High-content compounded waste rubber powder modified asphalt, preparation method and application thereof

Abstract

This invention discloses a high-content compounded waste rubber powder modified asphalt, its preparation method, and its application. The modified asphalt comprises the following raw materials in parts by weight: 360-410 parts of base asphalt, 0-168 parts of waste nylon tire rubber powder, and 0-168 parts of desulfurized rubber powder, with the ratio of desulfurized rubber powder to waste nylon tire rubber powder being 0.30-0.77. This invention also discloses a method for preparing the high-content compounded waste rubber powder modified asphalt. This invention uses the above-mentioned method for preparing the high-content compounded waste rubber powder modified asphalt, blending partially desulfurized rubber powder with waste nylon tire rubber powder for asphalt modification. This significantly increases the rubber powder content while maintaining high levels of high and low temperature performance, storage stability, and processing performance of the modified asphalt.

Description

Technical Field

[0001] This invention relates to the field of asphalt modification technology, and in particular to a high-content compound waste rubber powder modified asphalt, its preparation method, and its application. Background Technology

[0002] With the gradual improvement of living standards and the rapid development of the logistics industry, my country's car ownership has been increasing year by year. The increase in the number of vehicles has driven the development of the automobile tire industry. However, the continuous consumption and wear of automobile tires has also generated a lot of waste tires. The amount of waste tires generated each year is increasing at a rate of 8% to 10%, but the recycling rate is only about 50%. Resource recycling of waste tires, expanding the pathways for resource recycling, and reducing resource waste are among the problems that need to be solved at this stage.

[0003] On the other hand, the development of the automotive industry has led to increasing pressure on road transportation, resulting in higher demands for road asphalt and improved pavement performance. Studies have shown that, compared to SBS-modified asphalt, using widely available and inexpensive waste rubber powder to modify asphalt can impart good high and low temperature performance, while also recycling waste car tires, resulting in significant environmental benefits. However, the current rubber powder content in rubberized asphalt is around 20%. With increasing content, rubber powder-modified asphalt exhibits a series of problems such as high viscosity, easy segregation, and difficulty in construction, posing significant challenges to engineering units and limiting the increase in rubber powder content and further improvement of rubberized asphalt pavement performance.

[0004] To address the difficulty in increasing the rubber powder content in waste rubber powder modified asphalt, current solutions involve desulfurizing and modifying ordinary rubber powder or treating it with various activators. This often involves prolonged high-temperature swelling and high-speed shearing processes. However, this can cause rubber molecules to transform from a network structure to a branched structure with smaller molecular weights, thereby destroying the cross-linking structure and causing the polymer backbone to break down. Although this can increase the waste rubber powder content and reduce the construction viscosity, the basic properties of the modified asphalt prepared are far inferior to those of ordinary waste rubber powder modified asphalt.

[0005] Therefore, there is an urgent need to propose a method for preparing and applying high-performance asphalt modified with high amounts of waste rubber powder. Summary of the Invention

[0006] The purpose of this invention is to provide a high-content compound waste rubber powder modified asphalt, its preparation method and application. Partially desulfurized rubber powder is blended with waste nylon tire rubber powder and then used for asphalt modification. This significantly increases the rubber powder content while also improving the high and low temperature performance, storage stability and processing performance of the modified asphalt.

[0007] To achieve the above objectives, the present invention provides a high-content compound waste rubber powder modified asphalt, comprising the following raw materials in parts by weight: 360-410 parts of base asphalt, 0-168 parts of waste nylon tire rubber powder, and 0-168 parts of desulfurized rubber powder, wherein the compounding ratio of the amount of desulfurized rubber powder to waste nylon tire rubber powder is 0.30-0.77.

[0008] Preferably, the particle size of the waste nylon tire rubber powder is 0.2 to 0.6 mm; the particle size of the desulfurized rubber powder is 0.2 to 0.6 mm.

[0009] Preferably, the matrix asphalt comprises 380-390 parts, the total mass of waste nylon tire rubber powder and desulfurized rubber powder is 43% of the matrix asphalt addition, the mass of waste nylon tire rubber powder is 30% of the matrix asphalt addition, and the mass of desulfurized rubber powder is 13% of the matrix asphalt addition.

[0010] A method for preparing high-content compounded waste rubber powder modified asphalt includes the following steps:

[0011] Step 1: Mix waste nylon tire rubber powder and desulfurized rubber powder evenly to obtain compound rubber powder, and dry it in an oven;

[0012] Step 2: The compounded rubber powder obtained in Step 1 is added to the base asphalt to modify it, and then sheared and emulsified to obtain waste rubber powder modified asphalt.

[0013] Preferably, in step one, the drying temperature in the oven is 70–80°C, and the drying time is 9–12 hours.

[0014] Preferably, in step two, the modification is carried out under stirring conditions, the modification temperature is 190-200℃, the stirring speed is 1000-1300rpm, and the holding time is 50-60min.

[0015] Preferably, in step two, the temperature of shear emulsification is 190-200℃, the rotation speed is 2000-5000 rpm, and the time is 30-50 min.

[0016] Preferably, in step two, the shear emulsification is segmented shear emulsification, which includes a first-stage shear emulsification and a second-stage shear emulsification. The rotation speed of the first-stage shear emulsification is 2000-3000 rpm, and the time is 10-15 min. The rotation speed of the second-stage shear emulsification is 4000-5000 rpm, and the time is 20-35 min.

[0017] A method for preparing high-content compound waste rubber powder modified asphalt, and its application in road engineering.

[0018] The advantages and positive effects of the high-content compound waste rubber powder modified asphalt, its preparation method, and its application described in this invention are as follows:

[0019] 1. This invention uses a mixture of undesulfurized nylon tire waste rubber powder and partially desulfurized rubber powder. Under conventional preparation conditions, it significantly increases the rubber powder content while ensuring good road performance of the modified asphalt. It not only solves the problems of poor compatibility, high viscosity, and easy segregation of modified asphalt with high content of ordinary waste rubber powder, but also solves the problem of decreased high-temperature performance of modified asphalt caused by the destruction of the cross-linking structure of desulfurized rubber powder and the reduction of molecular weight.

[0020] 2. The cross-linked network structure of undesulfurized nylon tire rubber powder after swelling enhances the high and low temperature performance of asphalt; while the cross-linked structure of desulfurized rubber powder is destroyed, the molecular weight is smaller and easier to process, it dissolves quickly with the base asphalt and the modified system formed is stable and not easy to separate. After mixing and compounding the two, the preparation temperature of modified asphalt is reduced and the preparation time is shortened. While ensuring the stability of the system, the comprehensive performance of various aspects is improved. The resulting waste rubber powder modified asphalt has a high softening point, moderate penetration and good elastic recovery performance; it has excellent low temperature toughness, high temperature stability, fatigue resistance and processability.

[0021] 3. This invention ensures that the swelling and degradation of desulfurized and non-desulfurized rubber powder in the base asphalt are optimal by controlling the rotation speed, temperature and time of the stirring and shear emulsification stages. This allows the modified asphalt to have good basic road performance while also having the advantages of low viscosity and high storage stability under high rubber powder content.

[0022] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0023] Figure 1 These are storage stability performance diagrams for Examples 1-3 and Comparative Examples 2-3 of the present invention; Detailed Implementation

[0024] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0025] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains. Unless otherwise defined, all materials used in this invention are commercially available.

[0026] A high-content compounded waste rubber powder modified asphalt comprises the following raw materials in parts by weight: 360-410 parts of base asphalt, 0-168 parts of waste nylon tire rubber powder, and 0-168 parts of desulfurized rubber powder. The base asphalt comprises 380-390 parts, and the base asphalt is one or both of No. 70 and No. 90.

[0027] The particle size of waste nylon tire rubber powder is 0.2–0.6 mm; the particle size of desulfurized rubber powder is 0.2–0.6 mm (this particle size refers to the particle size of the desulfurized rubber powder before desulfurization). By screening rubber powder with appropriate particle size, the performance of modified asphalt can be optimized. Rubber powder with excessively large particle size will cause the viscosity of modified asphalt to increase after swelling, while rubber powder with excessively small particle size will result in insufficient performance of modified asphalt.

[0028] The base asphalt consists of 380-390 parts, with the total mass of waste nylon tire rubber powder and desulfurized rubber powder accounting for 43% of the base asphalt addition. The waste nylon tire rubber powder accounts for 30% of the base asphalt addition, and the desulfurized rubber powder accounts for 13%. Selecting an appropriate amount of waste nylon tire rubber powder optimizes the high-temperature stability of the modified asphalt. Different amounts of waste nylon tire rubber powder have varying effects on base asphalt modification. As the amount increases, the high-temperature performance of the modified asphalt improves. However, because waste nylon tire rubber powder retains its undesulfurized cross-linked structure and has very few surface-active groups, using too much will lead to incompatibility with the base asphalt, resulting in high viscosity, easy segregation, and reduced conventional properties. Selecting an appropriate amount of desulfurized rubber powder can reduce the viscosity of the modified asphalt and increase system stability. However, the main chain and cross-linked structure of desulfurized rubber powder are damaged, resulting in a small molecular weight; excessive amounts will severely degrade the performance of the modified asphalt.

[0029] Under the premise that the total amount of waste rubber powder is preferably 43% of the base asphalt, the proportions of desulfurized rubber powder and waste nylon tire rubber powder are continuously adjusted to find the optimal compounding ratio: under the condition that the rubber powder content is 43%, the compounding ratio K of desulfurized rubber powder and waste nylon tire rubber powder is 0.30 to 0.77, preferably 0.30 to 0.54, and more preferably 0.30 to 0.31.

[0030] The blending ratio K of desulfurized rubber powder and waste nylon tire rubber powder is calculated using the following formula: A × 43% × K = A × DR. (A: mass of base asphalt, K: blending ratio, DR: percentage content of desulfurized rubber). Taking 13% desulfurized rubber powder + 30% waste nylon tire rubber powder as an example, assuming the total rubber powder content is 43%, to calculate the blending ratio of desulfurized rubber powder and nylon rubber powder in this formula, simply substitute the mass of base asphalt and the percentage content of desulfurized rubber powder in the formula into the formula.

[0031] A method for preparing high-content compounded waste rubber powder modified asphalt includes the following steps:

[0032] Step 1: Mix waste nylon tire rubber powder and desulfurized rubber powder evenly to obtain compound rubber powder, and dry it in an oven;

[0033] Step 2: The compounded rubber powder obtained in Step 1 is added to the base asphalt to modify it, and then sheared and emulsified to obtain waste rubber powder modified asphalt.

[0034] In step one, the oven drying temperature is 70-80℃, and the drying time is 9-12 hours.

[0035] In step two, the modification is carried out under stirring conditions. The modification temperature is 190–200℃, the stirring speed is 1000–1300 rpm, and the holding time is 50–60 min. If the stirring temperature is too low or the stirring time is too short, the rubber powder will not be able to fully absorb the lightweight components in the asphalt, resulting in incomplete swelling and poor performance of the modified asphalt.

[0036] In step two, the temperature for shear emulsification is 190–200℃, the rotation speed is 2000–5000 rpm, and the time is 30–50 min.

[0037] In step two, shear emulsification is performed in stages, including a single-stage and a two-stage process. The single-stage shear emulsification operates at a rotation speed of 2000–3000 rpm for 10–15 minutes; the two-stage shear emulsification operates at a rotation speed of 4000–5000 rpm for 20–35 minutes. During shear emulsification, excessively short time or low temperature will prevent the modified asphalt viscosity from decreasing, while excessively high rotation speed will lead to excessive shear degradation of the asphalt powder, resulting in poor modified asphalt performance.

[0038] A method for preparing high-content compounded waste rubber powder modified asphalt is disclosed, and the waste rubber powder modified asphalt is applied in road engineering. Waste rubber powder modified asphalt can be used in road engineering, is easy to process and construct, can improve the performance of road surfaces, and uses solid waste materials as raw materials, resulting in low cost, environmental friendliness, and significant economic and social benefits.

[0039] Example 1

[0040] A high-content compound waste rubber powder modified asphalt comprises the following raw materials in parts by weight: 390g of base asphalt No. 90, 39g of waste nylon tire rubber powder, and 128.7g of desulfurized rubber powder.

[0041] A method for preparing high-content compounded waste rubber powder modified asphalt includes the following steps:

[0042] (1) Mix the waste nylon tire rubber powder and desulfurized rubber powder of the above quality evenly to obtain compound rubber powder, wash with anhydrous ethanol until the solution is clear and transparent, and put it into an oven to dry at 70℃ for 12h.

[0043] (2) The dry compound rubber powder and the above-mentioned mass of base asphalt are dispersed and modified by a high-speed mixer for 55-60 minutes at a temperature of 190-195℃ and a stirring speed of 1100-1200rpm.

[0044] (3) After mixing and modification, the resulting mixture is sheared and emulsified in a high-speed shear emulsifier at a temperature of 190-195℃ for 10 minutes at a speed of 2000-2500 rpm; then the temperature is controlled at 190-195℃, the speed is increased to 5000 rpm, and shearing and emulsifying is carried out for 35 minutes to obtain compound waste rubber powder modified asphalt.

[0045] Example 2

[0046] A high-content compound waste rubber powder modified asphalt comprises the following raw materials in parts by weight: 390g of base asphalt No. 90, 78g of waste nylon tire rubber powder, and 89.7g of desulfurized rubber powder.

[0047] A method for preparing high-content compounded waste rubber powder modified asphalt includes the following steps:

[0048] (1) Mix the waste nylon tire rubber powder and desulfurized rubber powder of the above quality evenly to obtain compound rubber powder, wash with anhydrous ethanol until the solution is clear and transparent, and put it into an oven to dry at 70℃ for 12h.

[0049] (2) The dry compound rubber powder and the above-mentioned mass of base asphalt are dispersed and modified by a high-speed mixer for 55-60 minutes at a temperature of 190-195℃ and a stirring speed of 1100-1200rpm.

[0050] (3) After mixing and modification, the resulting mixture is sheared and emulsified in a high-speed shear emulsifier at a temperature of 190-195℃ for 10 minutes at a speed of 2000-2500 rpm; then the temperature is controlled at 190-195℃, the speed is increased to 5000 rpm, and shearing and emulsifying is carried out for 35 minutes to obtain compound waste rubber powder modified asphalt.

[0051] Example 3

[0052] A high-content compound waste rubber powder modified asphalt comprises the following raw materials in parts by weight: 390g of base asphalt No. 90, 117g of waste nylon tire rubber powder, and 50.7g of desulfurized rubber powder.

[0053] A method for preparing high-content compounded waste rubber powder modified asphalt includes the following steps:

[0054] (1) Mix the waste nylon tire rubber powder and desulfurized rubber powder of the above quality evenly to obtain compound rubber powder, wash with anhydrous ethanol until the solution is clear and transparent, and put it into an oven to dry at 70℃ for 12h.

[0055] (2) The dry compound rubber powder and the above-mentioned mass of base asphalt are dispersed and modified by a high-speed mixer for 55-60 minutes at a temperature of 190-195℃ and a stirring speed of 1100-1200rpm.

[0056] (3) After mixing and modification, the resulting mixture is sheared and emulsified in a high-speed shear emulsifier at a temperature of 190-195℃ for 10 minutes at a speed of 2000-2500 rpm; then the temperature is controlled at 190-195℃, the speed is increased to 5000 rpm, and shearing and emulsifying is carried out for 35 minutes to obtain compound waste rubber powder modified asphalt.

[0057] Comparative Example 1

[0058] 390g of base asphalt No. 90.

[0059] Comparative Example 2

[0060] A method for preparing high-content waste rubber powder modified asphalt includes the following steps: 167.7g of desulfurized rubber powder is washed with anhydrous ethanol and dried at 70℃ for 12h. The dried rubber powder and base asphalt are then dispersed and modified using a high-speed mixer for 55-60min at a temperature of 190-195℃ and a stirring speed of 1100-1200rpm. After mixing and modification, the resulting mixture is sheared and emulsified in a high-speed shear emulsifier at 190-195℃ for 10min at a speed of 2000-2500rpm. Then, the temperature is controlled at 190-195℃, the speed is increased to 5000rpm, and shearing and emulsification is continued for 35min to obtain waste rubber powder modified asphalt.

[0061] Comparative Example 3

[0062] A method for preparing high-content waste rubber powder modified asphalt comprises the following steps: 167.7g of 40-mesh waste nylon tire rubber powder is washed with anhydrous ethanol and dried at 70℃ for 12h. The dried rubber powder is then mixed with base asphalt and dispersed in a high-speed mixer for 55-60min at a temperature of 190-195℃ and a stirring speed of 1100-1200rpm. After mixing and modification, the resulting mixture is sheared and emulsified in a high-speed shear emulsifier at 190-195℃ for 10min at a speed of 2000-2500rpm. Then, the temperature is controlled at 190-195℃, the speed is increased to 5000rpm, and shearing and emulsification is continued for 35min to obtain waste rubber powder modified asphalt.

[0063] The amounts of each component used in Examples 1-3 and Comparative Examples 1-3 are shown in Table 1:

[0064] Table 1

[0065]

[0066] In Table 1, NCR is 40-mesh waste nylon tire rubber powder, DCR is desulfurized rubber powder, and the base asphalt is No. 90 asphalt; the equipment used is a high-speed mixer and a high-speed shear dispersion emulsifier. The rubber powder used in Comparative Example 2 is pure desulfurized rubber powder, and its addition amount accounts for 43% of the base asphalt. The rubber powder used in Comparative Example 3 is pure waste nylon tire rubber powder, and its addition amount accounts for 43% of the base asphalt. In Examples 1-3, under the condition that the total content of waste nylon tire rubber powder and desulfurized rubber powder is 43% of the base asphalt, the two types of rubber powder are compounded, and the content of waste nylon tire rubber powder is continuously increased to seek optimal performance. When optimal performance is achieved, the mass of waste nylon tire rubber powder is 30% of the base asphalt addition amount, and the mass of desulfurized rubber powder is 13% of the base asphalt addition amount.

[0067] For the high-dosage compound waste rubber powder modified asphalt / base asphalt of Examples 1-3 and Comparative Examples 1-3, the low-temperature toughness of the modified asphalt was tested by the 5℃ ductility test; the high-temperature stability of the modified asphalt was characterized by the softening point test; the hardness and consistency of the modified asphalt were characterized by the 25℃ penetration test; the fatigue resistance of the modified asphalt was characterized by the elastic recovery test; and the ease of construction of the modified asphalt was characterized by the rotational viscosity at 180℃. The results are shown in Table 2.

[0068] Table 2

[0069]

[0070] As shown in Table 2, for high-content blended waste rubber powder modified asphalt, with the increase of the proportion of waste nylon tire rubber powder (i.e., undesulfurized rubber powder) in the blended rubber powder, its low-temperature toughness is improved to a certain extent; high-temperature stability is significantly improved; elastic recovery and penetration index can continue to maintain a good level. At the same time, the low viscosity of the blended rubber powder modified asphalt also gives it good processing and road application performance. In Examples 1-3, the blending ratio K of desulfurized rubber powder and waste nylon tire rubber powder is 0.77, 0.53, and 0.30, respectively. Compared with Comparative Examples 2 and 3, the ductility of Example 3 increased by 41.29% and 5.50%, respectively, and the softening point increased by 6.12% and 7.11%, respectively; compared with Examples 1 and 2, the ductility of Example 3 increased by 39.24% and 22.44%, respectively, and the softening point increased by 4.5% and 5.09%, respectively; compared with Comparative Example 1, all properties of Example 3 are significantly improved. It is worth mentioning that Comparative Example 3 has low viscosity, which is within the processable range, making the best-performing Example 3 practically applicable to road engineering.

[0071] Segregation experiments were used to characterize the storage stability of high-content compounded waste rubber powder modified asphalt. The smaller the difference in softening points between the upper and lower layers after segregation, the better the storage stability. Results are as follows: Figure 1As shown, compared with Comparative Examples 2 and 3 (i.e., single-type rubber powder modified asphalt), Example 3 showed a decrease in softening point difference of 1.85℃ and 2.25℃, respectively. As can be seen from Examples 1 to 3, with the increase of waste nylon tire rubber powder content in the compounded rubber powder, the softening point difference gradually decreased to about 0℃, and the storage stability was greatly improved.

[0072] This invention provides a high-content compound waste rubber powder modified asphalt, which mixes undesulfurized nylon tire waste rubber powder with partially desulfurized rubber powder. Under conventional preparation conditions, this significantly increases the rubber powder content while ensuring good road performance of the modified asphalt. It not only solves the problems of poor compatibility, high viscosity, and easy segregation in high-content ordinary waste rubber powder modified asphalt, but also solves the problem of decreased high-temperature performance of modified asphalt due to the destruction of the cross-linking structure and reduction of molecular weight of desulfurized rubber powder. Compared to traditional low-dosage rubber powder modification of asphalt using a single type and state, using high-dosage compounded rubber powder for asphalt modification offers the following advantages: The desulfurized rubber powder exhibits high surface activity, low molecular weight, and ease of processing. Compared to undesulfurized rubber powder, it dissolves into the base asphalt more quickly and effectively, transforming into a relatively loose linear flocculated structure. This provides space for the remaining undesulfurized rubber powder to swell and develop, allowing it to fully absorb lightweight components and form a better gel film interface with the base asphalt. Furthermore, its cross-linked structure ensures the presence of the rubber core, improving the high-temperature and mechanical properties of the asphalt. The cross-linked network structure of the swollen undesulfurized nylon tire rubber powder enhances the high and low temperature performance of the asphalt; while the desulfurized rubber powder, with its disrupted cross-linked structure, low molecular weight, and ease of processing, dissolves quickly in the base asphalt, and the resulting modified system is stable and difficult to separate. Mixing and compounding these two materials lowers the preparation temperature and time of the modified asphalt, ensuring system stability while improving overall performance. The resulting waste rubber powder modified asphalt has a high softening point, moderate penetration, and good elastic recovery performance; it also has excellent low-temperature toughness, high-temperature stability, fatigue resistance, and processability.

[0073] Therefore, this invention employs the aforementioned high-content compounded waste rubber powder modified asphalt, its preparation method, and its application. Partially desulfurized rubber powder is blended with waste nylon tire rubber powder for asphalt modification. This increases the rubber powder content while simultaneously improving the high and low temperature performance, storage stability, and processing performance of the modified asphalt. The high-content compounded waste rubber powder modified asphalt provided by this invention exhibits excellent comprehensive performance, making it suitable for road engineering. It possesses excellent low-temperature toughness, high-temperature stability, and fatigue resistance. Furthermore, the preparation temperature is low, the preparation time is short, and it allows for the resource utilization of large quantities of waste tires, achieving the recycling of waste tires.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A high-content compounded waste rubber powder modified asphalt, characterized in that, It is composed of the following raw materials in parts by weight: 380-390 parts of base asphalt, 43% of the total mass of waste nylon tire rubber powder and desulfurized rubber powder, 30% of the mass of waste nylon tire rubber powder, and 13% of the mass of desulfurized rubber powder; the waste nylon tire rubber powder is undesulfurized waste nylon tire rubber powder.

2. The high-content compounded waste rubber powder modified asphalt according to claim 1, characterized in that: The particle size of the waste nylon tire rubber powder is 0.2-0.6 mm; the particle size of the desulfurized rubber powder is 0.2-0.6 mm.

3. The method for preparing a high-content compounded waste rubber powder modified asphalt according to any one of claims 1-2, characterized in that, Includes the following steps: Step 1: Mix waste nylon tire rubber powder and desulfurized rubber powder evenly to obtain compound rubber powder, and dry it in an oven; Step 2: The compounded rubber powder obtained in Step 1 is added to the base asphalt for modification, and then shear emulsified to obtain waste rubber powder modified asphalt. The shear emulsification is segmented shear emulsification, which includes a first-stage shear emulsification and a second-stage shear emulsification. The rotation speed of the first-stage shear emulsification is 2000-3000 rpm and the time is 10-15 min. The rotation speed of the second-stage shear emulsification is 4000-5000 rpm and the time is 20-35 min.

4. The method for preparing a high-content compounded waste rubber powder modified asphalt according to claim 3, characterized in that: In step one, the oven drying temperature is 70-80℃, and the drying time is 9-12 hours.

5. The method for preparing a high-content compounded waste rubber powder modified asphalt according to claim 3, characterized in that: In step two, the modification is carried out under stirring conditions. The modification temperature is 190-200℃, the stirring speed is 1000-1300rpm, and the holding time is 50-60min.

6. The method for preparing a high-content compounded waste rubber powder modified asphalt according to claim 3, characterized in that: In step two, the temperature for shear emulsification is 190–200℃, the rotation speed is 2000–5000 rpm, and the time is 30–50 min.

7. The application of waste rubber powder modified asphalt prepared by the preparation method according to any one of claims 3-6 in road engineering.

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