High viscoelastic modified asphalt based on waste EVA of photovoltaic panel and preparation method thereof

Abstract

The application relates to the technical field of road materials, and particularly discloses high-viscoelastic modified asphalt based on waste EVA of photovoltaic panels and a preparation method thereof. The preparation method of the high-viscoelastic modified asphalt is as follows: waste EVA of photovoltaic panels is first crushed, is activated by free radical polymerization grafting after being de-crosslinked by a de-crosslinking agent and a silane coupling agent containing an alkenyl group to obtain r-EVA; then, the r-EVA and a thermoplastic elastomer are sequentially added into hot asphalt for high-speed shearing and blending; and finally, the r-EVA and the thermoplastic elastomer are formed by a crosslinking agent reaction. The waste EVA is converted from solid waste into a functional modified component, not only forms a stable and compatible system with asphalt, but also produces a synergistic effect with an elastomer such as SBS. The obtained modified asphalt not only significantly reduces the SBS dosage, but also exhibits excellent high-temperature anti-rutting performance, high-elasticity recovery rate and outstanding storage stability, so that the dual targets of waste resource utilization and high performance of pavement materials are achieved.

Description

Technical Field

[0001] This invention relates to the field of road materials technology, and in particular to a highly viscoelastic modified asphalt based on waste EVA from photovoltaic panels and its preparation method. Background Technology

[0002] With the rapid development of high-grade highways and heavy-duty traffic, higher requirements are placed on the high-temperature rutting resistance, low-temperature cracking resistance, and fatigue resistance of asphalt pavements. High viscoelastic modified asphalt, due to its excellent comprehensive road performance, has become one of the key materials for constructing long-life pavements. Currently, high viscoelastic modified asphalt mainly uses styrene-based thermoplastic elastomers (such as SBS) to modify the base asphalt. However, SBS is expensive, and its modified asphalt not only keeps pavement costs high but also has poor thermal storage stability. On the other hand, the photovoltaic industry has generated a large amount of solid waste during its rapid development, among which waste EVA (ethylene-vinyl acetate copolymer) generated from the photovoltaic module lamination process is one of the main components. Because this type of EVA has undergone partial cross-linking during the lamination process (the degree of cross-linking is usually 70%-85%), it has insoluble and infusible properties, making traditional recycling extremely difficult. Currently, it is mostly disposed of through landfill or incineration, causing serious resource waste and environmental pollution.

[0003] The use of waste plastics for asphalt modification has been extensively studied and is considered a potential resource utilization approach. However, directly applying photovoltaic waste EVA to asphalt modification faces the following insurmountable technical bottlenecks: (1) Extremely poor compatibility: The solubility parameters of cross-linked EVA and asphalt do not match, and there is a lack of effective interfacial bonding. It is very easy for phase separation and segregation to occur in asphalt, resulting in unqualified storage stability of modified asphalt and rapid deterioration of performance.

[0004] (2) Difficulty in dispersion: Cross-linked EVA particles are difficult to melt and disperse in high-temperature asphalt, and often exist in the form of coarse particles. Not only can they not play a modifying role, but they may also become stress defect points and damage the performance of asphalt.

[0005] (3) Low modification efficiency: Untreated EVA lacks synergistic effect with asphalt and SBS and other elastomers. Compared with SBS modified asphalt, simple blending often leads to a decrease in the high temperature performance, low temperature performance and elastic recovery rate of modified asphalt, which cannot meet the technical requirements of high viscoelastic asphalt (GB / T 30516-2014).

[0006] Therefore, developing a technology that can effectively solve the compatibility problem between photovoltaic waste EVA and asphalt, and enable it to produce a synergistic effect with elastomers such as SBS, thereby producing high-performance, low-cost, high-viscoelastic modified asphalt, has significant environmental and economic value. Summary of the Invention

[0007] To address the shortcomings of the existing technologies, the primary objective of this invention is to provide a highly viscoelastic modified asphalt that efficiently utilizes waste photovoltaic EVA, significantly reduces dependence on SBS, and simultaneously achieves excellent and balanced high and low temperature performance and viscoelasticity. Another objective of this invention is to provide a method for preparing the aforementioned highly viscoelastic modified asphalt. This method, through a specific "one-step decrosslinking and interface activation" process, effectively solves the compatibility and dispersibility issues between waste EVA and asphalt, and achieves synergistic effects between EVA and SBS.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A highly viscoelastic modified asphalt is prepared from raw materials comprising the following parts by weight: 100 parts of base bitumen; 3-5 parts of thermoplastic elastomer; 2-5 parts of r-EVA; Crosslinking agent 0.5 to 3 parts.

[0009] Furthermore, the r-EVA is obtained by crushing waste EVA from photovoltaic panels, de-crosslinking it with a de-crosslinking agent, and then performing free radical polymerization and grafting activation with an alkenyl-containing silane coupling agent.

[0010] Preferably, the base asphalt is 70# base asphalt or 90# base asphalt.

[0011] Preferably, the thermoplastic elastomer is a styrene-based thermoplastic elastomer, and more preferably at least one of linear styrene-butadiene-styrene block copolymer (SBS), hydrogenated styrene-butadiene-styrene block copolymer (SEBS), styrene-butadiene rubber (SBR), or hydrogenated styrene-butadiene rubber (SEBR).

[0012] Preferably, the crosslinking agent is one of tert-butyl peroxide-2-ethylhexanoate, dicumyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and benzoyl peroxide, mixed with sulfur in a mass ratio of (1~3):1.

[0013] The waste EVA from photovoltaic panels refers to the scraps generated during the lamination process of photovoltaic modules. EVA stands for ethylene-vinyl acetate copolymer, with a VA value of 28% to 33% and a crosslinking degree of 70% to 85%.

[0014] The decrosslinking agent is at least one of 2,2'-dithiodibenzoic acid, monoethanolamine, zinc acetate, tetrabutyl titanate, or dibutyltin oxide.

[0015] The alkenyl-containing silane coupling agent is vinyltrimethoxysilane or vinyltriethoxysilane.

[0016] Furthermore, the process of obtaining r-EVA is carried out with the participation of a plasticizer, which is at least one of aromatic oil, naphthenic oil, epoxidized soybean oil, or phthalate plasticizers.

[0017] The weight ratio of waste EVA from photovoltaic panels, decrosslinking agent, and alkenyl-containing silane coupling agent is 100:0.8~3.5:1~4.

[0018] The weight ratio of waste EVA and plasticizer in photovoltaic panels is 100:3.5~8.

[0019] Secondly, the present invention provides a method for preparing the above-mentioned highly viscoelastic modified asphalt, comprising the following steps: (1) De-crosslinking and interface activation: After crushing the waste EVA from photovoltaic panels, it is mixed with plasticizer, de-crosslinking agent and alkenyl-containing silane coupling agent. The mixture is then added to a mixer and kneaded under heating and shearing to obtain the treated EVA mixture, abbreviated as r-EVA. (2) Composite modification: By weight, the base asphalt is heated to 160~185℃, and under high-speed shear, the r-EVA and thermoplastic elastomer obtained in step (1) are added in sequence for shear blending; then a crosslinking agent is added and the reaction is carried out under stirring to obtain the high viscoelastic modified asphalt.

[0020] Preferably, in step (1), the plasticizer is at least one of aromatic oil, naphthenic oil, epoxidized soybean oil or phthalate plasticizer; the decrosslinking agent is at least one of 2,2'-dithiodibenzoic acid, monoethanolamine, zinc acetate, tetrabutyl titanate or dibutyltin oxide; and the alkenyl-containing silane coupling agent is vinyltrimethoxysilane or vinyltriethoxysilane.

[0021] In step (1), the weight ratio of waste EVA from photovoltaic panels, plasticizer, decrosslinking agent and silane coupling agent is 100:3.5~8:0.8~3.5:1~4.

[0022] In step (1), the shearing speed is 90~150 rpm, the heating temperature is 100~160℃, and the mixing time is 15~40 minutes.

[0023] Preferably, in step (2), the high-speed shearing speed is 4000~6000 r / min, and the shearing and blending time is 90~120 minutes; after adding the crosslinking agent, the mixture is stirred at 800~1000 r / min for 30~60 minutes at 170~185℃.

[0024] Compared with the prior art, the superior effects of the present invention are: 1. Achieved high-value utilization of waste photovoltaic panel EVA: This invention adopts a one-step process of "de-crosslinking and interface activation" for the treatment of highly crosslinked EVA waste from photovoltaic panels, transforming it from "insoluble and infusible" solid waste into a functional polymer modifier that is well compatible with asphalt, opening up a new and high-value-added application channel for this type of difficult-to-recycle waste.

[0025] 2. Excellent compatibility and storage stability: Through the bridging effect of alkenyl-containing silane coupling agents, a strong chemical bond and physical adsorption are formed between r-EVA and asphalt, which completely solves the phase separation problem and meets the requirements for commercial storage and transportation.

[0026] 3. Significant synergistic effect and excellent performance: The decrosslinked EVA flexible long chain and SBS network are intertwined and form a dense system with asphalt, which significantly improves the storage stability of modified asphalt and increases the dynamic viscosity at 60℃, achieving the dual goals of "turning waste into treasure" and "upgrading performance".

[0027] 4. By adding waste photovoltaic panel EVA to partially replace SBS, the raw material cost of high viscoelastic modified asphalt can be significantly reduced while ensuring or even improving performance, resulting in huge economic and social benefits. Attached Figure Description

[0028] Figure 1 This is an appearance diagram of the waste EVA material used in the photovoltaic panels of this invention; Figure 2 This is the appearance diagram of r-EVA obtained in step (1) of Example 1; Figure 3 Here is an image of the modified asphalt prepared in Example 1; Figure 4 The image shows the fluorescence pattern of the modified bitumen prepared in Example 2 (scale bar 100 μm). Figure 5 The fluorescence image of the modified bitumen prepared in Comparative Example 3 (scale bar 100 μm). Figure 6 The fluorescence image of the modified bitumen prepared in Comparative Example 4 (scale bar 100 μm). Figure 7 The fluorescence image of the modified bitumen prepared in Comparative Example 5 is shown (scale bar 100 μm). Detailed Implementation

[0029] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0030] The raw materials used in the following embodiments and comparative examples are described below: Waste EVA from photovoltaic panels (ethylene-vinyl acetate copolymer): This is a scrap material generated during the lamination process of photovoltaic modules, sourced from Changzhou Trina Solar Co., Ltd. The VA value (the mass percentage of vinyl acetate in the copolymer) is 28.3%. The degree of crosslinking was determined as follows: Waste EVA from photovoltaic panels was dissolved in xylene organic solvent, then extracted in a hot water bath for 6 hours using Soxhlet extraction. The extract was distilled to remove the solvent and dried to obtain the sol content. The residue in the filter paper was dried to obtain the gel content. The degree of crosslinking was calculated based on the ratio of gel content to (sol content + gel content), and the measured result was 79.7%.

[0031] SBS (styrene-butadiene-styrene block copolymer): sourced from Sinopec Hunan Petrochemical Co., Ltd., with an S / B mass ratio of 30 / 70. Example 1:

[0032] A highly viscoelastic modified asphalt based on waste EVA from photovoltaic panels is prepared by weight of the following materials: 100 parts of 90# base asphalt, 5 parts of SBS, 2 parts of r-EVA, and 0.5 parts of dicumyl peroxide composite sulfur (DCP and sulfur mass ratio 1:1).

[0033] Prepare according to the following steps: (1) By weight, each part is 1g, and 100 parts of waste EVA from photovoltaic panels (see its appearance picture) are prepared. Figure 1 After being crushed using a plastic crusher, the resulting material, less than 10mm in length, is mixed with 5.0 parts of plasticizer aromatic oil, 1.5 parts of decrosslinking agent 2,2'-dithiodibenzoic acid, and 2.0 parts of silane coupling agent vinyltrimethoxysilane. This mixture is then added to an internal mixer and sheared and kneaded for 30 minutes at 100 rpm and 140°C to obtain the treated EVA mixture, abbreviated as r-EVA. Figure 2 As shown; (2) By weight, 100 parts of 90# base asphalt were heated to 175°C and, under high-speed shearing conditions of 5000 r / min, 2 parts of r-EVA obtained in step (1) and 5 parts of thermoplastic elastomer SBS were added sequentially, and shearing was performed for 100 min; then 0.5 parts of dicumyl peroxide composite sulfur (DCP, sulfur mass ratio 1:1) crosslinking agent were added, and the mixture was stirred and reacted at 180°C and 1000 r / min for 45 min to obtain the high viscoelastic modified asphalt, as shown in the figure. Figure 3 As shown. Example 2:

[0034] A highly viscoelastic modified asphalt based on waste EVA from photovoltaic panels is prepared by weight of the following materials: 100 parts of 90# base asphalt, 4 parts of SBS, 3 parts of r-EVA, and 0.5 parts of dicumyl peroxide composite sulfur (DCP and sulfur mass ratio 1:1).

[0035] The preparation method is the same as in Example 1.

[0036] The fluorescence pattern of the modified bitumen prepared in Example 2 is shown in the figure. Figure 4 . Example 3:

[0037] A highly viscoelastic modified asphalt based on waste EVA from photovoltaic panels is prepared by weight of the following materials: 100 parts of 90# base asphalt, 3 parts of SBS, 4 parts of r-EVA, and 0.5 parts of dicumyl peroxide composite sulfur (DCP and sulfur mass ratio 1:1).

[0038] The preparation method is the same as in Example 1. Example 4:

[0039] A highly viscoelastic modified asphalt based on waste EVA from photovoltaic panels is prepared by weight of the following materials: 100 parts of 90# base asphalt, 3 parts of SBS, 5 parts of r-EVA, and 0.5 parts of dicumyl peroxide composite sulfur (DCP and sulfur mass ratio 1:1).

[0040] The preparation method is the same as in Example 1.

[0041] Comparative Example 1: A highly viscoelastic modified asphalt based on waste EVA from photovoltaic panels is prepared by weight of the following materials: 100 parts of 90# base asphalt, 2 parts of SBS, 5.0 parts of r-EVA, and 0.5 parts of dicumyl peroxide composite sulfur (DCP and sulfur mass ratio 1:1).

[0042] The preparation method is the same as in Example 1.

[0043] Comparative Example 2: A highly viscoelastic modified asphalt, by weight, is prepared from the following materials: 100 parts of 90# base asphalt, 7 parts of SBS, and 0.5 parts of dicumyl peroxide composite sulfur (DCP and sulfur in a mass ratio of 1:1).

[0044] Prepare according to the following steps: By weight, 100 parts of 90# base asphalt were heated to 175°C and 7 parts of thermoplastic elastomer SBS were added under high-speed shearing at 5000 r / min. The mixture was sheared and blended for 100 min. Then, 0.5 parts of dicumyl peroxide composite sulfur (mass ratio 1:1) crosslinking agent were added and the mixture was stirred and reacted at 180°C and 1000 r / min for 45 min to obtain the high viscoelastic modified asphalt.

[0045] Comparative Example 3: A highly viscoelastic modified asphalt based on waste EVA from photovoltaic panels is prepared by weight of the following materials: 100 parts of 90# base asphalt, 4 parts of SBS, 3 parts of waste EVA from photovoltaic panels, and 0.5 parts of dicumyl peroxide composite sulfur (DCP and sulfur mass ratio 1:1).

[0046] Prepare according to the following steps: By weight, 100 parts of 90# base asphalt were heated to 175°C and, under high-speed shearing conditions of 5000 r / min, 3 parts of waste EVA from photovoltaic panels and 4 parts of thermoplastic elastomer SBS were added sequentially, and shearing was carried out for 100 min. Then, 0.5 parts of dicumyl peroxide composite sulfur (DCP, sulfur mass ratio 1:1) crosslinking agent were added, and the mixture was stirred at 180°C and 1000 r / min for 45 min to obtain the high viscoelastic modified asphalt.

[0047] The fluorescence spectrum of the modified bitumen prepared in Comparative Example 3 is shown in Figure 3. Figure 5 .

[0048] Comparative Example 4: A highly viscoelastic modified asphalt based on waste EVA from photovoltaic panels is prepared by weight of the following materials: 100 parts of 90# base asphalt, 4 parts of SBS, 3 parts of r-EVA-J, and 0.5 parts of dicumyl peroxide composite sulfur (DCP and sulfur mass ratio 1:1).

[0049] Prepare according to the following steps: (1) By weight, each part is 1g. 100 parts of waste EVA from photovoltaic panels are crushed by a plastic crusher to obtain crushed material with a length of less than 10mm. This material is then mixed with 5.0 parts of plasticizer aromatic oil and 1.5 parts of decrosslinking agent 2,2'-dithiodibenzoic acid. The mixture is then added to a mixer and sheared and mixed for 30 minutes at a speed of 100 rpm and a temperature of 140℃ to obtain the treated EVA mixture, abbreviated as r-EVA-J. (2) By weight, 100 parts of 90# base asphalt were heated to 175°C and 3 parts of r-EVA-J obtained in step (1) and 4 parts of thermoplastic elastomer SBS were added in sequence under high-speed shearing speed of 5000 r / min. The mixture was sheared and blended for 100 min. Then, 0.5 parts of dicumyl peroxide composite sulfur (DCP, sulfur mass ratio 1:1) crosslinking agent were added and stirred at 180°C and 1000 r / min for 45 min to obtain the high viscoelastic modified asphalt.

[0050] The fluorescence pattern of the modified bitumen prepared in Comparative Example 4 is shown in the figure. Figure 6 .

[0051] Comparative Example 5: A highly viscoelastic modified asphalt based on waste EVA from photovoltaic panels is prepared by weight of the following materials: 100 parts of 90# base asphalt, 4 parts of SBS, 3 parts of r-EVA-O, and 0.5 parts of dicumyl peroxide composite sulfur (DCP and sulfur mass ratio 1:1).

[0052] Prepare according to the following steps: (1) By weight, each part is 1g. 100 parts of waste EVA from photovoltaic panels are crushed by a plastic crusher to obtain crushed material with a length of less than 10mm. This material is mixed with 5.0 parts of plasticizer aromatic oil and 2.0 parts of silane coupling agent vinyltrimethoxysilane. The mixture is added to a mixer and sheared and mixed for 30 minutes at a speed of 100 rpm and a temperature of 140℃ to obtain the treated EVA mixture, abbreviated as r-EVA-O. (2) By weight, 100 parts of 90# base asphalt were heated to 175°C and 3 parts of r-EVA-O obtained in step (1) and 4 parts of thermoplastic elastomer SBS were added in sequence under high-speed shearing speed of 5000 r / min. The mixture was sheared and blended for 100 min. Then, 0.5 parts of dicumyl peroxide composite sulfur (DCP, sulfur mass ratio 1:1) crosslinking agent were added and stirred at 180°C and 1000 r / min for 45 min to obtain the high viscoelastic modified asphalt.

[0053] The fluorescence pattern of the modified bitumen prepared in Comparative Example 5 is shown in the figure. Figure 7 .

[0054] Test Example 1 The modified asphalt samples prepared in Examples 1-4 and Comparative Examples 1-5 were subjected to performance tests. The performance tests included softening point, ductility at 5°C, elastic recovery rate at 25°C, dynamic viscosity at 60°C, and segregation test, specifically referring to JTGE20-2025 "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering". The performance test results are shown in Table 1.

[0055] Table 1. Performance test results of the example samples and comparative sample samples. As shown in Table 1, the modified asphalts prepared in Examples 1-4 all have softening points greater than 80℃, ductility at 5℃ greater than 30cm, elastic recovery rate at 25℃ greater than or equal to 85%, dynamic viscosity at 60℃ greater than 20000 Pa·s, and segregation results less than 2.5℃, meeting the requirements of GB / T 30516-2014 "High Viscosity and High Elasticity Road Asphalt". However, the modified asphalt in Comparative Example 1 is inferior to that in Examples 1-4 in all four indicators: softening point, ductility at 5℃, elastic recovery rate at 25℃, and dynamic viscosity at 60℃. This is mainly because the SBS content is low, failing to achieve a synergistic effect with r-EVA. Therefore, the recommended mass ratio y of thermoplastic elastomer to r-EVA is 0.6 ≤ y ≤ 2.5.

[0056] Comparing Examples 1-4 with Comparative Example 2, it is evident that Comparative Example 2, which uses a high dosage of SBS to modify asphalt, does not meet the specifications for asphalt segregation. This indicates that r-EVA, while partially replacing SBS, can also increase the viscosity of the modified asphalt and improve its storage stability. This invention achieves high-value utilization of waste EVA from photovoltaic panels.

[0057] The test results of modified asphalt in Examples 1-4 and Comparative Examples 3-5 show that the addition of the decrosslinking agent mainly decrosslinks the EVA material, generating more active sites. Simultaneously, the added interfacial activating material, the silane coupling agent, can undergo free radical polymerization and graft onto the broken EVA chains, resulting in a uniform and dense three-dimensional interpenetrating network structure formed by EVA, asphalt, and SBS, greatly enhancing the high and low temperature performance and viscoelastic properties of the modified asphalt. The segregation results indicate that untreated EVA cannot form a synergistic effect with SBS, resulting in poor system stability. Figure 4 , Figure 5 , Figure 6 and Figure 7 It can also be seen that, Figure 4 The dispersion is uniform, and the dispersed phase size is small. Figure 5 The uneven dispersion and large size of the dispersed phase clearly demonstrate that untreated EVA cannot effectively form a synergistic and homogeneous dispersion with thermoplastic elastomers in modified asphalt; while Figure 6The dispersed phase is relatively large and shows a tendency to aggregate, indicating that the interfacial bonding of the untreated system is weak and its stability is poor. Figure 7 Because the cross-linking process is not completed, the dispersed phases are spaced far apart and unevenly dispersed, resulting in weak synergistic effects. Therefore, both untreated and partially treated EVA-modified systems exhibit poor dispersion.

Claims

1. A highly viscoelastic modified asphalt, characterized in that, It is prepared from the following raw materials in parts by weight: 100 parts base bitumen; 3-5 parts of thermoplastic elastomer; 2-5 parts of r-EVA; Crosslinking agent 0.5-3 parts; The r-EVA is obtained by crushing waste EVA from photovoltaic panels, de-crosslinking it with a de-crosslinking agent, and then performing free radical polymerization and grafting activation with an alkenyl-containing silane coupling agent.

2. The high viscoelastic modified asphalt according to claim 1, characterized in that, The base asphalt is 70# or 90# base asphalt; and / or the thermoplastic elastomer is a styrene-based thermoplastic elastomer.

3. The high viscoelastic modified asphalt according to claim 1, characterized in that, The thermoplastic elastomer is at least one of linear styrene-butadiene-styrene block copolymer, hydrogenated styrene-butadiene-styrene block copolymer, styrene-butadiene rubber, or hydrogenated styrene-butadiene rubber.

4. The high viscoelastic modified asphalt according to claim 1, characterized in that, The crosslinking agent is one of the following: tert-butyl peroxide-2-ethylhexanoate, dicumyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and benzoyl peroxide, mixed with sulfur in a mass ratio of 1 to 3:

1.

5. The high viscoelastic modified asphalt according to claim 1, characterized in that, The waste EVA from photovoltaic panels is scrap material generated during the photovoltaic module lamination process, with a VA value of 28%~33% and a crosslinking degree of 70%~85%.

6. The high viscoelastic modified asphalt according to claim 1, characterized in that, The decrosslinking agent is at least one of 2,2'-dithiodibenzoic acid, monoethanolamine, zinc acetate, tetrabutyl titanate, or dibutyltin oxide; and / or The alkenyl-containing silane coupling agent is vinyltrimethoxysilane or vinyltriethoxysilane.

7. The high viscoelastic modified asphalt according to claim 6, characterized in that, The process of obtaining r-EVA is carried out with the participation of a plasticizer, which is at least one of aromatic oil, naphthenic oil, epoxidized soybean oil, or phthalate plasticizer.

8. The high viscoelastic modified asphalt according to claim 7, characterized in that, The weight ratio of waste EVA from photovoltaic panels, decrosslinking agent, and alkenyl-containing silane coupling agent is 100:0.8~3.5:1~4; and / or The weight ratio of waste EVA and plasticizer in photovoltaic panels is 100:3.5~8.

9. The method for preparing the highly viscoelastic modified asphalt according to any one of claims 1 to 8, characterized in that, Includes the following steps: (1) De-crosslinking and interface activation: After crushing the waste EVA from photovoltaic panels, it is mixed with plasticizer, de-crosslinking agent and alkenyl-containing silane coupling agent. The mixture is then added to a mixer and kneaded under heating and shearing to obtain the treated EVA mixture, abbreviated as r-EVA. (2) Composite modification: By weight, the base asphalt is heated to 160~185℃, and under high-speed shear, the r-EVA and thermoplastic elastomer obtained in step (1) are added in sequence for shear blending; then a crosslinking agent is added and the reaction is carried out under stirring to obtain the high viscoelastic modified asphalt.

10. The preparation method according to claim 9, characterized in that, In step (1), the shearing speed is 90~150 rpm, the heating temperature is 100~160℃, and the mixing time is 15~40 minutes; In step (2), the high-speed shearing speed is 4000~6000 r / min, and the shearing and blending time is 90~120 minutes; after adding the crosslinking agent, the mixture is stirred at 800~1000 r / min for 30~60 minutes at 170~185℃.

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