbitan fatty acid ester; and 1 part of monooleic acid dehydrated sorbitan ester.

[0014] Furthermore, the multi-scale hybrid reinforced recycled aggregate specifically includes the following steps:

[0015] Step ① Preparation of aminated nanofiller: Weigh 5 parts by weight of nano-calcium carbonate and 5 parts by weight of nano-cerium oxide, add them to 200 parts by weight of anhydrous ethanol, and ultrasonically disperse them at 200W power for 30 min. Then add 30 parts by weight of 3-aminopropyltriethoxysilane, react for 3 h, cool to room temperature, filter, and dry to obtain a mixture of aminated nano-calcium carbonate and nano-cerium oxide.

[0016] Step ② Preparation of multi-scale hybrid reinforced recycled aggregate: Weigh 10 parts sodium silicate and 10 parts of the mixture from step ① by weight, add 100 parts water and mix evenly. Mix the mixed solution with the recycled material at a weight ratio of 30:1000 and dry for 24 hours to obtain multi-scale hybrid reinforced recycled aggregate.

[0017] A method for preparing an ultra-thin overlay compound based on milled material, characterized in that the modified toughening agent is modified polyester fiber, and the specific preparation method is as follows: 0.2 parts by weight of tris(hydroxymethyl)aminomethane are added to 100 parts of distilled water, 1 part of catechol is added and stirred evenly, the pH is adjusted to 8.5 by hydrochloric acid, polyester fiber is added, and the mixture is shaken for 24 hours. The fiber is then removed, washed with distilled water, and dried to obtain modified polyester fiber.

[0018] This invention also provides a method for preparing an ultrathin overlay mixture based on fully milled material, characterized in that the method includes the following steps:

[0019] Step 1) The recycled old asphalt pavement material is crushed and screened, and the single-grain milled material with a diameter of 5-10 mm after screening is selected for multi-scale hybrid reinforcement treatment.

[0020] Step 2) Add the ultra-tough cold recycled emulsified asphalt, multi-scale hybrid reinforced recycled aggregate, and modified toughening agent to the corresponding emulsion tank, aggregate bin, and fiber additive box of the slurry seal vehicle, respectively.

[0021] Step 3) Control the various materials to be transported into the mixer in proportion by the slurry seal vehicle. After mixing for 60 seconds, the mixture is transported into the paving trough to complete the paving.

[0022] Step 4) After paving, cure for 1-2 hours and compact with a rubber-tired roller at least twice to form an ultra-thin overlay of 0.8cm-2.5cm.

[0023] By adopting the above technical solutions, the present invention has the following characteristics:

[0024] 1) Introducing epoxy and isocyanate dual active groups into the SBS modifier can rapidly react with aged SBS in old asphalt, reconstructing the molecular structure of aged SBS. The newly constructed molecular structure, due to the addition of the two groups, combines rigidity and flexibility, thereby significantly improving the overall performance of old asphalt. At the same time, the introduced dodecylbenzene sulfonic acid dispersant can cause the asphalt matrix association structure to dissociate, accelerate the fusion of new and old asphalt, and thus promote the molecular reconstruction of aged polymers in old asphalt by the above-mentioned active groups.

[0025] 2) The introduction of aminated nanofillers into multi-scale hybrid recycled aggregates improves aggregate performance and eliminates potential defects in the mixture by filling the microscopic voids on the surface of the recycled aggregates with the nanofillers themselves. Simultaneously, the high specific surface area of ​​the nanofillers effectively adsorbs lightweight components in the virgin asphalt, promoting the fusion of the virgin asphalt with the old asphalt on the aggregate surface. Furthermore, the amino groups on the surface of the aminated nanofillers react with SBS containing active groups to form a cross-linked network structure with nano-cerium oxide as the framework and SBS as the matrix. These multiple effects result in a stronger interfacial bond between the recycled aggregates and asphalt.

[0026] 3) The modified fiber has increased surface roughness and introduced a certain amount of active groups, which improves the reactivity between the fiber and the asphalt matrix. This makes the fiber more evenly dispersed in the asphalt mixture and the fiber-asphalt interface has higher adhesion, resulting in a stronger toughening effect for the mixture.

[0027] 4) Through the synergistic effect of ultra-tough recycled emulsified asphalt, multi-scale hybrid reinforced recycled aggregate and modified fiber at the micro and macro scales, 100% reuse of solid waste materials is achieved, significantly improving the performance of recycled materials and solving the problem of low-quality utilization of surface milling materials that could only be applied to the middle and lower layers in the past. Detailed Implementation

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] The raw materials and reagents used in the following examples are all commercially available products.

[0030] Example 1:

[0031] An ultra-thin overlay mixture based on fully milled material and its preparation method are characterized by comprising the following components by weight: 70 parts of ultra-tough cold recycled emulsified asphalt, 45 parts of multi-scale hybrid reinforced recycled aggregate, and 1.5 parts of modified toughening agent.

[0032] The super-tough cold recycled emulsified asphalt comprises the following raw materials in parts by weight: 60 parts of 70# road petroleum asphalt, 40 parts of water, 1.2 parts of compound emulsifier, 1.8 parts of reactive polymer, and 1.5 parts of dodecylbenzenesulfonic acid dispersant.

[0033] The preparation method of super-tough cold recycled emulsified asphalt is as follows:

[0034] a. Preparation of the reactive polymer: 10 parts of SBS modifier were placed in 100 parts of cyclohexane, heated to 70℃ and stirred until the SBS was completely dissolved. 3 parts of 1,4-butanediol diglycidyl ether and 1 part of diphenylmethane diisocyanate, along with 0.1 parts of benzyldimethylamine catalyst, were added, and the reaction was carried out at 70℃ for 30 min. After the reaction, the polymer was obtained by precipitation and washing with anhydrous ethanol.

[0035] b. Preparation of super-tough modified asphalt: Heat 70# road petroleum asphalt to 170℃, add the reactive polymer obtained in step a, and shear at high speed for 30 minutes at a shear rate of 8000 r / min.

[0036] c. Preparation of super-tough cold recycled emulsified asphalt: The compound emulsifier (where the ratio of dodecyl glucoside: polyoxyethylene sorbitan fatty acid ester: monooleic acid dehydrated sorbitan ester is 0.5:1:1) is added to water at 70°C and stirred at 100 rpm for 10 min to prepare a soap solution; the prepared soap solution and the super-tough modified asphalt from step b are added to a colloid mill in sequence and sheared for 10 min; then dodecylbenzene sulfonic acid dispersant is added and mixed evenly to obtain super-tough cold recycled emulsified asphalt.

[0037] The preparation method of multi-scale hybrid reinforced recycled aggregate is as follows:

[0038] ① Preparation of aminated nanofillers: Weigh 5 parts by weight of nano-calcium carbonate and 5 parts by weight of nano-cerium oxide, add them to 200 parts by weight of anhydrous ethanol, and ultrasonically disperse them for 30 min at 200 W power. Then add 30 parts by weight of 3-aminopropyltriethoxysilane, react for 3 h, cool to room temperature, filter, and dry to obtain a mixture of aminated nano-calcium carbonate and nano-cerium oxide.

[0039] ② Preparation of multi-scale hybrid reinforced recycled aggregate: Weigh 10 parts sodium silicate and 10 parts of the mixture in step ① by weight, add 100 parts water and mix evenly. Mix the mixed solution with the recycled material at a weight ratio of 30:1000 and dry for 24 hours to obtain multi-scale hybrid reinforced recycled aggregate.

[0040] The modified toughening agent is a modified polyester fiber. The specific preparation method is as follows: Weigh 0.2 parts of tris(hydroxymethyl)aminomethane and add it to 100 parts of distilled water. Add 1 part of catechol and stir evenly. Adjust the pH to 8.5 with hydrochloric acid. Add polyester fiber and shake for 24 hours. Take out the fiber, wash it with distilled water, and dry it to obtain the modified polyester fiber.

[0041] A method for preparing an ultrathin overlay compound based on fully milled material, characterized in that the method includes the following steps:

[0042] 1) The recycled old asphalt pavement material is crushed and screened, and the single-grain milled material with a diameter of 5-10 mm after screening is selected for multi-scale hybrid reinforcement treatment.

[0043] 2) Add the ultra-tough cold recycled emulsified asphalt, multi-scale hybrid reinforced recycled aggregate, and modified toughening agent to the corresponding emulsion tank, aggregate bin, and fiber additive box of the slurry seal vehicle, respectively.

[0044] 3) The various materials are transported into the mixer in proportion by the slurry seal vehicle. After mixing for 60 seconds, the mixture is transported into the paving trough to complete the paving.

[0045] 4) After paving, allow it to cure for 1-2 hours, then compact it with a rubber-tired roller at least twice to form an ultra-thin overlay of 0.8-2.5cm.

[0046] Example 2:

[0047] An ultra-thin overlay mixture based on fully milled material and its preparation method are characterized by comprising the following components by weight: 55 parts of ultra-tough cold recycled emulsified asphalt, 30 parts of multi-scale hybrid reinforced recycled aggregate, and 0.5 parts of modified toughening agent.

[0048] The super-tough cold recycled emulsified asphalt comprises the following raw materials in parts by weight: 50 parts of 70# road petroleum asphalt, 50 parts of water, 0.8 parts of compound emulsifier, 1.5 parts of reactive polymer, and 1 part of dodecylbenzenesulfonic acid dispersant.

[0049] The preparation method of super-tough cold recycled emulsified asphalt is as follows:

[0050] a. Preparation of the reactive polymer: 10 parts of SBS modifier were placed in 100 parts of cyclohexane, heated to 70℃ and stirred until the SBS was completely dissolved. 3 parts of 1,4-butanediol diglycidyl ether and 1 part of diphenylmethane diisocyanate, along with 0.1 parts of benzyldimethylamine catalyst, were added, and the reaction was carried out at 70℃ for 30 min. After the reaction, the polymer was obtained by precipitation and washing with anhydrous ethanol.

[0051] b. Preparation of super-tough modified asphalt: Heat 70# road petroleum asphalt to 160℃, add the reactive polymer obtained in step a, and shear at high speed for 30 minutes at a shear rate of 5000 r / min.

[0052] c. Preparation of super-tough cold recycled emulsified asphalt: The compound emulsifier (where the ratio of dodecyl glucoside: polyoxyethylene sorbitan fatty acid ester: monooleic acid dehydrated sorbitol ester is 0.5:1:1) is added to water at 60°C and stirred at 100 rpm for 10 min to prepare a soap solution; the prepared soap solution and the super-tough modified asphalt in step b are added to a colloid mill in sequence and sheared for 10 min; then dodecylbenzene sulfonic acid dispersant is added and mixed evenly to obtain super-tough cold recycled emulsified asphalt.

[0053] The preparation method of multi-scale hybrid reinforced recycled aggregate is as follows:

[0054] ① Preparation of aminated nanofillers: Weigh 5 parts by weight of nano-calcium carbonate and 5 parts by weight of nano-cerium oxide, add them to 200 parts by weight of anhydrous ethanol, and ultrasonically disperse them for 30 min at 200 W power. Then add 30 parts by weight of 3-aminopropyltriethoxysilane, react for 3 h, cool to room temperature, filter, and dry to obtain a mixture of aminated nano-calcium carbonate and nano-cerium oxide.

[0055] ② Preparation of multi-scale hybrid reinforced recycled aggregate: Weigh 10 parts sodium silicate and 10 parts of the mixture in step ① by weight, add 100 parts water and mix evenly. Mix the mixed solution with the recycled material at a weight ratio of 30:1000 and dry for 24 hours to obtain multi-scale hybrid reinforced recycled aggregate.

[0056] The modified toughening agent is a modified polyester fiber. The specific preparation method is as follows: Weigh 0.2 parts of tris(hydroxymethyl)aminomethane and add it to 100 parts of distilled water. Add 1 part of catechol and stir evenly. Adjust the pH to 8.5 with hydrochloric acid. Add polyester fiber and shake for 24 hours. Take out the fiber, wash it with distilled water, and dry it to obtain the modified polyester fiber.

[0057] A method for preparing an ultrathin overlay compound based on fully milled material, characterized in that the method includes the following steps:

[0058] 1) The recycled old asphalt pavement material is crushed and screened, and the single-grain milled material with a diameter of 5-10 mm after screening is selected for multi-scale hybrid reinforcement treatment.

[0059] 2) Add the ultra-tough cold recycled emulsified asphalt, multi-scale hybrid reinforced recycled aggregate, and modified toughening agent to the corresponding emulsion tank, aggregate bin, and fiber additive box of the slurry seal vehicle, respectively.

[0060] 3) The various materials are transported into the mixer in proportion by the slurry seal vehicle. After mixing for 60 seconds, the mixture is transported into the paving trough to complete the paving.

[0061] 4) After paving, allow it to cure for 1-2 hours, then compact it with a rubber-tired roller at least twice to form an ultra-thin overlay of 0.8cm-2.5cm.

[0062] Example 3:

[0063] An ultra-thin overlay mixture based on fully milled material and its preparation method are characterized by comprising the following components by weight: 62 parts of ultra-tough cold recycled emulsified asphalt, 37 parts of multi-scale hybrid reinforced recycled aggregate, and 1 part of modified toughening agent.

[0064] The super-tough cold recycled emulsified asphalt comprises the following raw materials in parts by weight: 55 parts of 70# road petroleum asphalt, 45 parts of water, 1 part of compound emulsifier, 1.65 parts of reactive polymer, and 1.25 parts of dodecylbenzenesulfonic acid dispersant.

[0065] The preparation method of super-tough cold recycled emulsified asphalt is as follows:

[0066] a. Preparation of the reactive polymer: 10 parts of SBS modifier were placed in 100 parts of cyclohexane, heated to 70℃ and stirred until the SBS was completely dissolved. 3 parts of 1,4-butanediol diglycidyl ether and 1 part of diphenylmethane diisocyanate, along with 0.1 parts of benzyldimethylamine catalyst, were added, and the reaction was carried out at 70℃ for 30 min. After the reaction, the polymer was obtained by precipitation and washing with anhydrous ethanol.

[0067] b. Preparation of super-tough modified asphalt: Heat 70# road petroleum asphalt to 165℃, add the reactive polymer obtained in step a, and shear at high speed for 30 min at a shear rate of 6500 r / min.

[0068] c. Preparation of super-tough cold recycled emulsified asphalt: The compound emulsifier (where the ratio of dodecyl glucoside: polyoxyethylene sorbitan fatty acid ester: monooleic acid dehydrated sorbitan ester is 0.5:1:1) is added to water at 65°C and stirred at 100 rpm for 10 min to prepare a soap solution; the prepared soap solution and the super-tough modified asphalt from step b are added to a colloid mill in sequence and sheared for 10 min; then dodecylbenzene sulfonic acid dispersant is added and mixed evenly to obtain super-tough cold recycled emulsified asphalt.

[0069] The preparation method of multi-scale hybrid reinforced recycled aggregate is as follows:

[0070] ① Preparation of aminated nanofillers: Weigh 5 parts by weight of nano-calcium carbonate and 5 parts by weight of nano-cerium oxide, add them to 200 parts by weight of anhydrous ethanol, and ultrasonically disperse them for 30 min at 200 W power. Then add 30 parts by weight of 3-aminopropyltriethoxysilane, react for 3 h, cool to room temperature, filter, and dry to obtain a mixture of aminated nano-calcium carbonate and nano-cerium oxide.

[0071] ② Preparation of multi-scale hybrid reinforced recycled aggregate: Weigh 10 parts sodium silicate and 10 parts of the mixture in step ① by weight, add 100 parts water and mix evenly. Mix the mixed solution with the recycled material at a weight ratio of 30:1000 and dry for 24 hours to obtain multi-scale hybrid reinforced recycled aggregate.

[0072] The modified toughening agent is a modified polyester fiber. The specific preparation method is as follows: Weigh 0.2 parts of tris(hydroxymethyl)aminomethane and add it to 100 parts of distilled water. Add 1 part of catechol and stir evenly. Adjust the pH to 8.5 with hydrochloric acid. Add polyester fiber and shake for 24 hours. Take out the fiber, wash it with distilled water, and dry it to obtain the modified polyester fiber.

[0073] A method for preparing an ultrathin overlay compound based on fully milled material, characterized in that the method includes the following steps:

[0074] 1) The recycled old asphalt pavement material is crushed and screened, and the single-grain milled material with a diameter of 5-10 mm after screening is selected for multi-scale hybrid reinforcement treatment.

[0075] 2) Add the ultra-tough cold recycled emulsified asphalt, multi-scale hybrid reinforced recycled aggregate, and modified toughening agent to the corresponding emulsion tank, aggregate bin, and fiber additive box of the slurry seal vehicle, respectively.

[0076] 3) The various materials are transported into the mixer in proportion by the slurry seal vehicle. After mixing for 60 seconds, the mixture is transported into the paving trough to complete the paving.

[0077] 4) After paving, allow it to cure for 1-2 hours, then compact it with a rubber-tired roller at least twice to form an ultra-thin overlay of 0.8cm-2.5cm.

[0078] Comparative Example 1:

[0079] The difference from Example 1 is that the polymer used for asphalt modification is SBS modifier, and no active groups are added.

[0080] Comparative Example 2:

[0081] The difference from Example 1 is that the recycled aggregate was only crushed and screened, without undergoing multi-scale hybrid reinforcement.

[0082] Comparative Example 3:

[0083] The difference from Example 1 is that the added toughening agent is ordinary polyester fiber, which has not been grafted.

[0084] The performance of the ultra-thin overlay mixture based on fully milled material prepared in Examples 1-3 of the present invention and the mixture prepared in Comparative Examples 1-3 were tested. The experimental results are shown in Table 1 below.

[0085] Table 1 Performance test results of Examples 1-3 and Comparative Examples 1-3

[0086] Example Marshall stability / kN Freeze-thaw splitting strength ratio / % Bond strength between asphalt and recycled materials / MPa Maximum bending tensile strain / μm Example 1 16.42 96.8 2.44 3566 Example 2 15.47 91.7 2.18 3196 Example 3 16.14 94.2 2.32 3325 Comparative Example 1 13.42 88.6 1.86 2864 Comparative Example 2 11.49 83.8 1.43 2755 Comparative Example 3 12.96 90.4 2.04 3029

[0087] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An ultra-thin overlay compound based on fully milled material, characterized in that: It includes the following components by weight: 55-70 parts of ultra-tough cold recycled emulsified asphalt, 30-45 parts of multi-scale hybrid reinforced recycled aggregate, and 0.5-1.5 parts of modified toughening agent.

2. The ultra-thin overlay mixture based on fully milled material according to claim 1, characterized in that: The super-tough cold recycled emulsified asphalt comprises the following raw materials in parts by weight: 50-60 parts of 70# road petroleum asphalt, 40-50 parts of water, 0.8-1.2 parts of compound emulsifier, 1.5-1.8 parts of reactive polymer, and 1-1.5 parts of dodecylbenzenesulfonic acid dispersant.

3. The ultra-thin overlay mixture based on fully milled material according to claim 1, characterized in that: The method for preparing ultra-tough cold recycled emulsified asphalt specifically includes the following steps: Step a: Preparation of the reactive polymer: 10 parts of SBS modifier were placed in 100 parts of cyclohexane, heated to 70°C and stirred until the SBS was completely dissolved. 3 parts of 1,4-butanediol diglycidyl ether and 1 part of diphenylmethane diisocyanate, and 0.1 parts of benzyl dimethylamine catalyst were added. The reaction was carried out at 70°C for 30 min. After the reaction was completed, the polymer was obtained by precipitation and washing with anhydrous ethanol. Step b: Preparation of super-tough modified asphalt: Heat 70# road petroleum asphalt to 160~170℃, add the reactive polymer obtained in step a, and shear at high speed for 30min, with a shear rate of 5000~8000r / min; Step c: Preparation of super-tough cold recycled emulsified asphalt: Add the compound emulsifier to water at 60~70℃ and stir at 100rpm for 10min to prepare a soap solution; add the prepared soap solution and the super-tough modified asphalt from step b to a colloid mill in sequence, and shear for 10min; then add dodecylbenzenesulfonic acid dispersant and mix evenly to obtain super-tough cold recycled emulsified asphalt.

4. The ultra-thin overlay mixture based on fully milled material according to claim 2, characterized in that: The compound emulsifier comprises 0.5 parts of dodecyl glucoside; 1 part of polyoxyethylene sorbitan fatty acid ester; and 1 part of monooleic acid dehydrated sorbitan ester.

5. The ultra-thin overlay mixture based on fully milled material according to claim 1, characterized in that, The multi-scale hybrid reinforced recycled aggregate specifically includes the following steps: Step ① Preparation of aminated nanofiller: Weigh 5 parts by weight of nano-calcium carbonate and 5 parts by weight of nano-cerium oxide, add them to 200 parts by weight of anhydrous ethanol, and ultrasonically disperse them for 30 min at 200 W power. Then add 30 parts by weight of 3-aminopropyltriethoxysilane, react for 3 h, cool to room temperature, filter, and dry to obtain a mixture of aminated nano-calcium carbonate and nano-cerium oxide. Step ② Preparation of multi-scale hybrid reinforced recycled aggregate: Weigh 10 parts sodium silicate and 10 parts of the mixture from step ① by weight, add 100 parts water and mix evenly. Mix the mixed solution with the recycled material at a weight ratio of 30:1000 and dry for 24 hours to obtain multi-scale hybrid reinforced recycled aggregate.

6. A method for preparing an ultra-thin overlay mixture based on fully milled material, characterized in that, The modified toughening agent is a modified polyester fiber. The specific preparation method is as follows: 0.2 parts by weight of tris(hydroxymethyl)aminomethane are added to 100 parts of distilled water, 1 part of catechol is added and stirred evenly, the pH is adjusted to 8.5 by hydrochloric acid, polyester fiber is added, and the mixture is shaken for 24 hours. The fiber is then removed, washed with distilled water, and dried to obtain the modified polyester fiber.

7. A method for preparing an ultrathin overlay mixture based on fully milled material, characterized in that, The method includes the following steps: Step 1) The recycled asphalt pavement material is crushed and screened, and the single-grain milled material with a diameter of 5-10 mm after screening is selected for multi-scale hybrid reinforcement treatment. Step 2) Add the ultra-tough cold recycled emulsified asphalt, multi-scale hybrid reinforced recycled aggregate, and modified toughening agent to the corresponding emulsion tank, aggregate bin, and fiber additive box of the slurry seal vehicle, respectively. Step 3) Control the various materials to be transported into the mixer in proportion by the slurry seal vehicle, mix for 60 seconds and then transport the mixture into the paving trough to complete the paving. Step 4) After paving, cure for 1-2 hours and compact with a rubber-tired roller at least twice to form an ultra-thin overlay of 0.8cm-2.5cm.