High-dosage compound waste rubber powder modified asphalt as well as preparation method and application thereof

Abstract

The invention discloses high-dosage compound waste rubber powder modified asphalt as well as a preparation method and application thereof. The modified asphalt is prepared from the following raw materials in parts by weight: 360 to 410 parts of matrix asphalt, 0 to 168 parts of waste nylon tire rubber powder and 0 to 168 parts of desulfurized rubber powder, and the ratio of the additive amount of the desulfurized rubber powder to the additive amount of the waste nylon tire rubber powder is 0.30 to 0.77. The invention also discloses a preparation method of the high-dosage compound waste rubber powder modified asphalt. According to the preparation method of the high-mixing-amount compound waste rubber powder modified asphalt, the partially desulfurized rubber powder and the waste nylon tire rubber powder are blended and compounded for asphalt modification, so that the mixing amount of the rubber powder is greatly increased, and meanwhile, the high and low temperature performance, the storage stability performance and the processability of the modified asphalt are all at a relatively high level.

Description

Technical Field

[0001] The invention relates to the technical field of asphalt modification, and in particular to a high-dosage compounded waste rubber powder modified asphalt and a preparation method and application thereof. Background Art

[0002] With the gradual improvement of living standards and the rapid development of the logistics industry, the number of cars in my country has increased year by year. The increase in the number of vehicles has driven the development of the automobile tire industry, but the continuous consumption and wear of automobile tires have also generated a lot of waste tire garbage. The annual waste tires increase at a rate of 8% to 10%, but the recycling rate is only about 50%. Reusing waste tires as resources, expanding the recycling channels of waste tires, and reducing resource waste are one of the problems that need to be solved at this stage.

[0003] On the other hand, the development of the automobile industry has also led to a gradual increase in road transportation pressure, and the demand for road asphalt and pavement performance have also increased. Studies have shown that compared with SBS modified asphalt, the use of widely available and inexpensive waste rubber powder to modify asphalt can give it good high and low temperature performance, while also recycling waste automobile tires, which has good environmental benefits. However, the existing rubber powder content in rubber asphalt is about 20%. With the increase in the content, the rubber powder modified asphalt will have a series of problems such as high viscosity, easy segregation, and difficult construction of the mixture, which has brought huge difficulties to engineering units and limited the increase in the content of rubber powder and the further improvement of the performance of rubber asphalt pavement.

[0004] In order to solve the problem that it is difficult to increase the amount of rubber powder in waste rubber powder modified asphalt, the current solution is to desulfurize, modify or treat the ordinary rubber powder with a variety of activators, accompanied by long-term high-temperature swelling and high-speed shearing and other process conditions. However, this often causes the rubber molecules to change from a network structure to a branched structure with a smaller molecular weight, destroying the cross-linking structure and cracking the polymer main chain. Although it can increase the amount of waste rubber powder and reduce the construction viscosity, the basic performance of the prepared modified asphalt is far inferior to that of ordinary waste rubber powder modified asphalt.

[0005] Therefore, it is urgent to propose a preparation method and application of high-performance asphalt modified with a high amount of waste rubber powder. Summary of the invention

[0006] The purpose of the present invention is to provide a high-dosage compounded waste rubber powder modified asphalt and its preparation method and application, and the partially desulfurized rubber powder is mixed and compounded with waste nylon tire rubber powder and used for asphalt modification, which greatly increases the rubber powder dosage while making the high and low temperature performance, storage stability and processing performance of the modified asphalt at a high level.

[0007] To achieve the above-mentioned purpose, the present invention provides a high-dosage compounded 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, and the compounding ratio of the desulfurized rubber powder to the 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 base asphalt is 380-390 parts, the total mass of waste nylon tire rubber powder and desulfurized rubber powder is 43% of the amount of base asphalt added, the mass of waste nylon tire rubber powder is 30% of the amount of base asphalt added, and the mass of desulfurized rubber powder is 13% of the amount of base asphalt added.

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

[0011] Step 1: Evenly mix the waste nylon tire rubber powder and the desulfurized rubber powder to obtain the compound rubber powder, and put it into an oven for drying;

[0012] Step 2: Add the compound rubber powder obtained in step 1 into the base asphalt to modify it, and then shear and emulsify it to obtain waste rubber powder modified asphalt.

[0013] Preferably, in step 1, the oven drying temperature is 70-80° C., and the drying time is 9-12 hours.

[0014] Preferably, in step 2, the modification is carried out under stirring conditions, the modification temperature is 190-200° C., the stirring speed is 1000-1300 rpm, and the insulation time is 50-60 min.

[0015] Preferably, in step 2, the shear emulsification temperature is 190-200° C., the rotation speed is 2000-5000 rpm, and the time is 30-50 min.

[0016] Preferably, in step 2, the shear emulsification is segmented shear emulsification, which includes a first-stage shear emulsification and a second-stage shear emulsification, wherein 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-dosage compounded waste rubber powder modified asphalt, and application of the waste rubber powder modified asphalt in road engineering.

[0018] The advantages and positive effects of the high-dosage compounded waste rubber powder modified asphalt and its preparation method and application described in the present invention are:

[0019] 1. The present invention mixes undesulfurized nylon tire waste rubber powder and partially desulfurized rubber powder, which greatly increases the rubber powder content under conventional preparation conditions and ensures good road performance of the modified asphalt. It not only solves the problems of poor compatibility, high viscosity, and easy segregation of asphalt modified with high-content ordinary waste rubber powder, but also solves the problem of decreased high-temperature performance of modified asphalt due to the destruction of the cross-linking structure of the desulfurized rubber powder and the reduction of the molecular weight.

[0020] 2. The cross-linked network structure of the undesulfurized nylon tire rubber powder after swelling enhances the high and low temperature performance of the asphalt; while the cross-linked structure of the desulfurized rubber powder is destroyed, the molecular weight is small and easy to process, the solubility speed with the matrix asphalt is fast, and the modified system formed is stable and not easy to separate. After mixing and compounding the two, the preparation temperature and preparation time of the modified asphalt are reduced, and the stability of the system is ensured while improving various comprehensive performances, so that the obtained 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. The present invention ensures that the swelling and degradation degree of desulfurized rubber powder and non-desulfurized rubber powder in the matrix asphalt are optimal by controlling the rotation speed, temperature and time of the stirring and shearing emulsification stages, so that the modified asphalt has good basic road performance at a high rubber powder content while having the advantages of low viscosity and high storage stability.

[0022] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The storage stability performance diagrams of Examples 1 to 3 of the present invention and Comparative Examples 2 to 3; DETAILED DESCRIPTION

[0024] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0025] Unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. Unless otherwise defined, the materials used in the present invention are all commercially available.

[0026] A high-dosage compounded waste rubber powder modified asphalt includes 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 is 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 desulfurized rubber powder before desulfurization). By selecting rubber powder with appropriate particle size, the performance of modified asphalt can be guaranteed to be optimal. Rubber powder with too large particle size will increase the viscosity of modified asphalt after swelling, and rubber powder with too small particle size will make the performance of modified asphalt insufficient.

[0028] The base asphalt is 380-390 parts, the total mass of waste nylon tire rubber powder and desulfurized rubber powder is 43% of the base asphalt addition, the mass of waste nylon tire rubber powder is 30% of the base asphalt addition, and the mass of desulfurized rubber powder is 13% of the base asphalt addition. Selecting the appropriate number of waste nylon tire rubber powder can make the high-temperature stability of the modified asphalt reach the optimal level. Different numbers of waste nylon tire rubber powder have different modification effects on the base asphalt. As the number of parts increases, the high-temperature performance of the modified asphalt will increase. However, since the waste nylon tire rubber powder maintains an undesulfurized cross-linked structure and has very few surface active groups, using too many parts will not be compatible with the base asphalt, and problems such as high viscosity, easy segregation, and reduced conventional performance will occur. Selecting the appropriate number of desulfurized rubber powder can reduce the viscosity of the modified asphalt and increase the stability of the system. The main chain structure and cross-linking structure of the desulfurized rubber powder are destroyed, and the molecular weight is small. Excessive parts will seriously reduce 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 dosage is 43%, the compounding ratio K of desulfurized rubber powder and waste nylon tire rubber powder is 0.30-0.77, preferably 0.30-0.54, and more preferably 0.30-0.31.

[0030] The compounding ratio K of desulfurized rubber powder and waste nylon tire rubber powder is calculated according to the following formula: A×43%×K=A×DR. (A: base asphalt mass, K: compounding ratio, DR: desulfurized rubber percentage content). Taking 13% desulfurized rubber powder + 30% waste nylon tire rubber powder as an example, if the total amount of rubber powder is confirmed to be 43%, if you want to calculate the compounding ratio of desulfurized rubber powder and nylon rubber powder in this formula, you only need to substitute the base asphalt mass and the percentage content of desulfurized rubber powder in the formula into the formula.

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

[0032] Step 1: Evenly mix the waste nylon tire rubber powder and the desulfurized rubber powder to obtain the compound rubber powder, and put it into an oven for drying;

[0033] Step 2: Add the compound rubber powder obtained in step 1 into the base asphalt to modify it, and then shear and emulsify it to obtain waste rubber powder modified asphalt.

[0034] In step 1, the oven drying temperature is 70-80° C. and the drying time is 9-12 hours.

[0035] In step 2, the modification is carried out under stirring conditions, the modification temperature is 190-200°C, the stirring speed is 1000-1300rpm, and the insulation time is 50-60min. If the stirring temperature is too low and the stirring time is too short, the rubber powder will not be able to fully absorb the light components in the asphalt, the swelling is incomplete, and the performance of the modified asphalt is poor.

[0036] In step 2, the shear emulsification temperature is 190-200° C., the rotation speed is 2000-5000 rpm, and the time is 30-50 min.

[0037] In step 2, the shear emulsification is segmented shear emulsification, which includes one-stage shear emulsification and two-stage shear emulsification. The speed of the first-stage shear emulsification is 2000-3000rpm, and the time is 10-15min; the speed of the second-stage shear emulsification is 4000-5000rpm, and the time is 20-35min. When performing shear emulsification, if the time is too short or the temperature is too low, the viscosity of the modified asphalt cannot be reduced in this process. If the speed is too fast, the rubber powder will be excessively sheared and degraded, and the performance of the modified asphalt will be poor.

[0038] A method for preparing high-dosage compounded waste rubber powder modified asphalt, and its application 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 the road surface, and uses solid waste materials as raw materials, which is low-cost and green and environmentally friendly, with significant economic and social benefits.

[0039] Example 1

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

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

[0042] (1) The waste nylon tire rubber powder and desulfurized rubber powder of the above mass are mixed evenly to obtain a composite rubber powder, which is washed with anhydrous ethanol until the solution is clear and transparent, and then placed in an oven and dried at 70°C for 12 hours.

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

[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°C for 10 minutes and a rotation speed of 2000-2500 rpm; then the temperature is controlled at 190-195°C, the rotation speed is increased to 5000 rpm, and sheared and emulsified for 35 minutes to obtain a composite waste rubber powder modified asphalt.

[0045] Example 2

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

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

[0048] (1) The waste nylon tire rubber powder and desulfurized rubber powder of the above mass are mixed evenly to obtain a composite rubber powder, which is washed with anhydrous ethanol until the solution is clear and transparent, and then placed in an oven and dried at 70°C for 12 hours.

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

[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°C for 10 minutes and a rotation speed of 2000-2500 rpm; then the temperature is controlled at 190-195°C, the rotation speed is increased to 5000 rpm, and sheared and emulsified for 35 minutes to obtain a composite waste rubber powder modified asphalt.

[0051] Example 3

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

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

[0054] (1) The waste nylon tire rubber powder and desulfurized rubber powder of the above mass are mixed evenly to obtain a composite rubber powder, which is washed with anhydrous ethanol until the solution is clear and transparent, and then placed in an oven and dried at 70°C for 12 hours.

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

[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°C for 10 minutes and a rotation speed of 2000-2500 rpm; then the temperature is controlled at 190-195°C, the rotation speed is increased to 5000 rpm, and sheared and emulsified for 35 minutes to obtain a composite waste rubber powder modified asphalt.

[0057] Comparative Example 1

[0058] Matrix asphalt No. 90 390g.

[0059] Comparative Example 2

[0060] A method for preparing high-dosage waste rubber powder modified asphalt comprises the following steps: washing 167.7g of desulfurized rubber powder with anhydrous ethanol, drying at 70°C for 12h, dispersing the dried rubber powder and base asphalt for 55-60min using a high-speed stirring mixer at a temperature of 190-195°C and a stirring rate of 1100-1200rpm. After mixing and modification, the obtained mixture is sheared and emulsified in a high-speed shear emulsifier at a temperature of 190-195°C for 10min at a speed of 2000-2500rpm; then the temperature is controlled at 190-195°C, the speed is increased to 5000rpm, and the shearing and emulsification is performed for 35min to obtain waste rubber powder modified asphalt.

[0061] Comparative Example 3

[0062] A method for preparing high-dosage waste rubber powder modified asphalt comprises the following steps: 167.7 g of 40-mesh waste nylon tire rubber powder is washed with anhydrous ethanol, dried at 70°C for 12 hours, and the dried rubber powder and base asphalt are dispersed and modified for 55 to 60 minutes by a high-speed stirring mixer at a temperature of 190 to 195°C and a stirring rate of 1100 to 1200 rpm. After mixing and modification, the obtained mixture is sheared and emulsified in a high-speed shear emulsifier at a temperature of 190 to 195°C for 10 minutes at a rotation speed of 2000 to 2500 rpm; then the temperature is controlled at 190 to 195°C, the rotation speed is increased to 5000 rpm, and the shearing and emulsification is performed for 35 minutes to obtain the waste rubber powder modified asphalt.

[0063] The dosage of each component in Examples 1 to 3 and Comparative Examples 1 to 3 is 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 matrix asphalt is No. 90 asphalt; the equipment used is a high-speed stirring mixer and a high-speed shearing dispersing emulsifier. The rubber powder used in Comparative Example 2 is pure desulfurized rubber powder, and its addition amount accounts for 43% of the matrix 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 matrix asphalt. In Examples 1 to 3, under the condition that the total amount of waste nylon tire rubber powder and desulfurized rubber powder is 43% of the matrix asphalt, the two rubber powders are compounded, and the content of waste nylon tire rubber powder is continuously increased to seek the best performance. When the best performance is achieved, the mass of waste nylon tire rubber powder is 30% of the amount of matrix asphalt added, and the mass of desulfurized rubber powder is 13% of the amount of matrix asphalt added.

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

[0068] Table 2

[0069]

[0070] According to Table 2, for high-dosage compounded waste rubber powder modified asphalt, as the proportion of waste nylon tire rubber powder (that is, undesulfurized rubber powder) in the compounded rubber powder increases, its low-temperature toughness is improved to a certain extent; high-temperature stability is significantly improved; elastic recovery and needle penetration indexes can continue to maintain a good level, and at the same time, the low viscosity of the blended rubber powder modified asphalt also enables it to have good processing and road application performance. In Examples 1-3, the compounding 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 is increased by 41.29% and 5.50%, respectively, and the softening point is increased by 6.12% and 7.11%, respectively; compared with Examples 1 and 2, the ductility of Example 3 is increased by 39.24% and 22.44%, respectively, and the softening point is increased by 4.5% and 5.09%, respectively; compared with Comparative Example 1, the various properties of Example 3 are greatly improved. It is worth mentioning that comparative example 3 has low viscosity and is within the processable range, so that example 3 with the best performance can be actually applied to road engineering.

[0071] Segregation experiments were used to characterize the storage stability of high-content composite waste rubber powder modified asphalt. The smaller the difference between the upper and lower softening points after segregation, the better the storage stability. Figure 1As shown, compared with Comparative Examples 2 and 3 (i.e., single type of rubber powder modified asphalt), the softening point difference of Example 3 is reduced by 1.85°C and 2.25°C respectively. From Examples 1 to 3, it can be seen that with the increase of the content of waste nylon tire rubber powder in the compound rubber powder, the softening point difference gradually decreases to about 0°C, and the storage stability performance is greatly improved.

[0072] The present invention provides a high-dosage compounded waste rubber powder modified asphalt, which mixes undesulfurized nylon tire waste rubber powder and partially desulfurized rubber powder for use, greatly improves the rubber powder dosage under conventional preparation conditions and ensures good road performance of the modified asphalt, not only solves the problems of poor compatibility, high viscosity, easy segregation, etc. of high-dosage common waste rubber powder modified asphalt, but also solves the problem of reduced high-temperature performance of the modified asphalt due to the destruction of the cross-linking structure of the desulfurized rubber powder and the reduction of the molecular weight. Compared with the traditional single-type, single-state low-content rubber powder modified asphalt, the high-content compounded rubber powder is used to modify asphalt. The compounded rubber powder has the following advantages in modified asphalt: the desulfurized rubber powder has high surface activity, small molecular weight, and easy processing. Compared with the undesulfurized rubber powder, it can be dissolved into the matrix asphalt faster and better to transform into a relatively loose linear flocculation structure, which provides space for the remaining undesulfurized rubber powder to swell, so that the undesulfurized rubber powder can fully absorb the light components for swelling, forming a better gel film interface layer with the matrix asphalt, and its cross-linked structure can ensure the existence of the rubber core and improve the high-temperature performance and mechanical properties of the asphalt. The cross-linked network structure of the undesulfurized nylon tire rubber powder after swelling enhances the high and low temperature performance of the asphalt; while the cross-linked structure of the desulfurized rubber powder is destroyed, the molecular weight is small and easy to process, the dissolution speed with the matrix asphalt is fast, and the modified system formed is stable and not easy to separate. After mixing and compounding the two, the preparation temperature and time of the modified asphalt are reduced, ensuring the stability of the system while improving various comprehensive properties. The obtained waste rubber powder modified asphalt has a high softening point, moderate needle penetration and good elastic recovery performance; it has excellent low-temperature toughness, high-temperature stability, fatigue resistance and processability.

[0073] Therefore, the present invention adopts the above-mentioned high-dosage compounded waste rubber powder modified asphalt and its preparation method and application, and mixes and compounds the partially desulfurized rubber powder with waste nylon tire rubber powder for asphalt modification, while increasing the rubber powder dosage, the high and low temperature performance, storage stability and processing performance of the modified asphalt are all at a high level. The high-dosage compounded waste rubber powder modified asphalt provided by the present invention has excellent comprehensive performance, can be used for road engineering, and has excellent low temperature toughness, high temperature stability and fatigue resistance. In addition, the preparation temperature is low, the preparation time is short, and a large number of waste tires can be utilized as resources to achieve the recycling of waste tires.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A high-dosage compounded waste rubber powder modified asphalt, characterized in that: The invention 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 compounding ratio of the desulfurized rubber powder to the waste nylon tire rubber powder is 0.30-0.

77.

2. The high-dosage 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 to 0.6 mm; the particle size of the desulfurized rubber powder is 0.2 to 0.6 mm.

3. The high-dosage compounded waste rubber powder modified asphalt according to claim 1, characterized in that: The matrix asphalt is 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.

4. The method for preparing a high-dosage composite waste rubber powder modified asphalt according to any one of claims 1 to 3, characterized in that: The steps include: Step 1: Evenly mix the waste nylon tire rubber powder and the desulfurized rubber powder to obtain the compound rubber powder, and put it into an oven for drying; Step 2: Add the compound rubber powder obtained in step 1 into the base asphalt to modify it, and then shear and emulsify it to obtain waste rubber powder modified asphalt.

5. The method for preparing a high-dosage composite waste rubber powder modified asphalt according to claim 4, characterized in that: In step 1, the oven drying temperature is 70-80° C. and the drying time is 9-12 hours.

6. The method for preparing a high-dosage composite waste rubber powder modified asphalt according to claim 4, characterized in that: In step 2, the modification is carried out under stirring conditions, the modification temperature is 190-200° C., the stirring speed is 1000-1300 rpm, and the insulation time is 50-60 min.

7. The method for preparing a high-dosage compounded waste rubber powder modified asphalt according to claim 4, characterized in that: In step 2, the shear emulsification temperature is 190-200° C., the rotation speed is 2000-5000 rpm, and the time is 30-50 min.

8. The method for preparing a high-dosage composite waste rubber powder modified asphalt according to claim 4, characterized in that: In step 2, the shear emulsification is segmented shear emulsification, which includes one-stage shear emulsification and two-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.

9. Use of the waste rubber powder modified asphalt prepared according to the preparation method according to any one of claims 4 to 8 in road engineering.

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