High-viscosity activated rubber powder grafted functionalized block copolymer composite modifier and preparation thereof, composite modified asphalt and preparation and application thereof

Abstract

The invention discloses a high-viscosity activated rubber powder grafted functionalized block copolymer composite modifier and preparation thereof, composite modified asphalt and preparation and application thereof, and belongs to the technical field of modified asphalt. The composite modifier disclosed by the invention is formed by grafting catechol / polyamine modified aminated rubber powder and an epoxidized block copolymer. A catechol / polyamine group and an amino group are subjected to a condensation reaction to jointly modify the surface of the rubber powder, so that the surface of the rubber powder has rich functional groups and active sites, the rubber powder and an epoxidized block copolymer are subjected to a chemical crosslinking reaction in the later period, and the effect of enhancing the full performance of asphalt by the composite modifier is achieved; the problems that the composite modifier and the modified asphalt are prone to agglomeration, poor in compatibility and the like are solved. A self-healing mixture prepared from the composite modified asphalt and a self-healing material together has synergistic effects of the composite modified asphalt and the self-healing material, so that the pavement performance and the use quality are effectively improved, the service life of a road is prolonged, the energy loss is reduced, and the composite modified asphalt has application value in the field of roads.

Description

Technical Field

[0001] The invention relates to a high-viscosity activated rubber powder grafted functionalized block copolymer composite modifier and preparation thereof, composite modified asphalt and preparation and application thereof, belonging to the technical field of modified asphalt. Background Art

[0002] With the rapid development of the global economy, the number of cars has continued to increase. The large number of discarded tires has brought tremendous pressure to the environment, not only polluting the soil and groundwater, but also causing resource waste. Therefore, the recycling of waste tires is of great significance for achieving resource circulation and green environmental protection. However, how to efficiently and reasonably deal with waste tires has become a problem to be solved in today's society.

[0003] As the main raw material of rubber powder, waste tires have become the key path to produce rubber powder through recycling and reuse, which is also an active advocacy of the recycling economy of waste tires. It can not only reduce the pressure on the environment and achieve sustainable development, but also save production costs and improve economic benefits. Therefore, with the maturity of the technology of converting waste tires into rubber powder and the continuous development of application fields, rubber powder will play a huge role in the future circular economy.

[0004] Rubber powder used as a modifier in the preparation of modified asphalt can effectively improve the high temperature stability, low temperature crack resistance and fatigue resistance of asphalt. It not only effectively utilizes waste resources, prevents harmful gas emissions, reduces environmental pollution, but also has low production costs. However, since rubber powder, as a granular solid, is combined with asphalt, it has poor storage stability and is prone to phase separation, which affects the overall stability of rubber powder modified asphalt. It is necessary to use admixtures and a variety of processing techniques to reduce the occurrence of such problems.

[0005] As a road construction material with excellent performance, block copolymers have good elasticity and plasticity, which can effectively improve the compatibility between rubber powder and asphalt. They work synergistically with rubber powder under high temperature environment to form a stable three-dimensional network structure inside the asphalt, and improve the flexibility and ductility of modified asphalt under low temperature conditions. In view of the current situation, block copolymers and rubber powder are mainly mixed together to prepare composite modified asphalt. The structural difference between the two is large, and agglomeration is easy to occur inside the asphalt, thereby destroying the uniform distribution of the modifier. In actual application, stress concentration is easy to occur, which reduces the overall performance of the composite modified asphalt.

[0006] Therefore, it is of great significance to synthesize a composite modified material that has the excellent properties of block copolymers and rubber powder and good compatibility through chemical modification to reduce energy consumption and improve modification effect. Summary of the invention

[0007] Aiming at the deficiencies of the prior art, the present invention provides a high-viscosity activated rubber powder grafted functionalized block copolymer composite modifier and its preparation, a composite modified asphalt and its preparation and application. The present invention modifies rubber powder with catechol monomers and polyamine compounds, and then grafts an epoxy-functionalized block copolymer to obtain an amino-functionalized rubber powder modified with catechol / polyamine groups, which has high viscosity, waterproof and other characteristics, and solves the problems of poor storage stability between the composite modifier and the asphalt matrix and easy segregation. The obtained composite modified asphalt has excellent low-temperature crack resistance and high-temperature stability performance.

[0008] The technical solution of the present invention is as follows: A preparation method of a high-viscosity activated rubber powder grafted functionalized block copolymer composite modifier, comprising the following steps: (1) Amino-functionalized rubber powder modified with catechol / polyamine groups Add rubber powder to an alkaline solution, stir evenly and soak it, then filter, wash and dry to obtain rubber powder a; mix absolute ethanol and amino group compounds, stir, and let stand to obtain a hydrolysis solution; add rubber powder a to the hydrolysis solution, stir evenly and let stand, filter, wash and dry to obtain rubber powder b; mix catechol monomers, polyamine monomers, an initiator aqueous solution and organic solvent A, stir and react to obtain a prepolymer mixed solution; add rubber powder b and catalyst I to the prepolymer mixed solution, react, and after the reaction is completed, centrifuge and dry to obtain amino-functionalized rubber powder modified with catechol / polyamine groups; (2) Functionalized modified block copolymer Add the block copolymer to organic solvent B, stir until dissolved to obtain a mixed solution, then add an organic acid and catalyst II to the mixed solution, stir, and then dropwise add an aqueous hydrogen peroxide solution for reaction; after the reaction is completed, cool to room temperature, add absolute ethanol to the reaction solution to precipitate the reaction product by coagulation, filter and dry to obtain an epoxy-functionalized block copolymer; (3) Grafting reaction Dissolve the epoxy-functionalized block copolymer in organic solvent C, add the amino-functionalized rubber powder modified with catechol / polyamine groups and catalyst III, heat and stir for reaction; after the reaction is completed, filter and dry to obtain an amino-functionalized rubber powder modified with catechol / polyamine groups grafted with an epoxy-functionalized block copolymer composite modifier, which is a high-viscosity activated rubber powder grafted functionalized block copolymer composite modifier.

[0009] Preferably according to the present invention, in the preparation method of the composite modifier, in step (1), the raw materials are selected from the following parts by mass: 10-15 parts of rubber powder, 100-120 parts of alkaline solution, 300-500 parts of absolute ethanol, 0.1-2 parts of amino group compound, 0.5-3 parts of catechol monomer, 0.5-3 parts of polyamine monomer, 0.1-1 part of initiator aqueous solution, 100-350 parts of organic solvent A, and 0.1-1 part of catalyst I.

[0010] According to the present invention, in the preparation method of the composite modifier, the rubber powder in step (1) is an ordinary commercially available product obtained by producing and processing waste tires by the normal temperature pulverization method.

[0011] Preferably according to the present invention, in the preparation method of the composite modifier, in step (1), the mass concentration of the alkaline solution is 2-10 wt%; the alkali in the alkaline solution is selected from one or more of sodium hydroxide, potassium hydroxide, lithium hydroxide, and barium hydroxide; the amino group compound is selected from one or more of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, and bis(γ-triethoxysilylpropyl)amine; the catechol monomer is selected from one or more of catechol, 4-tert-butylcatechol, 4-methylcatechol, 3,4-dihydroxystyrene, 3,4-dihydroxybenzoic acid, 4-(2-aminoethyl)benzene-1,2-diol, and gallic acid; the polyamine monomer is selected from one or more of ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, polyethylenepolyamine, 1,3-diaminopropane, 1,4-butanediamine, and 1,5-pentanediamine; the initiator is selected from one or more of potassium persulfate, ammonium persulfate, azobisisobutyronitrile, azobisisoheptonitrile, and benzoyl peroxide, and the mass concentration of the initiator aqueous solution is 0.5-1.5 wt%; the organic solvent A is selected from one or more of methanol, ethanol, N,N-dimethylformamide, N-methylpyrrolidone, tetrahydrofuran, 1,4-dioxane, dichloromethane, and chloroform; the catalyst I is selected from one or more of triethylamine, pyridine, sodium hydroxide, aqueous ammonia solution, laccase, tyrosinase, ferric chloride, and ferric sulfate, and the mass concentration of the aqueous ammonia solution is 25-28 wt%.

[0012] Preferably according to the present invention, in the preparation method of the composite modifier, in step (1), when the rubber powder is added to the alkaline solution, the stirring rate is 600-800 r / min, the stirring time is 30-40 min, and the soaking time is 30-100 min; after soaking in the alkaline solution, it is filtered, and the obtained solid is washed 3-5 times with deionized water, and then dried at 50-60 °C for 6-8 h to obtain rubber powder a.

[0013] Preferably according to the present invention, in the preparation method of the composite modifier, in step (1), in the preparation of the hydrolysis solution, after mixing anhydrous ethanol and the amino group compound, the stirring time is 30 to 40 minutes, and the standing time is 1 to 2 hours.

[0014] Preferably according to the present invention, in the preparation method of the composite modifier, in step (1), the rate of adding the rubber powder a into the hydrolysis solution for stirring is 500 to 600 r / min, the stirring time is 30 to 40 minutes, the standing time is 1 to 2 hours, then filtering, washing the obtained solid with deionized water 2 to 3 times, and then drying at 50 to 60 °C for 6 to 8 hours to obtain the rubber powder b.

[0015] Preferably according to the present invention, in the preparation method of the composite modifier, in step (1), after mixing the catechol monomer, the polyamine monomer, the initiator aqueous solution and the organic solvent A, the conditions for the stirring reaction are as follows: the reaction temperature is 60 to 70 °C, the stirring rate is 500 to 600 r / min, and the reaction time is 3 to 4 hours.

[0016] Preferably according to the present invention, in the preparation method of the composite modifier, in step (1), when adding the rubber powder b and the catalyst I into the prepolymer mixed solution, the reaction conditions are as follows: the reaction temperature is 60 to 70 °C, the stirring rate is 600 to 800 r / min, and the reaction time is 3 to 4 hours; the conditions for centrifugation are as follows: the centrifugation speed is 5000 to 6000 r / min, and the centrifugation time is 15 to 30 minutes; the conditions for drying after centrifugation are: drying the centrifuged solid at 60 to 80 °C for 6 to 8 hours.

[0017] Preferably according to the present invention, in the preparation method of the composite modifier, in step (2), the amounts of the raw materials are selected as follows by mass parts: 8 to 10 parts of block copolymer, 80 to 100 parts of organic solvent B, 0.8 to 1.2 parts of organic acid, 0.1 to 0.2 parts of catalyst II, 3 to 5 parts of hydrogen peroxide aqueous solution, and 200 to 400 parts of anhydrous ethanol.

[0018] Preferably according to the present invention, in the preparation method of the composite modifier, in step (2), the block copolymer is selected from at least one of styrene-butadiene-styrene copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), styrene-ethylene-butene-styrene block copolymer (SEBS), styrene-ethylene-propylene-styrene block copolymer (SEPS), styrene-ethylene-propylene copolymer (SEP), and styrene-isoprene-butadiene-styrene copolymer (SIBS). There is no specific requirement for the molecular weight of the block copolymer. For example, the number average molecular weight commonly used in the art can be 80,000 to 500,000; the organic solvent B is selected from one or more of cyclohexane, n-hexane, dichloromethane, N,N-dimethylformamide, N,N-diethylformamide, and toluene; the organic acid is selected from one or more of formic acid, m-chloroperbenzoic acid, perbenzoic acid, and peracetic acid; the catalyst II is selected from one or more of polyethylene glycol, dimethyl ether of polyethylene glycol, polypropylene glycol, poloxamer, monomethyl ether of polyethylene glycol, and block polyether of polypropylene glycol. The number average molecular weight of the catalyst II is 200 to 35,000; the mass concentration of the hydrogen peroxide aqueous solution is 20 to 30 wt%.

[0019] Preferably according to the present invention, in the preparation method of the composite modifier, in step (2), when the block copolymer is added to the organic solvent B and stirred, the conditions are: the temperature is 60 to 80 °C; when the mixed solution is added with the organic acid and the catalyst II and stirred, the conditions are: the temperature is 60 to 80 °C, and the time is 0.1 to 1 h; when the hydrogen peroxide aqueous solution is added dropwise and reacted, the conditions are: the reaction temperature is 60 to 80 °C, and the reaction time is 3 to 4 h; the drying is carried out at 50 to 60 °C for 6 to 8 h.

[0020] Preferably according to the present invention, in the preparation method of the composite modifier, in step (3), the raw materials are selected in the following mass parts: 8 to 10 parts of epoxy-functionalized block copolymer, 70 to 90 parts of organic solvent C, 20 to 25 parts of amino-functionalized rubber powder modified with catechol / polyamine groups, and 0.3 to 0.6 parts of catalyst III.

[0021] Preferably according to the present invention, in the preparation method of the composite modifier, in step (3), the organic solvent C is selected from one of cyclohexane, n-hexane, dichloromethane, N,N-dimethylformamide, N,N-diethylformamide, and toluene; the catalyst III is selected from one or more of polyethylene glycol, dimethyl ether of polyethylene glycol, polypropylene glycol, tetrabutylammonium bromide, triethylbenzylammonium chloride, and poloxamer; the number average molecular weight of the polyethylene glycol, dimethyl ether of polyethylene glycol, polypropylene glycol, or poloxamer is 200 to 35,000.

[0022] Preferably according to the present invention, in the preparation method of the composite modifier, in the step (3), the conditions for the heating and stirring reaction are: the reaction temperature is 60 - 80 °C, the stirring rate is 300 - 600 r / min, and the reaction time is 3 - 4 h; the drying conditions are drying at 50 - 60 °C for 6 - 8 h.

[0023] The present invention provides a high-viscosity activated rubber powder grafted functionalized block copolymer composite modifier, which is prepared by the above preparation method.

[0024] The present invention provides a preparation method of composite modified asphalt, including the following steps: Heat the base asphalt to a flowing state, add the high-viscosity activated rubber powder grafted functionalized block copolymer composite modifier, carry out high-speed stirring, then add a compatibilizer, carry out high-speed shearing, then add a stabilizer, carry out low-speed stirring, and finally carry out high-temperature development to obtain the high-viscosity activated rubber powder grafted functionalized block copolymer composite modified asphalt.

[0025] Preferably according to the present invention, in the preparation method of the composite modified asphalt, the respective raw materials are selected from the following mass parts: 100 - 120 parts of base asphalt, 25 - 33 parts of the high-viscosity activated rubber powder grafted functionalized block copolymer composite modifier, 3 - 6 parts of compatibilizer, and 0.3 - 0.6 parts of stabilizer.

[0026] Preferably according to the present invention, in the preparation method of the composite modified asphalt, the base asphalt is selected from one or more of petroleum asphalt, natural asphalt, and coal asphalt; the compatibilizer is selected from one or more of furfural extract oil, aromatic oil, rubber oil, and dibutyl phthalate; the stabilizer is selected from at least one of diethylenetriamine, triethylenetetramine, 2,6-di-tert-butyl-p-cresol, hydroquinone, magnesium oxide, magnesium carbonate, aluminum oxide, calcium oxide, calcium hydroxide, sulfur, montmorillonite, and kaolin.

[0027] Preferably according to the present invention, in the preparation method of the composite modified asphalt, the conditions for the high-speed stirring are: the stirring temperature is 170 - 180 °C, the stirring rate is 800 - 1000 r / min, and the stirring time is 30 - 40 min; the conditions for the high-speed shearing are: the shearing temperature is 180 - 190 °C, the shearing rate is 4500 - 5000 r / min, and the shearing time is 40 - 50 min; the conditions for the low-speed stirring are: the stirring temperature is 180 - 185 °C, the stirring rate is 500 - 600 r / min, and the stirring time is 30 - 40 min; the conditions for the high-temperature development are: the temperature is 180 - 185 °C, the development time is 30 - 40 min, and stirring is carried out 3 times during the high-temperature development process, stirring once every 10 - 15 min.

[0028] The present invention provides the composite modified asphalt prepared by the above preparation method.

[0029] The present invention provides an application of the above-mentioned composite modified asphalt in preparing a modified asphalt self-healing mixture for road paving.

[0030] The present invention provides a modified asphalt self-healing mixture, which is prepared by the following method: (i) Preparation of self-healing modified fiber Add the fiber into an aqueous solution of an oxidant, stir for oxidation treatment, filter, wash, and dry to obtain the oxidized fiber; add the oxidized fiber into an acidic solution for soaking, filter, wash, and dry to obtain the acid-treated fiber; add the nanomaterial and the silane coupling agent into an aqueous ethanol solution, stir to obtain a suspension solution; add the acid-treated fiber into the suspension solution, perform ultrasonic dispersion, filter, and dry to obtain the self-healing modified fiber; (ii) Preparation of the modified asphalt self-healing mixture Perform high-temperature mixing on the aggregate, add the self-healing modified fiber, and perform high-temperature mixing; then add the composite modified asphalt and perform high-temperature mixing; then add the mineral powder and perform high-temperature mixing to obtain a high-viscosity modified asphalt self-healing mixture.

[0031] Preferably according to the present invention, in the preparation of the modified asphalt self-healing mixture, in step (i), the respective raw materials are selected from the following mass parts: 10-15 parts of fiber, 80-100 parts of the aqueous solution of the oxidant, 80-120 parts of the acidic solution, 6-12 parts of the nanomaterial, 3-5 parts of the silane coupling agent, and 120-180 parts of the aqueous ethanol solution; Preferably according to the present invention, in the preparation of the modified asphalt self-healing mixture, in step (i), the fibers are selected from one or more of basalt fibers, glass fibers, lignin fibers, mineral fibers, polypropylene fibers, polyester fibers, carbon fibers, and straw fibers; the oxidant is selected from one of sodium hypochlorite, hydrogen peroxide, sodium dichloroisocyanurate, potassium dichromate, and potassium permanganate. When the oxidant is sodium hypochlorite, the mass concentration of the oxidant aqueous solution is 5-10 wt%. When the oxidant is hydrogen peroxide, sodium dichloroisocyanurate, potassium dichromate, or potassium permanganate, the mass concentration of the oxidant aqueous solution is 10-20 wt%; the acidic solution is selected from one or more of hydrochloric acid solution, nitric acid solution, phosphoric acid solution, acetic acid solution, oxalic acid solution, and carbonic acid solution, and the mass concentration of the acidic solution is 3-8 wt%; the nanomaterials are selected from one or more of nano-silica, nano-titanium dioxide, nano-zinc oxide, carbon nanotubes, graphene, nano-CoO, nano-Fe3O4, and nano-γ-Fe2O3; the silane coupling agent is selected from one or more of γ-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, aminopropyltriethoxysilane, and γ-aminopropyltriethoxysilane; the mass concentration of ethanol in the ethanol aqueous solution is 70-80 wt%.

[0032] Preferably according to the present invention, in the preparation of the modified asphalt self-healing mixture, in step (i), the conditions for oxidation treatment are: the stirring time is 30-60 min, and the stirring rate is 300-500 r / min; the conditions for soaking are as follows: the soaking time is 30-60 min; the conditions for preparing the suspension solution are as follows: the stirring time is 30-40 min, and the stirring rate is 300-500 r / min; the conditions for ultrasonic dispersion are as follows: the ultrasonic dispersion time is 30-40 min; the washing is carried out 3-5 times with deionized water, and the drying is carried out at 60-80 °C for 6-8 h.

[0033] Preferably according to the present invention, in the preparation of the modified asphalt self-healing mixture, in step (ii), the raw materials are selected from the following mass parts: 100-130 parts of aggregate, 2-4 parts of self-healing modified fiber, 8-10 parts of composite modified asphalt, and 5-6 parts of mineral powder.

[0034] Preferably according to the present invention, in the preparation of the modified asphalt self-healing mixture, in step (ii), the conditions for high-temperature mixing are: the mixing temperature is 175-185 °C, and the mixing time is 80-100 s.

[0035] The technical features and beneficial effects of the present invention are as follows: 1. The present invention is based on amino-functionalized rubber powder modified with catechol / polyamine groups. According to the excellent waterproof, adhesion and strong compatibility characteristics of catechol / polyamine groups, the rubber powder has the advantages of high viscosity, waterproofness, low cost and simple synthesis process through chemical reactions, solving the problems such as poor storage stability between the composite modifier and the asphalt matrix and poor modification effect caused by easy segregation.

[0036] 2. In the present invention, the epoxy group on the surface of the block copolymer reacts with the amino group on the surface of the modified rubber powder through a ring-opening reaction to form an epoxy compound, and the carbon-carbon hydrogen bond reacts with sulfur in the rubber powder. Through cross-linking synergy, the activated rubber powder and the functionalized block copolymer form a cured product with a three-dimensional network structure, improving the bonding strength between the composites. When the composite material is mixed with the matrix asphalt, it undergoes a chemical cross-linking reaction with asphalt molecules, improving the overall compatibility of the composite modified asphalt and enhancing its low-temperature crack resistance and high-temperature stability.

[0037] 3. The present invention uses different treatment methods to activate the surfaces of the rubber powder and the block copolymer, and applies a variety of grafting processes to synergistically treat the graft polymerization reaction of the activated rubber powder and the functionalized block copolymer, making the two closely connected by chemical bonds, with excellent adhesion performance and water resistance characteristics, effectively enhancing the bonding force between the composite material and the asphalt interface, simplifying the preparation process steps, reducing resource waste and lowering production energy consumption.

[0038] 4. The composite modified asphalt self-healing mixture prepared by the present invention enhances the overall road performance of the asphalt mixture in practical applications and reduces the generation and development of pavement diseases. When the road surface generates cracks due to long-term traffic loads, the self-healing repair agent fills and repairs these fine cracks, not only restoring the use performance of the asphalt mixture and extending its service life, but also reducing the maintenance cost and frequency, being beneficial to green environmental protection and sustainable development, and having good durability and use value. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a contact angle diagram of water on different rubber powder surfaces; among them, (a) is unmodified rubber powder, (b) is amino-functionalized rubber powder modified with 4-tert-butylcatechol / hexamethylenediamine groups in Example 1, and (c) is amino-functionalized rubber powder modified with 4-tert-butylcatechol / hexamethylenediamine groups in Example 1 grafted with epoxy-functionalized styrene-ethylene-butene-styrene block copolymer; Figure 2 It is a swelling index diagram of different rubber powders; among them, (a) is unmodified rubber powder, (b) is amino-functionalized rubber powder modified with 4-tert-butylcatechol / hexamethylenediamine groups in Example 1, and (c) is amino-functionalized rubber powder modified with 4-tert-butylcatechol / hexamethylenediamine groups in Example 1 grafted with epoxy-functionalized styrene-ethylene-butene-styrene block copolymer; Figure 3 Scanning electron microscope images of different rubber powders, where (a) is unmodified rubber powder, (b) is the 4-tert-butylcatechol / hexamethylenediamine group-modified amino rubber powder in Example 1, and (c) is the 4-tert-butylcatechol / hexamethylenediamine group-modified amino rubber powder grafted with epoxy-functionalized styrene-ethylene-butene-styrene block copolymer in Example 1; Figure 4 Infrared spectra of unmodified rubber powder and the 4-tert-butylcatechol / hexamethylenediamine group-modified amino rubber powder grafted with epoxy-functionalized styrene-ethylene-butene-styrene block copolymer in Example 1; Figure 5 Storage stability test results of the composite modified asphalt prepared in Examples 1-5 and Comparative Examples 1-4; Figure 6 Fluorescence microscope images of the composite modified asphalt prepared with different modifiers, where (a) is the unmodified rubber powder composite modified asphalt prepared in Comparative Example 6, (b) is the epoxy-functionalized styrene-ethylene-butene-styrene block copolymer composite modified asphalt prepared in Comparative Example 2, and (c) is the 4-tert-butylcatechol / hexamethylenediamine group-modified amino rubber powder grafted with epoxy-functionalized styrene-ethylene-butene-styrene block copolymer composite modified asphalt prepared in Example 1; Figure 7 Complex shear modulus of the modified asphalt prepared in Examples 1-3 and Comparative Examples 1-4; Figure 8 Phase angle of the modified asphalt prepared in Examples 1-3 and Comparative Examples 1-4; Figure 9 Rutting factor of the modified asphalt prepared in Examples 1-3 and Comparative Examples 1-4; Figure 10 Creep stiffness of the modified asphalt prepared in Examples 1-3 and Comparative Examples 1-4; Figure 11 Creep rate of the modified asphalt prepared in Examples 1-3 and Comparative Examples 1-4. Detailed implementation mode

[0040] The asphalt used in the examples is the "Donghai Brand" No. 70 base asphalt produced by Sinopec, and its relevant technical indicators are shown in Table 1 below.

[0041] Table 1

[0042] In the present invention, the rubber powder is obtained by production and processing of waste tires using the normal temperature crushing method and is purchased from Shaanxi Hongrui Rubber Products Factory.

[0043] In the present invention, the furfural extract oil is produced by Shandong Furunda Chemical Co., Ltd.

[0044] In the present invention, the crumb rubber has high elasticity, flexibility and corrosion resistance, and can effectively improve the high-temperature rutting resistance, low-temperature cracking resistance and anti-aging performance of the modified asphalt. However, since the crumb rubber, as a macromolecular polymer, is prone to segregation inside the asphalt, and there are defects such as insufficient stability during the road paving stage, the catechol group can effectively improve the surface adhesion of the crumb rubber. The functionalized block copolymer can significantly enhance the low-temperature cracking resistance of the asphalt.

[0045] Other materials used in the present invention, unless otherwise stated, can be obtained through commercial channels. Other terms used in the present invention, unless otherwise specified, generally have the meanings commonly understood by those of ordinary skill in the art. The present invention will be described in further detail below with reference to specific examples and data. The following examples are only for illustrating the present invention and do not limit the scope of the present invention in any way.

[0046] Example 1 This example relates to the preparation of a composite modifier of 4-tert-butylcatechol / hexamethylenediamine group-modified amino-crumb rubber grafted with epoxy-functionalized styrene-ethylene-butene-styrene block copolymer, a composite modified asphalt, and a self-healing mixture of the modified asphalt.

[0047] 1. Composite modifier of 4-tert-butylcatechol / hexamethylenediamine group-modified amino-crumb rubber grafted with epoxy-functionalized styrene-ethylene-butene-styrene block copolymer The preparation method is as follows: (1) Preparation of 4-tert-butylcatechol / hexamethylenediamine group-modified amino-crumb rubber 12 g of rubber powder was added to 100 g of potassium hydroxide solution with a mass concentration of 5 wt%, stirred at a stirring rate of 600 r / min for 30 min, then soaked for 70 min, and then filtered. The obtained solid was washed 3 times with deionized water, and then placed in an oven at 60 °C for drying for 6 h to obtain rubber powder a; 395 g of absolute ethanol was mixed with 0.5 g of γ-aminopropyltrimethoxysilane, stirred for 30 min, and then left standing for 1 h to obtain a hydrolysis solution. Rubber powder a was added to the hydrolysis solution, stirred at a stirring rate of 600 r / min for 30 min, left standing for 1 h, the product was taken out, washed 3 times with deionized water, and placed in an oven at 60 °C for drying for 6 h to obtain rubber powder b; 1 g of 4-tert-butylcatechol, 1 g of hexamethylenediamine, and 0.2 g of potassium persulfate aqueous solution (mass concentration of 1 wt%) were added to 200 g of N,N-dimethylformamide, and stirred and reacted at 60 °C and a stirring rate of 600 r / min for 3 h to obtain a prepolymer mixed solution. Rubber powder b and 0.2 g of pyridine were added to the prepolymer mixed solution, and reacted at 60 °C and a stirring rate of 600 r / min for 4 h. After the reaction, the reaction product was centrifuged at a centrifugal speed of 5500 r / min for 20 min, the upper clear liquid was poured out, and the obtained solid was placed in an oven at 60 °C for drying for 8 h to obtain 4-tert-butylcatechol / hexamethylenediamine group-modified amino-functionalized rubber powder.

[0048] (2) Preparation of epoxy-functionalized styrene-ethylene-butene-styrene block copolymer 8 g of styrene-ethylene-butene-styrene block copolymer (SEBS, number average molecular weight 150000) was added to 80 g of cyclohexane, stirred at 80 °C until the styrene-ethylene-butene-styrene block copolymer (SEBS) was completely dissolved to obtain a mixed solution, then 0.8 g of formic acid and 0.2 g of polyethylene glycol (number average molecular weight 200) were added, the temperature was maintained at 80 °C, stirred for 1 h, 3 g of hydrogen peroxide aqueous solution (dropwise addition rate of 2 s / drop, concentration of 30 wt%) was added dropwise. After the dropwise addition was completed, the reaction was carried out at 80 °C for 3 h. After the reaction, it was naturally cooled to room temperature. 300 g of absolute ethanol was added to the obtained reaction solution to coagulate and precipitate the reaction product, filtered, and the obtained solid was placed in an oven at 60 °C for drying for 6 h to obtain epoxy-functionalized styrene-ethylene-butene-styrene block copolymer.

[0049] (3) Preparation of 4-tert-butylcatechol / hexamethylenediamine group-modified amino-functionalized rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer composite modifier 10 g of epoxy-functionalized styrene-ethylene-butene-styrene block copolymer was added to 80 g of cyclohexane, followed by the addition of 20 g of 4-tert-butylcatechol / hexamethylenediamine group-modified amino rubber powder and 0.5 g of polyethylene glycol dimethyl ether (number average molecular weight 800). The mixture was stirred at 60 °C and a stirring rate of 500 r / min for 3 h. After the reaction, it was filtered, and the obtained solid was dried in an oven at 60 °C for 6 h to obtain a 4-tert-butylcatechol / hexamethylenediamine group-modified amino rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer composite modifier.

[0050] 2. Composite modified asphalt The preparation method is as follows: 100 g of No. 70 petroleum asphalt was heated to a flowing state, and 25 g of 4-tert-butylcatechol / hexamethylenediamine group-modified amino rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer composite modifier was added. The mixture was stirred at 170 °C and a stirring rate of 800 r / min for 30 min. Then, 3 g of furfural extract oil was added, and it was sheared at 180 °C and a shearing rate of 5000 r / min for 40 min using a high-speed shearer. Next, 0.3 g of sulfur was added, and the mixture was stirred at 185 °C and a stirring rate of 500 r / min for 30 min. Finally, it was placed in an oven for high-temperature development at 180 °C for 30 min. During the high-temperature development process, stirring was carried out 3 times, with stirring every 10 min, to obtain 4-tert-butylcatechol / hexamethylenediamine group-modified amino rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer composite modified asphalt.

[0051] 3. Modified asphalt self-healing mixture The preparation method is as follows: (1) Preparation of self-healing modified fiber 10 g of basalt fiber was added to 80 g of sodium hypochlorite aqueous solution (mass concentration 10 wt%), and the mixture was stirred at a stirring rate of 300 r / min for 30 min. Then, it was filtered, washed 3 times with deionized water, and dried in an oven at 60 °C for 6 h to obtain oxidized fiber; the oxidized fiber was immersed in 80 g of hydrochloric acid solution with a mass concentration of 5 wt% for 40 min, then filtered, washed 3 times with deionized water, and dried in an oven at 60 °C for 6 h to obtain acid-treated fiber; 8 g of nano-titanium dioxide and 3 g of γ-aminopropyltriethoxysilane were added to 150 g of ethanol aqueous solution with a mass concentration of 75 wt%, and the mixture was stirred at a stirring rate of 400 r / min for 40 min to obtain a suspension solution; the acid-treated fiber was added to the suspension solution, placed in an ultrasonic disperser for ultrasonic dispersion for 40 min, filtered, and then dried in an oven at 60 °C for 6 h to obtain self-healing modified fiber.

[0052] (1) Preparation of self-healing modified asphalt mixture Mix 100 g of aggregate at high temperature, with a mixing temperature of 175 °C and a mixing time of 90 s; add 3 g of self-healing modified fiber and mix at high temperature, with a mixing temperature of 175 °C and a mixing time of 90 s; then add 8 g of 4-tert-butylcatechol / hexamethylenediamine group-modified amino rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer composite modified asphalt and mix at high temperature, with a mixing temperature of 175 °C and a mixing time of 90 s; then add 5 g of mineral powder and mix at high temperature, with a mixing temperature of 175 °C and a mixing time of 90 s to obtain 4-tert-butylcatechol / hexamethylenediamine group-modified amino rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer composite modified asphalt self-healing mixture.

[0053] Example 2 This example relates to the preparation of 4-tert-butylcatechol / hexamethylenediamine group-modified amino rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer composite modifier, composite modified asphalt and modified asphalt self-healing mixture. The preparation method is as shown in Example 1 above. The difference from Example 1 is that in the preparation step of the composite modified asphalt, the usage amount of 4-tert-butylcatechol / hexamethylenediamine group-modified amino rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer is 28 g.

[0054] Example 3 This example relates to the preparation of 4-tert-butylcatechol / hexamethylenediamine group-modified amino rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer composite modifier, composite modified asphalt and modified asphalt self-healing mixture. The preparation method is as shown in Example 1 above. The difference from Example 1 is that in the preparation step of the composite modified asphalt, the usage amount of 4-tert-butylcatechol / hexamethylenediamine group-modified amino rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer is 31 g.

[0055] Example 4 This example relates to the preparation of gallic acid / ethylenediamine group-modified amino rubber powder grafted epoxy-functionalized styrene-isoprene-styrene block copolymer composite modifier, composite modified asphalt and modified asphalt self-healing mixture.

[0056] 1. Gallic acid / ethylenediamine group-modified amino rubber powder grafted epoxy-functionalized styrene-isoprene-styrene block copolymer composite modifier The preparation method is as follows: (1) Preparation of gallic acid / ethylenediamine group-modified amino rubber powder Add 12 g of rubber powder into 100 g of potassium hydroxide solution with a mass concentration of 5 wt%, stir at a stirring rate of 600 r / min for 30 min, then soak for 70 min, then filter. Wash the obtained solid with deionized water three times, and then put it into an oven at 60 °C for drying for 6 h to obtain rubber powder a. Mix 395 g of absolute ethanol with 0.5 g of N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, stir for 30 min, and then let it stand for 1 h to obtain a hydrolysis solution. Add rubber powder a into the hydrolysis solution, stir at a stirring rate of 600 r / min for 30 min, let it stand for 1 h, take out the product, wash it with deionized water three times, and put it into an oven at 60 °C for drying for 6 h to obtain rubber powder b. Add 1 g of gallic acid, 1 g of ethylenediamine, and 0.2 g of ammonium persulfate aqueous solution (mass concentration of 1 wt%) into 200 g of N-methylpyrrolidone, and stir and react for 3 h at 60 °C and a stirring rate of 600 r / min to obtain a prepolymer mixed solution. Add rubber powder b and 0.2 g of triethylamine into the prepolymer mixed solution, and react at 60 °C and a stirring rate of 600 r / min for 4 h. After the reaction is completed, centrifuge the reaction product at a centrifugal speed of 5500 r / min for 20 min, pour out the supernatant, and put the obtained solid into an oven at 60 °C for drying for 8 h to obtain amino-functionalized rubber powder modified with gallic acid / ethylenediamine groups.

[0057] (2)Preparation of epoxy-functionalized styrene-isoprene-styrene block copolymer Add 9 g of styrene-isoprene-styrene block copolymer (SIS, number-average molecular weight 15000) into 90 g of cyclohexane, stir at 80 °C until the styrene-isoprene-styrene block copolymer (SIB) is completely dissolved to obtain a mixed solution. Then add 0.9 g of formic acid and 0.2 g of polyethylene glycol (number-average molecular weight 200), keep the temperature at 80 °C, stir for 1 h, and dropwise add 4 g of hydrogen peroxide aqueous solution (dropwise addition rate is 2 s / drop, concentration is 30 wt%). After the dropwise addition is completed, react at 80 °C for 3 h. After the reaction is completed, naturally cool to room temperature, add 300 g of absolute ethanol to the obtained reaction solution to coagulate and precipitate the reaction product, filter, and put the obtained solid into an oven at 60 °C for drying for 6 h to obtain epoxy-functionalized styrene-isoprene-styrene block copolymer.

[0058] (3)Preparation of composite modifier of amino-functionalized rubber powder modified with gallic acid / ethylenediamine groups grafted with epoxy-functionalized styrene-isoprene-styrene block copolymer 9 g of epoxy-functionalized styrene-isoprene-styrene block copolymer was added to 80 g of cyclohexane, 21 g of amino-functionalized rubber powder modified with gallic acid / ethylenediamine groups was added, and 0.5 g of polyethylene glycol dimethyl ether (number-average molecular weight 800) was added. The mixture was stirred and reacted at 60 °C and a stirring rate of 500 r / min for 3 h. After the reaction, it was filtered, and the obtained solid was dried in an oven at 60 °C for 6 h to obtain a composite modifier of amino-functionalized rubber powder modified with gallic acid / ethylenediamine groups grafted with epoxy-functionalized styrene-isoprene-styrene block copolymer.

[0059] 2. Composite modified asphalt The preparation method is as follows: 100 g of No. 70 petroleum asphalt was heated to a flowing state, 28 g of the composite modifier of amino-functionalized rubber powder modified with gallic acid / ethylenediamine groups grafted with epoxy-functionalized styrene-isoprene-styrene block copolymer was added, and it was stirred at a temperature of 170 °C and a stirring rate of 800 r / min for 30 min. Then 4 g of aromatic oil was added, and it was sheared with a high-speed shearer at a temperature of 180 °C and a shear rate of 5000 r / min for 40 min. Then 0.3 g of sulfur was added, and it was stirred at a temperature of 185 °C and a stirring rate of 500 r / min for 30 min. Finally, it was placed in an oven for high-temperature development. The development temperature was 180 °C, and the development time was 30 min. Stirring was carried out 3 times during the high-temperature development process, stirring once every 10 min, to obtain the composite modified asphalt of amino-functionalized rubber powder modified with gallic acid / ethylenediamine groups grafted with epoxy-functionalized styrene-isoprene-styrene block copolymer.

[0060] 3. Modified asphalt self-healing mixture The preparation method is as follows: (1) Preparation of self-healing modified fiber 11 g of lignin fiber was added to 80 g of sodium hypochlorite aqueous solution (mass concentration 10 wt%), and it was stirred at a stirring rate of 300 r / min for 30 min. Then it was filtered, washed 3 times with deionized water, and then dried in an oven at 60 °C for 6 h to obtain oxidized fiber; the oxidized fiber was immersed in 80 g of hydrochloric acid solution with a mass concentration of 5 wt% for 40 min, then filtered, washed 3 times with deionized water, and dried in an oven at 60 °C for 6 h to obtain acid-treated fiber; 9 g of nano-silica and 3 g of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane were added to 150 g of ethanol aqueous solution with a mass concentration of 75 wt%, and it was stirred at a stirring rate of 400 r / min for 40 min to obtain a suspension; the acid-treated fiber was added to the suspension, placed in an ultrasonic disperser for ultrasonic dispersion, the ultrasonic time was 40 min, filtered, and then dried in an oven at 60 °C for 6 h to obtain self-healing modified fiber.

[0061] (1) Self-healing modified asphalt mixture 100 g of aggregate was subjected to high-temperature mixing at a mixing temperature of 175 °C for 90 s; 4 g of self-healing modified fiber was added for high-temperature mixing at a mixing temperature of 175 °C for 90 s; then 8 g of gallic acid / ethylenediamine group-modified amino-functionalized styrene-isoprene-styrene block copolymer composite modified asphalt was added for high-temperature mixing at a mixing temperature of 175 °C for 90 s; and then 5 g of mineral powder was added for high-temperature mixing at a mixing temperature of 175 °C for 90 s to obtain a gallic acid / ethylenediamine group-modified amino-functionalized styrene-isoprene-styrene block copolymer composite modified asphalt self-healing mixture.

[0062] Example 5 This example relates to the preparation of a 3,4-dihydroxystyrene / diethylenetriamine group-modified amino-functionalized styrene-isoprene-butadiene-styrene copolymer composite modifier, a composite modified asphalt, and a self-healing modified asphalt mixture.

[0063] 1. 3,4-Dihydroxystyrene / diethylenetriamine group-modified amino-functionalized styrene-isoprene-butadiene-styrene copolymer composite modifier The preparation method is as follows: (1) Preparation of 3,4-dihydroxystyrene / diethylenetriamine group-modified amino-functionalized rubber powder Add 11 g of rubber powder into 110 g of lithium hydroxide solution with a mass concentration of 5 wt%, stir at a stirring rate of 600 r / min for 30 min, then soak for 70 min, and then filter. Wash the obtained solid with deionized water three times, and then put it into an oven at 60 °C for drying for 6 h to obtain rubber powder a; mix 395 g of absolute ethanol and 0.5 g of γ-aminopropyltrimethoxysilane, stir for 30 min, and then let it stand for 1 h to obtain a hydrolysis solution. Add rubber powder a into the hydrolysis solution, stir at a stirring rate of 600 r / min for 30 min, let it stand for 1 h, take out the product, wash it with deionized water three times, and put it into an oven at 60 °C for drying for 6 h to obtain rubber powder b; add 2 g of 3,4-dihydroxystyrene, 2 g of diethylenetriamine, and 0.2 g of azobisisobutyronitrile aqueous solution (mass concentration of 1 wt%) into 180 g of 1,4-dioxane, and stir and react at 60 °C and a stirring rate of 600 r / min for 3 h to obtain a prepolymer mixed solution. Add rubber powder b and 0.2 g of triethylamine into the prepolymer mixed solution, and react at 60 °C and a stirring rate of 600 r / min for 4 h. After the reaction, centrifuge the reaction product at a centrifugal speed of 5500 r / min for 20 min, pour out the supernatant, and put the obtained solid into an oven at 60 °C for drying for 8 h to obtain 3,4-dihydroxystyrene / diethylenetriamine group-modified amino-functionalized rubber powder.

[0064] (2)Preparation of epoxy-functionalized styrene-isoprene-butadiene-styrene copolymer Add 8 g of styrene-isoprene-butadiene-styrene copolymer (SIBS, number average molecular weight 15000) into 90 g of n-hexane, stir at 80 °C until the styrene-isoprene-butadiene-styrene copolymer (SIBS) is completely dissolved to obtain a mixed solution, then add 1 g of peroxybenzoic acid and 0.2 g of polyethylene glycol monomethyl ether (number average molecular weight 2000), keep the temperature at 80 °C, stir for 1 h, dropwise add 4 g of hydrogen peroxide aqueous solution (dropwise addition rate is 2 s / drop, concentration is 30 wt%), after the dropwise addition is completed, react at 80 °C for 3 h. After the reaction, naturally cool to room temperature, add 300 g of absolute ethanol to the obtained reaction solution to coagulate and precipitate the reaction product, filter, and put the obtained solid into an oven at 60 °C for drying for 6 h to obtain epoxy-functionalized styrene-isoprene-butadiene-styrene block copolymer.

[0065] (3)Preparation of 3,4-dihydroxystyrene / diethylenetriamine group-modified amino-functionalized rubber powder grafted epoxy-functionalized styrene-isoprene-butadiene-styrene copolymer composite modifier 9 g of epoxy-functionalized styrene-isoprene-butadiene-styrene copolymer was added to 90 g of cyclohexane, 20 g of 3,4-dihydroxystyrene / diethylenetriamine group-modified amino-functionalized rubber powder was added, and 0.5 g of tetrabutylammonium bromide was added. The mixture was stirred and reacted at 60 °C and a stirring rate of 500 r / min for 3 h. After the reaction, it was filtered, and the obtained solid was dried in an oven at 60 °C for 6 h to obtain a 3,4-dihydroxystyrene / diethylenetriamine group-modified amino-functionalized rubber powder grafted epoxy-functionalized styrene-isoprene-butadiene-styrene copolymer composite modifier.

[0066] 2. Composite modified asphalt The preparation method is as follows: 110 g of No. 70 petroleum asphalt was heated to a flowing state, 27 g of 3,4-dihydroxystyrene / diethylenetriamine group-modified amino-functionalized rubber powder grafted epoxy-functionalized styrene-isoprene-butadiene-styrene copolymer composite modifier was added, and the mixture was stirred at a temperature of 170 °C and a stirring rate of 800 r / min for 30 min. Then 4 g of furfural extract oil was added, and it was sheared by a high-speed shearer at a temperature of 180 °C and a shear rate of 5000 r / min for 40 min. Then 0.4 g of alumina was added, and the mixture was stirred at a temperature of 185 °C and a stirring rate of 500 r / min for 30 min. Finally, it was placed in an oven for high-temperature development. The development temperature was 180 °C, and stirring was carried out 3 times during the high-temperature development process, stirring once every 10 min, to obtain 3,4-dihydroxystyrene / diethylenetriamine group-modified amino-functionalized rubber powder grafted epoxy-functionalized styrene-isoprene-butadiene-styrene copolymer composite modified asphalt.

[0067] 3. Modified asphalt self-healing mixture The preparation method is as follows: (1) Preparation of self-healing modified fiber 12 g of mineral fiber was added to 90 g of hydrogen peroxide aqueous solution (mass concentration of 20 wt%), and the mixture was stirred at a stirring rate of 300 r / min for 30 min. Then it was filtered, washed 3 times with deionized water, and then dried in an oven at 60 °C for 6 h to obtain oxidized fiber; the oxidized fiber was immersed in 80 g of hydrochloric acid solution with a mass concentration of 5 wt% for 40 min, then filtered, washed 3 times with deionized water, and dried in an oven at 60 °C for 6 h to obtain acid-treated fiber; 9 g of carbon nanotubes and 3 g of aminopropyltriethoxysilane were added to 150 g of ethanol aqueous solution with a mass concentration of 75 wt%, and the mixture was stirred at a stirring rate of 400 r / min for 40 min to obtain a suspension; the acid-treated fiber was added to the suspension, placed in an ultrasonic disperser for ultrasonic dispersion, the ultrasonic time was 40 min, filtered, and then dried in an oven at 60 °C for 6 h to obtain self-healing modified fiber.

[0068] (1) Self-healing modified asphalt mixture Mix 100 g of aggregate at a high temperature of 175 °C for 90 s; add 3 g of self-healing modified fiber and mix at a high temperature of 175 °C for 90 s; then add 9 g of 3,4-dihydroxystyrene / diethylenetriamine group-modified amino-functionalized rubber powder grafted epoxy-functionalized styrene-isoprene-butadiene-styrene copolymer composite modified asphalt and mix at a high temperature of 175 °C for 90 s; then add 6 g of mineral powder and mix at a high temperature of 175 °C for 90 s to obtain a 3,4-dihydroxystyrene / diethylenetriamine group-modified amino-functionalized rubber powder grafted epoxy-functionalized styrene-isoprene-butadiene-styrene copolymer composite modified asphalt self-healing mixture.

[0069] Comparative Example 1 This comparative example provides the above unmodified No. 70 base asphalt produced by Sinopec Corporation, and its related indicators are shown in Table 1 above.

[0070] Comparative Example 2 This comparative example relates to the preparation of epoxy-functionalized styrene-ethylene-butene-styrene block copolymer modified asphalt and modified asphalt self-healing mixture. Its preparation method is as shown in Example 1 above; different from Example 1, in this comparative example, the usage amount of 4-tert-butylcatechol / hexamethylenediamine group-modified amino-functionalized rubber powder is 0 g.

[0071] The specific preparation method is as follows: 1. Epoxy-functionalized styrene-ethylene-butene-styrene block copolymer Its preparation method is the same as that in Example 1.

[0072] 2. Epoxy-functionalized styrene-ethylene-butene-styrene block copolymer composite modified asphalt Its preparation method is the same as that in Example 1, the difference is that: use epoxy-functionalized styrene-ethylene-butene-styrene block copolymer to replace 4-tert-butylcatechol / hexamethylenediamine group-modified amino-functionalized rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer composite modifier to obtain epoxy-functionalized styrene-ethylene-butene-styrene block copolymer composite modified asphalt.

[0073] 3. Modified asphalt self-healing mixture The preparation method is the same as that of Example 1, except that: epoxy-functionalized styrene-ethylene-butene-styrene block copolymer composite modified asphalt is used instead of 4-tert-butylcatechol / hexamethylenediamine group modified amino-functionalized rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer composite modified asphalt to obtain epoxy-functionalized styrene-ethylene-butene-styrene block copolymer composite modified asphalt self-healing mixture.

[0074] Comparative Example 3 This comparative example relates to the preparation of activated rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer modified asphalt and modified asphalt self-healing mixture. The preparation method is as shown in Example 1 above; different from Example 1, in this comparative example, the usage amount of the compound containing catechol / polyamine group and amino-functional group is 0 g.

[0075] 1. Activated rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer composite modifier Its preparation method is as follows: (1) Preparation of activated rubber powder Add 12 g of rubber powder into 100 g of potassium hydroxide solution with a mass concentration of 5 wt%, stir at a stirring rate of 600 r / min for 30 min, then soak for 70 min, then filter, wash the obtained solid with deionized water for 3 times, filter, and then put it into an oven at 60 °C for drying for 6 h to obtain activated rubber powder.

[0076] (2) Preparation of epoxy-functionalized styrene-ethylene-butene-styrene block copolymer The same as Example 1.

[0077] (3) Preparation of activated rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer composite modifier Add 10 g of epoxy-functionalized styrene-ethylene-butene-styrene block copolymer into 80 g of cyclohexane, add 20 g of activated rubber powder, add 0.5 g of polyethylene glycol dimethyl ether (number average molecular weight 800), and stir at 60 °C and a stirring rate of 500 r / min for 3 h. After the reaction, filter, and dry the obtained solid in an oven at 60 °C for 6 h to obtain activated rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer composite modifier.

[0078] 2. Composite modified asphalt The preparation method is the same as that of Example 1, except that: an activated rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer composite modifier is used instead of the 4-tert-butylcatechol / hexamethylenediamine group-modified amino-functionalized rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer composite modifier to obtain an activated rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer composite modified asphalt.

[0079] 3. Modified asphalt self-healing mixture The preparation method is the same as that of Example 1, except that: an activated rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer composite modified asphalt is used instead of the 4-tert-butylcatechol / hexamethylenediamine group-modified amino-functionalized rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer composite modified asphalt to obtain an activated rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer composite modified asphalt self-healing mixture.

[0080] Comparative Example 4 This comparative example relates to the preparation of 4-tert-butylcatechol / hexamethylenediamine group-modified amino-functionalized rubber powder modified asphalt and a modified asphalt self-healing mixture. The preparation method is as shown in Example 1 above; different from Example 1, in this comparative example, the amount of the epoxy-functionalized styrene-ethylene-butene-styrene block copolymer used is 0.

[0081] The preparation method is as follows: 1. Preparation of 4-tert-butylcatechol / hexamethylenediamine group-modified amino-functionalized rubber powder The preparation method is the same as that of Example 1.

[0082] 2. Preparation of 4-tert-butylcatechol / hexamethylenediamine group-modified amino-functionalized rubber powder composite modified asphalt The preparation method is the same as that of Example 1, except that: 4-tert-butylcatechol / hexamethylenediamine group-modified amino-functionalized rubber powder is used instead of the 4-tert-butylcatechol / hexamethylenediamine group-modified amino-functionalized rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer composite modifier to obtain 4-tert-butylcatechol / hexamethylenediamine group-modified amino-functionalized rubber powder composite modified asphalt.

[0083] 3. Modified asphalt self-healing mixture The preparation method is the same as that of Example 1, except that: 4-tert-butylcatechol / hexamethylenediamine group-modified amino rubber powder composite modified asphalt is used to replace 4-tert-butylcatechol / hexamethylenediamine group-modified amino rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer composite modified asphalt, and 4-tert-butylcatechol / hexamethylenediamine group-modified amino rubber powder composite modified asphalt self-healing mixture is obtained.

[0084] Comparative Example 5 This comparative example relates to the preparation of 4-tert-butylcatechol / hexamethylenediamine group-modified amino rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer modified asphalt and modified asphalt mixture. The preparation method is as shown in Example 1 above; different from Example 1, in this comparative example, the usage amount of self-healing modified fiber is 0.

[0085] The preparation method is as follows: 1. 4-tert-butylcatechol / hexamethylenediamine group-modified amino rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer composite modifier The preparation method is the same as that of Example 1.

[0086] 2. Composite modified asphalt The preparation method is the same as that of Example 1.

[0087] 3. Composite modified asphalt mixture The preparation method is as follows: 100 g of aggregate is subjected to high-temperature mixing at a mixing temperature of 175 °C for 90 s; then 8 g of 4-tert-butylcatechol / hexamethylenediamine group-modified amino rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer composite modified asphalt is added for high-temperature mixing at a mixing temperature of 175 °C for 90 s; then 5 g of mineral powder is added for high-temperature mixing at a mixing temperature of 175 °C for 90 s to obtain 4-tert-butylcatechol / hexamethylenediamine group-modified amino rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer composite modified asphalt mixture.

[0088] Comparative Example 6 This comparative example relates to the preparation of unmodified rubber powder modified asphalt, and the preparation method is as follows: Heat 100 g of No. 70 petroleum asphalt to a flowing state, add 25 g of unmodified rubber powder, stir for 30 min at a temperature of 170 °C and a stirring rate of 800 r / min, then add 3 g of furfural extract oil, and use a high-speed shearer to shear for 40 min at a temperature of 180 °C and a shear rate of 5000 r / min. Then add 0.3 g of sulfur and stir for 30 min at a temperature of 185 °C and a stirring rate of 500 r / min. Finally, put it into an oven for high-temperature development. The development temperature is 180 °C and the development time is 30 min. Stir 3 times during the high-temperature development process, stirring once every 10 min, to obtain unmodified rubber powder modified asphalt.

[0089] I. Performance Tests of Functionalized Rubber Powder and Functionalized Block Copolymer 1. Contact Angle Test The contact angle test is a common method for characterizing the wettability of a sample to be tested by measuring the contact angle formed when a liquid drops on the surface of the sample to be tested. By means of the contact angle test, the hydrophilicity method of the surface of the functionalized rubber powder is evaluated. If the contact angle is less than 90°, it proves that the sample is hydrophilic; if the contact angle is greater than 90°, it proves that the sample is hydrophobic. The test results are as Figure 1 shown.

[0090] Figure 1 shows the contact angle of water on the surfaces of different types of rubber powders. It can be seen from Figure (a) that the unmodified ordinary rubber powder still has non-polar characteristics due to various impurities remaining on the surface, resulting in poor hydrophilicity and the largest contact angle; it can be seen from Figure (b) that the contact angle of the amino-functionalized rubber powder modified by 4-tert-butylcatechol / hexamethylenediamine groups decreases significantly and is less than 90°, showing an obvious hydrophilic effect. This is because the amino group, as a typical polar group, and catechol also introduce polar groups, and the two act synergistically to improve the polar state of the rubber powder surface, so the contact angle decreases and shows hydrophilic characteristics; it can be seen from Figure (c) that due to the grafting reaction between the amino-functionalized rubber powder modified by 4-tert-butylcatechol / hexamethylenediamine groups and the epoxy-functionalized styrene-ethylene-butene-styrene block copolymer, and the styrene-ethylene-butene-styrene block copolymer has obvious hydrophobic characteristics, the contact angle between the amino-functionalized rubber powder modified by 4-tert-butylcatechol / hexamethylenediamine groups and the epoxy-functionalized styrene-ethylene-butene-styrene block copolymer increases, showing hydrophobic characteristics, which is beneficial to improving the interfacial adhesion and compatibility when the composite modifier combines with asphalt.

[0091] 2. Swelling Index Test The swelling index test is a method for evaluating the ability of a sample material to interact with a solvent by measuring the volume or mass change of the sample material after being soaked in a specific solvent. The surface polarity state of the functionalized rubber powder and its dispersibility with asphalt are evaluated through the swelling index. The solvent used is toluene. The test results are asFigure 2 as shown

[0092] It can be seen from Figure 2 that the unmodified rubber powder has the lowest swelling index, indicating poor surface polarity, poor dispersibility and easy agglomeration, which affect the modification effect of the subsequent modified asphalt. The swelling index of the amino-functionalized rubber powder modified with 4-tert-butylcatechol / hexamethylenediamine group is higher than that of the unmodified rubber powder, indicating good activation degree. The swelling index of the amino-functionalized rubber powder modified with 4-tert-butylcatechol / hexamethylenediamine group grafted with epoxy-functionalized styrene-ethylene-butene-styrene block copolymer is the highest, indicating an increase in active sites and the best compatibility when combined with asphalt subsequently.

[0093] 3. Scanning electron microscope test The surface morphology and structural characteristics of the functionalized rubber powder can be observed through the scanning electron microscope test. The test results are as Figure 3 shown

[0094] It can be seen from Figure 3 (a) that for the unmodified rubber powder, there are granular impurities and raised parts on its surface. This is because the rubber powder is obtained by crushing waste tires and itself is composed of rubber, carbon black and other impurities, which still remain on the surface of the rubber powder. It can be seen from Figure 3 (b) that for the amino-functionalized rubber powder modified with 4-tert-butylcatechol / hexamethylenediamine group, the grooves and raised parts on the surface of the functionalized rubber powder increase, and there are a large number of microcracks among them, and the distance between particles decreases, changing the original surface state of the rubber powder. It can be seen from Figure 3 (c) that for the amino-functionalized rubber powder modified with 4-tert-butylcatechol / hexamethylenediamine group grafted with epoxy-functionalized styrene-ethylene-butene-styrene block copolymer, a smooth and dense network film structure is formed on its surface, proving that the amino-functionalized rubber powder modified with 4-tert-butylcatechol / hexamethylenediamine group is successfully grafted with the epoxy-functionalized styrene-ethylene-butene-styrene block copolymer.

[0095] 4. Infrared spectroscopy test Infrared spectroscopy is a spectral technique that can measure the infrared light absorption characteristics of substances and then analyze their chemical structures and component compositions. The composition of the sample is defined by analyzing the different functional groups contained therein. The infrared spectrum of the amino-functionalized rubber powder modified with 4-tert-butylcatechol / hexamethylenediamine group grafted with epoxy-functionalized styrene-ethylene-butene-styrene block copolymer in Example 1 is as Figure 4 shown

[0096] It can be seen through Figure 4 that the absorption peak appearing at 3431 cm -1 is caused by the superimposed vibration of N-H in NH2, indicating that the surface of the amino-functionalized rubber powder carries amino groups; at 2826 cm -1 and 786 cm-1 The absorption peaks appearing at [specific location] are respectively the characteristic peaks of the stretching vibrations of the C-H bond and C-O bond of the epoxy group, indicating that the epoxy-functionalized block copolymer is grafted onto the surface of the functionalized rubber powder; at 3015 cm -1 The absorption peak appearing at [specific location] is the stretching vibration peak of the =CH group in the block copolymer, and the absorption peak appearing at 961 cm -1 The absorption peak appearing at [specific location] is the C-H bending vibration in the butadiene double bond of the block copolymer, indicating that the functionalized rubber powder is successfully grafted with the epoxy-functionalized block copolymer.

[0097] II. Performance Testing and Evaluation of Composite Modified Asphalt 1. Penetration, Softening Point, and 5°C Ductility Tests of Composite Modified Asphalt The three major indexes of asphalt are used as the basic parameters to evaluate asphalt, corresponding to different properties of asphalt respectively. Penetration evaluates the hardness and softness of asphalt at normal temperature; softening point evaluates the high-temperature stability of asphalt; 5°C ductility evaluates the low-temperature plastic deformation ability of asphalt. To investigate the compatibility, high- and low-temperature properties, and other properties of the composite modifier prepared in the examples and asphalt, according to the requirements in the "Test Procedures for Bitumen and Bituminous Mixtures for Highway Engineering" (JTGE20 - 2011), tests of different experiments were carried out. Table 2 respectively shows the test results of the penetration, softening point, and 5°C ductility of different modified asphalts.

[0098] Table 2

[0099] When the penetration is low, the consistency of asphalt increases and the asphalt becomes hard; when the penetration is high, the fluidity of asphalt becomes stronger and the asphalt is softer. As can be seen from Table 2, by comparing Examples 1 - 5 with Comparative Examples 1 - 4, the penetration of Comparative Examples 1 - 4 is significantly higher than that of Examples 1 - 5, indicating that the modified asphalt incorporated with the amino-functionalized rubber powder grafted with epoxy-functionalized block copolymer modified by catechol / polyamine groups has a tightly cross-linked internal structure, effectively improving the overall consistency of the modified asphalt and ensuring the anti-deformation ability of the modified asphalt. Among them, according to Comparative Examples 1 - 4, it is found that the penetration of the base asphalt is the highest, which is because for the modified asphalts incorporated with different modifiers, with the aid of the interaction between the modifier and asphalt molecules, the overall consistency of asphalt is improved.

[0100] The higher the softening point, the stronger the high-temperature stability of the asphalt; the lower the softening point, the poorer the heat resistance of the asphalt. The softening point reflects the stability and plasticity of the asphalt at high temperatures. As can be seen from Table 2, the softening points of Examples 1-5 are significantly higher than those of Comparative Examples 1-4. Among them, the softening point of Example 3 reaches a maximum of 74 °C, indicating that after the asphalt is modified with the amino-functionalized rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer modified by 4-tert-butylcatechol / hexamethylenediamine groups, the amino-functionalized rubber powder modified by 4-tert-butylcatechol / hexamethylenediamine groups and the epoxy-functionalized styrene-ethylene-butene-styrene block copolymer act synergistically to construct a cross-linked network in the asphalt, restrict the thermal movement of molecules, improve the anti-deformation ability of the modified asphalt, and at the same time enhance the interfacial compatibility between the composite modifier and the asphalt, thereby improving the high-temperature stability of the modified asphalt, and its softening point is the highest.

[0101] The ductility at 5 °C reflects the ductility and crack resistance of the asphalt at low temperatures. The greater the ductility at 5 °C, the stronger the low-temperature toughness of the asphalt; the smaller the ductility at 5 °C, the more likely the asphalt is to crack at low temperatures. As can be seen from Table 2, compared with Examples 1-5, the ductility at 5 °C of Comparative Examples 1-4 has decreased significantly, especially the ductility at 5 °C of the matrix asphalt is the smallest, indicating that without the action of the composite modifier, the matrix asphalt alone cannot effectively adapt to the low-temperature environment due to its internal components and has poor crack resistance.

[0102] In summary, the amino-functionalized rubber powder grafted epoxy-functionalized block copolymer composite modifier modified by catechol / polyamine groups effectively improves the high-temperature stability and low-temperature crack resistance of the modified asphalt, and has an important impact on the performance of the asphalt.

[0103] 2. Storage stability test of composite modified asphalt The asphalt storage stability test mainly evaluates the compatibility and storage stability index of the modified asphalt by measuring the difference in the softening point of segregation. The greater the difference in the softening point of segregation, the more serious the phase separation of the modifier in the asphalt, the poorer the compatibility and the worse the storage stability; the smaller the difference in the softening point of segregation, the better the compatibility and storage stability of the modified asphalt. From Figure 5It can be seen that the softening point differences of Examples 1 to 5 are significantly smaller than those of Comparative Examples 1 to 4, indicating good compatibility of each example. This is because catechol and polyamine groups form a dynamic network through hydrogen bonds. This network can still maintain a certain strength at high temperatures and later undergoes a ring-opening reaction with epoxy groups to form a three-dimensional network structure. The amino-functionalized rubber powder modified by catechol / polyamine groups and the epoxy-functionalized block copolymer are grafted and crosslinked into an integral structure and act together inside the asphalt. This network structure restricts the migration of other components such as asphaltenes and resins, ensures the interaction between the composite modifier and asphalt molecules, and improves the compatibility and storage stability of the modified asphalt. For Comparative Examples 1 to 4, the softening point difference of the matrix asphalt in Comparative Example 1 is significantly greater than that in Comparative Examples 2 to 4. This is because the matrix asphalt lacks the action of modifiers or crosslinking agents and is prone to light and heavy component separation during high-temperature storage, resulting in a larger segregation softening point difference. Compared with Comparative Example 1, for the modified asphalt in Comparative Examples 2 to 4 with only epoxy-functionalized styrene-ethylene-butene-styrene block copolymer or activated rubber powder grafted with epoxy-functionalized styrene-ethylene-butene-styrene block copolymer or activated rubber powder grafted with styrene-ethylene-butene-styrene block copolymer added, its segregation softening point difference decreases significantly and its storage stability is also better than that in Comparative Example 1. This is because the modifier realizes chemical crosslinking and interaction inside the asphalt, improving the compatibility of the modified asphalt.

[0104] 3. Fluorescence microscope test The fluorescence microscope test can evaluate the compatibility, dispersibility, and interfacial interaction effect of the modified asphalt. The fluorescence microscope tests were carried out on the modified asphalt prepared in Comparative Example 6, Comparative Example 2, and Example 1, and the fluorescence test results are as Figure 6 shown.

[0105] From Figure 6 Figure (a), it can be seen that the rubber powder itself does not emit light and shows a black morphology throughout. It was observed that only when the rubber powder acts inside the asphalt, the rubber powder will show agglomeration and uneven dispersion, and cannot effectively improve the compatibility of the modified asphalt. From Figure 6 Figure (b), it can be seen that the block copolymer itself will show a green fluorescence morphology under blue light excitation. After the epoxy-functionalized styrene-ethylene-butene-styrene block copolymer is subjected to high-speed shearing, the overall morphology shows that green fluorescent dots are evenly dispersed inside the asphalt, and the distribution is uniform, continuous, and dense, effectively improving the overall compatibility between the epoxy-functionalized styrene-ethylene-butene-styrene block copolymer and the modified asphalt. From Figure 6As can be seen from (c), for the modified asphalt with the composite modifier of 4-tert-butylcatechol / hexamethylenediamine group-modified amino-functionalized crumb rubber grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer, it is relatively clear to observe that the composite modifier presents a three-dimensional network state inside the asphalt, cross-linking with each other and tightly intertwined, which proves that the compatibility between the 4-tert-butylcatechol / hexamethylenediamine group-modified amino-functionalized crumb rubber and the epoxy-functionalized styrene-ethylene-butene-styrene block copolymer in the modified asphalt is further improved, forming a mutually stable cross-linked structure.

[0106] 4. Phase Angle and Complex Shear Modulus The modified asphalt obtains the phase angle and complex shear modulus parameters based on the dynamic shear rheology test. Among them, the phase angle is used to characterize the viscoelastic properties of the asphalt, and the complex shear modulus is used to characterize the deformation resistance ability and high-temperature stability of the asphalt. In the present invention, by performing a temperature sweep test on the modified asphalt with the composite modifier, the changes of the phase angle and complex shear modulus with temperature are observed. When the phase angle is smaller and the complex shear modulus is larger, the deformation resistance ability of the asphalt is stronger and its high-temperature stability is better. The test results are as Figures 7 - 8 shown.

[0107] From Figures 7 - 8It can be seen that the complex shear modulus of the modified asphalt prepared in Examples 1-3 and Comparative Examples 1-4 shows a downward trend with the increase of temperature, and its phase angle shows a gradually increasing trend with the increase of temperature. This is because as the temperature rises, the thermal motion between asphalt molecules becomes more intense, the intermolecular interaction weakens, and the asphalt gradually transforms from an elastic component to a viscous component. When the asphalt is subjected to shear action, relative displacement and deformation are more likely to occur in the asphalt, resulting in an increase in the phase angle and a decrease in the complex shear modulus. By comparing Examples 1-3 with Comparative Examples 1-4, it can be seen that the modification effects are all Composite functionalized graft modifier > Single functionalized graft modifier > Single functionalized modifier > Unmodified. This is because the composite modifier after graft modification can effectively form a stable chemical structure with asphalt molecules and improve the high-temperature performance of asphalt. When the test temperature is the same, compared with Comparative Example 1 and Comparative Examples 2-4, since different composite modifiers are incorporated into the asphalt in Comparative Examples 2-4, affected by the epoxy-functionalized styrene-ethylene-butene-styrene block copolymer and the rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymer, one or two composite modifiers act together inside the asphalt, forming more molecular chain entanglements and cross-linking structures inside the asphalt, enhancing the shear resistance, and the elastic properties are relatively enhanced. Its complex shear modulus is increased to a certain extent and the phase angle is smaller. However, compared with Examples 1-3, the complex shear modulus of Comparative Examples 1-4 is significantly smaller than that of Examples 1-3, and its phase angle is also larger than that of Examples 1-3. This is because the composite modifiers added in Examples 1-3 are all amino-functionalized rubber powder grafted epoxy-functionalized styrene-ethylene-butene-styrene block copolymers modified by 4-tert-butylcatechol / hexamethylenediamine groups. Compared with Comparative Examples 1-4 without the co-grafting of the two, its complex shear modulus is relatively increased, the phase angle is relatively decreased, and the high-temperature stability is stronger.

[0108] 5. Rutting factor The rutting factor is the ratio of the complex shear modulus to the sine value of the phase angle, and is usually used as an important index to evaluate the high-temperature rutting resistance performance of asphalt, mainly used to characterize the ability of asphalt to resist permanent deformation under repeated loading at high temperatures. The test results are as Figure 9 shown.

[0109] From Figure 9It can be seen that as the temperature increases, the rutting factors of different modified asphalts all show a downward trend, indicating that under the influence of high temperature conditions, the overall performance of the asphalt changes, and it is more likely to undergo flow deformation, and its ability to resist rutting deformation also gradually weakens. At the same temperature, the rutting factors of Examples 1 to 3 are significantly higher than those of Comparative Examples 1 to 4, indicating that the high temperature rutting resistance of Examples 1 to 3 is higher than that of Comparative Examples 1 to 4, and the high temperature performance of Examples 1 to 3 is better. This is because the amino-functionalized rubber powder modified by 4-tert-butylcatechol / hexamethylenediamine groups grafts with the epoxy-functionalized styrene-ethylene-butene-styrene block copolymer and produces a chemical cross-linking phenomenon with the asphalt molecules, ensuring the stability of the internal structure of the asphalt. When subjected to external forces, the asphalt has good resistance, and its rutting factor is relatively high. However, the matrix asphalt shown in Comparative Example 1 has a significant decrease in its own performance as a whole under high temperature conditions due to the absence of any modifiers. The molecular chains of the asphalt move violently, and the ability to resist permanent deformation decreases significantly, and its rutting factor is the smallest.

[0110] 6. Low-temperature bending creep stiffness test The bending creep stiffness test is a test method for evaluating the low-temperature rheological properties of asphalt. It mainly measures the bending deformation degree of the asphalt specimen over time under a constant load in a low-temperature environment to obtain the creep stiffness and creep rate. The test results are as Figures 10 - 11 shown.

[0111] As Figures 10 - 11 shown, as the temperature gradually decreases, there is a trend that the creep stiffness of Examples 1 to 3 and Comparative Examples 1 to 4 gradually increases and the creep rate gradually decreases. This is because when the temperature decreases, the thermal motion inside the asphalt molecules weakens, the intermolecular friction increases, and the material gradually changes from a high-elastic state to a glassy state, thus showing higher rigidity and low deformation ability. At the same temperature, the creep stiffness of Examples 1 to 3 is significantly lower than that of Comparative Examples 1 to 4, and its creep rate is significantly higher than that of Comparative Examples 1 to 4. This is because Examples 1 to 3 are affected by the composite modifier, effectively improving the low-temperature flexibility and deformation resistance of the modified asphalt, and the low-temperature performance is significantly enhanced.

[0112] III. Performance influence test of the composite modifier modified asphalt self-healing mixture 1. Rutting test The rutting test of asphalt mixture is used to evaluate the permanent deformation resistance of asphalt mixture under high temperature conditions. It mainly simulates the repeated rolling action of wheel load on the road surface to evaluate the high temperature stability of asphalt mixture. The test results are shown in Table 3.

[0113] Table 3 High temperature rutting test results of modified asphalt mixture

[0114] As can be seen from Table 3, the dynamic stability of the self-healing asphalt mixture modified by the composite modifier in each embodiment is higher than the 3000 times / mm required by the specification, indicating that the synergistic effect of the amino rubber powder modified by the 4-tert-butylcatechol / hexamethylenediamine group and the epoxy functionalized styrene-ethylene-butylene-styrene block copolymer improves the compatibility and high temperature stability of the composite modifier modified asphalt. Because of the addition of self-healing fibers, the anti-rutting ability of the self-healing asphalt mixture is further improved, and it has good durability and extends the service life of the material. According to the comparison between Examples 1 to 3 and Comparative Example 5, since Comparative Example 5 lacks the addition of self-healing fibers, the dynamic stability of its modified asphalt mixture is significantly lower than that of Examples 1 to 3, indicating that the self-healing fibers contribute to the high temperature anti-rutting performance of the asphalt mixture, ensuring that if the asphalt mixture is slightly damaged and cracked in a high temperature environment, it can be repaired in time, thereby extending the service life of the asphalt mixture.

[0115] 8. Freeze-thaw splitting test The freeze-thaw splitting test is an important test method for evaluating the anti-stripping ability and water stability of asphalt mixtures under the action of water and low temperature cycles. It mainly simulates the damage to the pavement structure caused by water intrusion and freeze-thaw cycles in the natural environment, and then analyzes the adhesion between the asphalt and aggregate interface and the durability of the mixture. The test results are shown in Table 4 below.

[0116] Table 4 Results of freeze-thaw splitting test on self-healing asphalt mixture modified by composite modifier

[0117] As shown in Table 4, the freeze-thaw splitting strength ratios of Examples 1 to 3 are significantly greater than 70% of the specification requirement, indicating that the 4-tert-butylcatechol / hexamethylenediamine group-modified amino rubber powder grafted epoxy functionalized styrene-ethylene-butylene-styrene block copolymer modified asphalt self-healing mixture has excellent water stability and durability against freeze-thaw cycles. Compared with Comparative Example 5, it can be seen that the freeze-thaw splitting strength ratios of Examples 1 to 3 are significantly higher than those of Comparative Example 5. This is because Examples 1 to 3 not only have the ability to provide a cross-linked network support to the interior of the asphalt by the composite modifier, and form a strong interfacial bonding effect with the asphalt molecules, but also use the self-healing mechanism of the self-healing fiber to synergistically repair the microcracks generated by the freeze-thaw cycle, restore the continuity of the interfacial bonding, and delay the destruction time of the asphalt mixture.

[0118] 3. Four-point bending fatigue test The four-point bending fatigue test is a test method used to characterize the fatigue cracking resistance of asphalt mixtures under repeated loading. It mainly applies cyclic bending loads to standard beam specimens to simulate the stress state when vehicle loads act repeatedly on the pavement, and analyzes the overall process from crack generation to macroscopic failure of asphalt mixtures. The test results are shown in Table 5 below.

[0119] Table 5 Four-point bending fatigue test results of self-healing mixtures of composite modified asphalt

[0120] As can be seen from Table 5, the fatigue lives of Examples 1 to 3 are significantly higher than those of Comparative Examples 2 to 5. The fatigue lives of Examples 1 to 3 and Comparative Examples 2 to 5 all gradually decrease with the increase of the strain level. This is because at high strain levels, obvious stress concentration phenomena will occur inside the asphalt mixture, which is likely to cause molecular chain fracture or interface debonding, thereby accelerating the generation and development of microcracks and ultimately shortening the fatigue life of the asphalt mixture. Comparing Examples 1 to 3 with Comparative Example 5, it can be seen that the fatigue life of Comparative Example 5 is significantly less than that of each example. This is because self-healing fibers are not added in Comparative Example 5. Thus, when the material is subjected to load and generates microcracks, the self-healing repair mechanism of the self-healing fibers cannot be triggered, and then the cracks in the asphalt mixture gradually evolve into irreversible damage, affecting the fatigue life of the asphalt mixture.

Claims

1. A method for preparing a high-viscosity activated rubber powder grafted functionalized block copolymer composite modifier, characterized in that: The steps include: (1) Aminated rubber powder modified with catechol / polyamine groups The rubber powder is added into an alkaline solution, stirred evenly and then soaked, and then filtered, washed and dried to obtain rubber powder a; anhydrous ethanol and an amino group compound are mixed, stirred and allowed to stand to obtain a hydrolysis solution; Adding rubber powder a to the hydrolysis solution, stirring evenly and then standing, filtering, washing and drying to obtain rubber powder b; mixing catechol monomer, polyamine monomer, initiator aqueous solution and organic solvent A, stirring and reacting to obtain a prepolymer mixed solution; adding rubber powder b and catalyst I to the prepolymer mixed solution to react, and after the reaction is completed, centrifuging and drying to obtain catechol / polyamine group-modified amino rubber powder; (2) Functionalized block copolymers The block copolymer is added to the organic solvent B, stirred until dissolved to obtain a mixed solution, and then an organic acid and a catalyst II are added to the mixed solution, stirred, and then an aqueous hydrogen peroxide solution is added dropwise to react; after the reaction is completed, the mixture is cooled to room temperature, anhydrous ethanol is added to the reaction solution to condense and precipitate the reaction product, filtered, and dried to obtain an epoxy functionalized block copolymer; (3) Grafting reaction The epoxy functionalized block copolymer is dissolved in an organic solvent C, and catechol / polyamine group-modified aminated rubber powder and catalyst III are added, and the mixture is heated and stirred for reaction; after the reaction is completed, the mixture is filtered and dried to obtain a catechol / polyamine group-modified aminated rubber powder grafted epoxy functionalized block copolymer composite modifier, which is a high-viscosity activated rubber powder grafted functionalized block copolymer composite modifier.

2. The method for preparing the high-viscosity activated rubber powder grafted functionalized block copolymer composite modifier according to claim 1, characterized in that: In the preparation method of the composite modifier, in step (1), the raw materials are selected from the following parts by weight: 10-15 parts of rubber powder, 100-120 parts of alkaline solution, 300-500 parts of anhydrous ethanol, 0.1-2 parts of amino group compound, 0.5-3 parts of catechol monomer, 0.5-3 parts of polyamine monomer, 0.1-1 parts of initiator aqueous solution, 100-350 parts of organic solvent A, and 0.1-1 parts of catalyst I; In the preparation method of the composite modifier, in step (1), the mass concentration of the alkaline solution is 2-10wt%; the alkali in the alkaline solution is selected from one or more of sodium hydroxide, potassium hydroxide, lithium hydroxide, and barium hydroxide; the amino group compound is selected from one or more of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, and bis(γ-triethoxysilylpropyl)amine; the catechol monomer is selected from one or more of catechol, 4-tert-butylcatechol, 4-methylcatechol, 3,4-dihydroxystyrene, 3,4-dihydroxybenzoic acid, 4-(2-aminoethyl)benzene-1,2-diol, and gallic acid; the polyamine monomer is selected from one or more of ethylenediamine. The initiator is selected from one or more of potassium persulfate, ammonium persulfate, azobisisobutyronitrile, azobisisoheptanenitrile and benzoyl peroxide, and the mass concentration of the initiator aqueous solution is 0.5-1.5wt%; the organic solvent A is selected from one or more of methanol, ethanol, N,N-dimethylformamide, N-methylpyrrolidone, tetrahydrofuran, 1,4-dioxane, dichloromethane and chloroform; the catalyst I is selected from one or more of triethylamine, pyridine, sodium hydroxide, ammonia solution, laccase, tyrosinase, ferric chloride and ferric sulfate, and the mass concentration of the ammonia solution is 25-28wt%; In the preparation method of the composite modifier, in step (1), the rubber powder is added to the alkaline solution, and the stirring rate is 600-800 r / min, the stirring time is 30-40 min, and the soaking time is 30-100 min; after soaking in the alkaline solution, it is filtered, and the obtained solid is washed with deionized water for 3-5 times, and then dried at 50-60°C for 6-8 hours to obtain rubber powder a; in the preparation of the hydrolysis solution, after the anhydrous ethanol and the amino group compound are mixed, the stirring time is 30-40 min, and the standing time is 1-2 hours; the rubber powder a is added to the hydrolysis solution and stirred at a rate of 500-600 r / min, the stirring time is 30-40 min, and the standing time is 1-2 hours, then filtered, and the obtained solid is washed with deionized water for 3-5 times, and then dried at 50-60°C for 6-8 hours to obtain rubber powder a. The mixture was washed with water for 2 to 3 times, and then dried at 50 to 60°C for 6 to 8 hours to obtain rubber powder b; after the catechol monomer, polyamine monomer, initiator aqueous solution and organic solvent A were mixed, the stirring reaction conditions were as follows: the reaction temperature was 60 to 70°C, the stirring rate was 500 to 600 r / min, and the reaction time was 3 to 4 hours; the rubber powder b and catalyst I were added to the prepolymer mixed solution, and the reaction conditions were as follows: the reaction temperature was 60 to 70°C, the stirring rate was 600 to 800 r / min, and the reaction time was 3 to 4 hours; the centrifugal conditions were as follows: the centrifugal speed was 5000 to 6000 r / min, and the centrifugal time was 15 to 30 minutes; the drying conditions after centrifugation were as follows: the solid obtained by centrifugation was dried at 60 to 80°C for 6 to 8 hours.

3. The method for preparing the high-viscosity activated rubber powder grafted functionalized block copolymer composite modifier according to claim 1, characterized in that: In the preparation method of the composite modifier, in step (2), the raw materials are selected from the following parts by weight: 8-10 parts of block copolymer, 80-100 parts of organic solvent B, 0.8-1.2 parts of organic acid, 0.1-0.2 parts of catalyst II, 3-5 parts of aqueous hydrogen peroxide solution, and 200-400 parts of anhydrous ethanol; In the preparation method of the composite modifier, in step (2), the block copolymer is selected from at least one of styrene-butadiene-styrene copolymer, styrene-isoprene-styrene block copolymer, styrene-ethylene-butylene-styrene block copolymer, styrene-ethylene-propylene-styrene type block copolymer, styrene-ethylene-propylene copolymer, styrene-isoprene-butadiene-styrene copolymer; the organic solvent B is selected from one or more of cyclohexane, n-hexane, dichloromethane, N,N-dimethylformamide, N,N-diethylformamide, and toluene; the organic acid is selected from one or more of formic acid, m-chloroperbenzoic acid, perbenzoic acid, and peracetic acid; the catalyst II is selected from one or more of polyethylene glycol, polyethylene glycol dimethyl ether, polypropylene glycol, poloxamer, polyethylene glycol monomethyl ether, and polypropylene glycol block polyether, and the number average molecular weight of the catalyst II is 200-35000; the mass concentration of the hydrogen peroxide aqueous solution is 20-30wt%; In the preparation method of the composite modifier, in step (2), the block copolymer is added to the organic solvent B and stirred at a temperature of 60-80°C; the organic acid and the catalyst II are added to the mixed solution and stirred at a temperature of 60-80°C for 0.1-1h; the reaction is carried out after the hydrogen peroxide solution is added dropwise at a temperature of 60-80°C for 3-4h; and the drying is carried out at 50-60°C for 6-8h.

4. The method for preparing the high-viscosity activated rubber powder grafted functionalized block copolymer composite modifier according to claim 1, characterized in that: In the preparation method of the composite modifier, in step (3), the raw materials are selected from the following weight parts: 8-10 parts of epoxy functionalized block copolymer, 70-90 parts of organic solvent C, 20-25 parts of catechol / polyamine group-modified amino rubber powder, and 0.3-0.6 parts of catalyst III; In the preparation method of the composite modifier, in step (3), the organic solvent C is selected from one of cyclohexane, n-hexane, dichloromethane, N,N-dimethylformamide, N,N-diethylformamide, and toluene; the catalyst III is selected from one or more of polyethylene glycol, polyethylene glycol dimethyl ether, polypropylene glycol, tetrabutylammonium bromide, triethylbenzylammonium chloride, and poloxamer; the number average molecular weight of the polyethylene glycol, polyethylene glycol dimethyl ether, polypropylene glycol, or poloxamer is 200-35000; In the preparation method of the composite modifier, in the step (3), the conditions for the heating and stirring reaction are: reaction temperature of 60-80°C, stirring rate of 300-600 r / min, reaction time of 3-4 h; and the drying conditions are drying at 50-60°C for 6-8 h.

5. A high-viscosity activated rubber powder grafted functionalized block copolymer composite modifier, characterized in that: The preparation method is adopted according to any one of claims 1 to 4.

6. A method for preparing a composite modified asphalt, characterized in that: The steps include: Heat the base asphalt to a fluid state, add the high-viscosity activated rubber powder grafted functional block copolymer composite modifier described in claim 5, stir at high speed, then add a compatibilizer, shear at high speed, add a stabilizer, stir at low speed, and finally develop at high temperature to obtain a high-viscosity activated rubber powder grafted functional block copolymer composite modified asphalt.

7. The method for preparing the composite modified asphalt according to claim 6, characterized in that: In the preparation method of composite modified asphalt, each raw material is selected from the following parts by weight: 100-120 parts of base asphalt, 25-33 parts of high-viscosity activated rubber powder grafted functionalized block copolymer composite modifier, 3-6 parts of compatibilizer, and 0.3-0.6 parts of stabilizer; The matrix asphalt is selected from one or more of petroleum asphalt, natural asphalt, and coal asphalt; the compatibilizer is selected from one or more of furfural extracted oil, aromatic oil, rubber oil, and dibutyl phthalate; the stabilizer is selected from at least one of diethylenetriamine, triethylenetetramine, 2,6-di-tert-butyl-p-cresol, hydroquinone, magnesium oxide, magnesium carbonate, aluminum oxide, calcium oxide, calcium hydroxide, sulfur, montmorillonite, and kaolin; The conditions for high-speed stirring are: stirring temperature of 170-180°C, stirring rate of 800-1000r / min, and stirring time of 30-40min; the conditions for high-speed shearing are: shear temperature of 180-190°C, shear rate of 4500-5000r / min, and shear time of 40-50min; the conditions for low-speed stirring are: stirring temperature of 180-185°C, stirring rate of 500-600r / min, and stirring time of 30-40min; the conditions for high-temperature development are: temperature of 180-185°C, development time of 30-40min, and stirring is performed 3 times during the high-temperature development process, stirring once every 10-15min.

8. A composite modified asphalt, characterized in that: The product is prepared by the preparation method according to any one of claims 6 to 7.

9. Use of the composite modified asphalt according to claim 8 in preparing a modified asphalt self-healing mixture for road paving.

10. A modified asphalt self-healing mixture, characterized in that: Prepared according to the following method: (i) Preparation of self-healing modified fibers The fibers are added to an oxidant aqueous solution, stirred for oxidation treatment, filtered, washed, and dried to obtain oxidized fibers; the oxidized fibers are added to an acid solution for immersion, filtered, washed, and dried to obtain acid-treated fibers; the nanomaterials and silane coupling agents are added to an ethanol aqueous solution, stirred to obtain a suspension solution; The acid-treated fibers are added to the suspension solution, ultrasonically dispersed, filtered, and dried to obtain self-healing modified fibers; (ii) Preparation of modified asphalt self-healing mixture The aggregate is mixed at high temperature, and the self-healing modified fiber is added and mixed at high temperature; then the composite modified asphalt is added and mixed at high temperature; then the mineral powder is added and mixed at high temperature to obtain a high-viscosity modified asphalt self-healing mixture; Preferably, in step (i), each raw material is selected from the following parts by weight: 10-15 parts of fiber, 80-100 parts of oxidant aqueous solution, 80-120 parts of acidic solution, 6-12 parts of nanomaterial, 3-5 parts of silane coupling agent, and 120-180 parts of ethanol aqueous solution; In step (i), the fiber is selected from one or more of basalt fiber, glass fiber, lignin fiber, mineral fiber, polypropylene fiber, polyester fiber, carbon fiber, and straw fiber; the oxidant is selected from one of sodium hypochlorite, hydrogen peroxide, sodium dichloroisocyanurate, potassium dichromate, and potassium permanganate. When the oxidant is sodium hypochlorite, the mass concentration of the oxidant aqueous solution is 5-10wt%; when the oxidant is hydrogen peroxide, sodium dichloroisocyanurate, potassium dichromate, or potassium permanganate, the mass concentration of the oxidant aqueous solution is 10-20wt%; the acidic solution is selected from hydrochloric acid solution, nitric acid solution, phosphoric acid solution, acetic acid solution, oxalic acid solution, carbonic acid solution, The mass concentration of the acidic solution is 3-8wt%; the nanomaterial is selected from one or more of nano silicon dioxide, nano titanium dioxide, nano zinc oxide, carbon nanotubes, graphene, nano CoO, nano Fe3O4, and nano γ-Fe2O3; the silane coupling agent is selected from one or more of γ-aminopropyl triethoxysilane, N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane, N-β-(aminoethyl)-γ-aminopropyl methyl dimethoxysilane, aminopropyl triethoxysilane, and γ-aminopropyl triethoxysilane; the mass concentration of ethanol in the ethanol aqueous solution is 70-80wt%; In step (i), the conditions for oxidation treatment are as follows: stirring time is 30-60 min, stirring rate is 300-500 r / min; the conditions for soaking are as follows: soaking time is 30-60 min; the conditions for preparing suspension solution are as follows: stirring time is 30-40 min, stirring rate is 300-500 r / min; the conditions for ultrasonic dispersion are as follows: ultrasonic dispersion time is 30-40 min; the washing is performed by washing with deionized water for 3-5 times, and the drying is performed at 60-80° C. for 6-8 h; Preferably, in step (ii), the raw materials are selected from the following mass parts: 100-130 parts of aggregate, 2-4 parts of self-healing modified fiber, 8-10 parts of composite modified asphalt, and 5-6 parts of mineral powder; the conditions for the high-temperature mixing are: mixing temperature 175-185°C, mixing time 80-100s.

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