Preparation method of tannin modified rubber powder composite microalgae bio-oil cold patch asphalt

Abstract

The application discloses a preparation method of tannic acid modified rubber powder composite microalgae biological oil cold patching asphalt, and belongs to the technical field of rubber asphalt and asphalt mixture modification. The tannic acid modified rubber powder composite microalgae biological oil cold patching asphalt is prepared from rubber powder modified by 3-aminopropyltrimethoxysilane and tannic acid, and further prepared from the rubber powder to obtain rubber asphalt with high viscoelasticity and excellent deformation resistance. Furthermore, the rubber asphalt is used to prepare a diluent and aggregate from microalgae biological oil to obtain the tannic acid modified rubber powder composite microalgae biological oil cold patching asphalt, and the cold patching asphalt mixture has high initial strength, high forming strength and fast forming time, and solves the problems of poor initial strength, long hardening time and insufficient forming strength of traditional cold patching asphalt mixture.

Description

Technical Field

[0001] This invention belongs to the field of rubber asphalt and asphalt mixture modification technology, specifically relating to a method for preparing tannic acid-modified rubber powder composite microalgae bio-oil cold patch asphalt. Background Technology

[0002] With the development of the automotive industry, the amount of waste tires generated is increasing. Waste tires decompose slowly in the natural environment, and their accumulation leads to environmental pollution and resource waste. Researchers have discovered that adding rubber powder made from waste tires to asphalt creates rubberized asphalt. Rubberized asphalt has strong elastic recovery capabilities, improving road surface resistance to deformation and fatigue cracking; it also exhibits good high and low temperature performance, reducing the asphalt's temperature sensitivity; simultaneously, rubberized asphalt has high viscosity, strong anti-aging and anti-oxidation capabilities; and open-graded or discontinuous-graded rubberized asphalt pavements offer high anti-skid properties, reducing water splashing, improving visibility, and lowering noise, significantly enhancing road safety and comfort.

[0003] However, the high viscosity of rubber asphalt leads to a greater energy requirement during its preparation and application. The poor compatibility between rubber powder and asphalt, coupled with the low storage stability of rubber asphalt, limits the use of large amounts of rubber powder, hindering the full utilization of the excellent properties of rubber asphalt. Furthermore, it necessitates continuous stirring at appropriate temperatures during transportation and storage to prevent segregation. These drawbacks have limited the widespread application of rubber asphalt in practical engineering projects. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing tannic acid-modified rubber powder composite microalgae bio-oil cold-mix asphalt. By first grafting tannic acid onto microwave-activated rubber powder, the inert surface of the rubber powder is successfully transformed into an active surface with hydroxyl and imino groups. Simultaneously, hydrophobic groups are grafted onto the rubber powder surface using these active groups, resulting in the modified product APTMS-TA-RP. The modified product APTMS-TA-RP is then added to the base asphalt to prepare APTMS-TA-RP modified asphalt. Finally, a self-made composite diluent is used to prepare high-performance cold-mix cold-patch modified asphalt. When applied to asphalt pavements, this product can improve the performance of rubber asphalt, enhance the initial strength and molding strength of cold-mix asphalt mixtures, and reduce molding time.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] One of the technical solutions of the present invention is to provide a hydrophobically modified rubber powder, which is a rubber powder (RP) modified by composite of 3-aminopropyltrimethoxysilane (APTMS) and tannic acid (TA).

[0007] The second technical solution of the present invention: a method for preparing the hydrophobic modified rubber powder according to claim 1, comprising the following steps:

[0008] Rubber powder with surface impurities removed was microwave-activated, mixed with 3-aminopropyltrimethoxysilane and tannic acid in a buffer solution, ultrasonically dispersed, and then reacted to obtain hydrophobically modified rubber powder.

[0009] Tannic acid coating, as an organic polymer, exhibits excellent stability and coating properties. Microwave-assisted modification increases both the surface roughness of the rubber powder and the number of active sites on its surface, promoting efficient encapsulation of the polytannic acid self-polymerization film. During the modification process, a core-shell structure can be formed using the rubber powder as the core. Furthermore, hydrophobic groups are grafted onto the tannic acid coating layer through chemical grafting methods such as Michael addition and Schiff base reactions, further forming a hydrophobic protective layer. This process not only preserves the excellent mechanical properties of the rubber powder but also significantly improves its storage stability in asphalt.

[0010] Because rubber powder is an insoluble chemically cross-linked polymer formed by vulcanization and cross-linking, its surface is chemically inert, resulting in poor adhesion between the rubber powder and the asphalt matrix and a lack of bonding sites. Furthermore, rubber powder differs significantly from asphalt molecules in density, molecular weight, and chemical structure, making it prone to sedimentation and segregation during long-term storage. Therefore, grafting hydrophobic groups onto the tannic acid coating layer improves the compatibility between rubber powder and asphalt. Simultaneously, as an oleophilic material, rubber powder can protect the asphalt's anti-aging properties during construction, heating, and paving, further enhancing the stability of the modified asphalt.

[0011] Preferably, the particle size of the rubber powder does not exceed 30 mesh (0.6 mm).

[0012] Preferably, the method for removing impurities from the surface of the rubber powder is soaking in a sodium hydroxide solution; more preferably, the concentration of the sodium hydroxide solution is 1-3 g / 100 mL.

[0013] Preferably, the microwave activation specifically involves irradiating rubber powder with microwaves, wherein the microwave power is 500-1000W and the irradiation time is 1-2 minutes.

[0014] Preferably, the buffer solution is a Tris-HCl buffer solution with a pH of 8.0 to 9.0.

[0015] Preferably, the solid-liquid ratio of the rubber powder to the buffer solution is 1g:(3-10)mL; the volume ratio of the 3-aminopropyltrimethoxysilane to the buffer solution is (1-2):10; and the solid-liquid ratio of the tannic acid to the buffer solution is (1-1.5)g:100mL.

[0016] Preferably, the ultrasonic dispersion time is not less than 15 minutes; the reaction temperature is 25-60°C, and the time is 12-24 hours.

[0017] The third technical solution of the present invention provides a rubber asphalt, the components of which include the above-mentioned hydrophobic modified rubber powder and asphalt, wherein the hydrophobic modified rubber powder accounts for 15-25% of the mass of the asphalt.

[0018] Preferably, the rubber asphalt is obtained by blending the hydrophobic modified rubber powder with the asphalt at a temperature of 150–200°C.

[0019] The fourth technical solution of the present invention provides a cold-mixed and cold-patch modified asphalt, the components of which include the above-mentioned rubber asphalt and a composite diluent; the composite diluent accounts for 25% of the mass of the rubber asphalt; the composite diluent is obtained by compounding 27% by mass of microalgae bio-oil, 48% by mass of diesel oil, 15% by mass of toluene and 10% by mass of acetone.

[0020] The design of cold patch rubber asphalt mixtures needs to consider their strength requirements at different stages, as well as the relationship between workability and strength. The initial strength and molding strength of cold patch mixtures are determined by the cohesiveness and adhesion of the asphalt itself, as well as the internal friction caused by the intercalation and locking between mineral particles after rolling. Therefore, this invention modifies the rubber asphalt to increase its cohesiveness and adhesion.

[0021] Furthermore, selecting the correct diluent is crucial for producing high-quality cold patch mixes. Generally, lower viscosity improves the workability and storage stability of the mix, while higher viscosity helps increase the initial strength after paving and compaction. Therefore, choosing the appropriate diluent is essential. The diluent must have good solubility to ensure the workability of the mix at the repair site and sufficient volatility to restore viscosity and ensure adequate initial strength.

[0022] Therefore, this invention first utilizes hydrophobically modified rubber powder to prepare rubberized asphalt, thereby improving the viscoelasticity and deformation resistance of the rubberized asphalt. Further, it incorporates a microalgae bio-oil composite diluent to prepare high-performance cold-mix / cold-patch modified asphalt. The self-made composite diluent, by introducing microalgae bio-oil, reduces the proportion of diesel fuel added. Furthermore, as a light oil, microalgae bio-oil exhibits excellent solubility in asphalt, effectively reducing its viscosity. The high flash point, high volatility, and environmental friendliness of microalgae bio-oil enhance the safety and practicality of the asphalt diluent. This successfully solves the problems of poor initial strength, long hardening time, and insufficient molding strength inherent in traditional cold-mix / cold-patch asphalt mixtures.

[0023] The beneficial technical effects of the present invention are as follows:

[0024] This invention introduces microwave assistance during the preparation process, enabling tannic acid to better adhere to the surface of rubber powder, rapidly depositing and accumulating on its surface to form a polytannic acid coating layer. This coating layer is stable and durable, and can act as a link to increase the bonding force between thermosetting rubber powder and asphalt. Furthermore, the deposited polytannic acid layer also has functional groups such as hydroxyl and imine groups, providing a large number of active groups for further functionalization. It readily reacts with the amine groups in substances such as 3-aminopropyltrimethoxysilane to undergo Schiff base reactions, further promoting the efficient grafting of hydrophobic functional groups onto the surface of rubber powder.

[0025] This invention significantly improves the compatibility between rubber powder and asphalt, helping the rubber powder to disperse better and more evenly in the asphalt, thereby providing three-dimensional mechanical support and enhancing the elasticity of the asphalt. Simultaneously, the hydrophobic functional groups obtained from the secondary modification of the rubber powder can improve the hydrophobic properties of the asphalt, thus enhancing its resistance to water loss.

[0026] This invention prepares cold patching material by mixing modified rubber powder with a self-made composite diluent, which improves the initial strength and molding strength of cold-mixed asphalt mixture and reduces molding time. Attached Figure Description

[0027] Figure 1 This is a comparison chart of the complex shear modulus of the products obtained in Example 4, Comparative Example 1, and Comparative Example 5.

[0028] Figure 2 This is a comparison chart of the energy storage modulus of the products obtained in Example 5, Comparative Example 2, and Comparative Example 5.

[0029] Figure 3 This is a comparison chart of the loss modulus of the products obtained in Example 6, Comparative Examples 3 and 5.

[0030] Figure 4 This is a comparison diagram of the Kentenberg scattering test results of the products obtained in Example 7 and Comparative Example 6.

[0031] Figure 5 This is a comparison chart of the strength tests of the products obtained in Example 7 and Comparative Example 6. Detailed Implementation

[0032] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.

[0033] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, are also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0034] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar to or equivalent to those described herein may be used in the implementation or testing of this invention.

[0035] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0036] Example 1

[0037] Preparation of hydrophobically modified rubber powder (APTMS-TA-RP):

[0038] (1) Use a 30-mesh sieve to separate impurities and large particles in the rubber powder, so that the rubber powder has a uniform particle size distribution.

[0039] (2) Soak the rubber powder after sieving in step (1) in a NaOH solution with a concentration of 1 g / 100 mL for 25 min to remove insoluble impurities (zinc stearate) on the surface of the rubber powder. After soaking, rinse with deionized water and anhydrous ethanol, and place the rubber powder in an oven to dry to remove moisture and volatiles. The drying temperature is controlled at 60℃ and the drying time is 2 h.

[0040] (3) Place the dried rubber powder from step (2) evenly in a ceramic dish and place it in a microwave oven. Adjust the microwave power to 500W and microwave for 1 minute to ensure that the rubber powder is evenly and fully irradiated in order to produce microwave-activated rubber powder.

[0041] (4) Collect 10g of microwave-activated rubber powder obtained in step (3) and place it in 100mL of Tris-HCl buffer. Add 1g of tannic acid and 10mL of APTMS, and sonicate in an ultrasonic cell disruptor for 15min at a controlled temperature of 60℃. After completion, stir at 350rpm for 12h under a 60℃ water bath. The Tris-HCl buffer is prepared by dissolving 0.6057g of Tris in 100mL of water and titrating with 1M HCl solution to pH=8.0.

[0042] (5) After the reaction in step (4) is completed, filter the product, wash it repeatedly with anhydrous ethanol and water, and dry it in an oven at 60°C for 12 hours to obtain the target product APTMS-TA-RP.

[0043] Example 2

[0044] Preparation of hydrophobically modified rubber powder (APTMS-TA-RP):

[0045] (1) Use a 30-mesh sieve to separate impurities and large particles in the rubber powder, so that the rubber powder has a uniform particle size distribution.

[0046] (2) Soak the rubber powder after sieving in step (1) in a NaOH solution with a concentration of 2g / 100mL for 25min to remove insoluble impurities (zinc stearate) on the surface of the rubber powder. After soaking, rinse with deionized water and anhydrous ethanol, and place the rubber powder in an oven to dry to remove moisture and volatiles. The drying temperature is controlled at 60℃ and the drying time is 2h.

[0047] (3) Place the dried rubber powder from step (2) evenly in a ceramic dish and place it in a microwave oven. Adjust the microwave power to 750W and microwave for 1.5 minutes to ensure that the rubber powder is evenly and fully irradiated in order to produce microwave-activated rubber powder.

[0048] (4) Collect 10g of microwave-activated rubber powder obtained in step (3) and place it in 100mL of Tris-HCl buffer. Add 1.25g of tannic acid and 15mL of APTMS. Sonicate in an ultrasonic cell disruptor for 15min, with the ultrasonic temperature controlled at 60℃. After completion, stir at 350rpm for 12h under 60℃ water bath heating. The Tris-HCl buffer is prepared by dissolving 0.6057g of Tris in 100mL of water and titrating with 1M HCl solution to pH=8.5.

[0049] (5) After the reaction in step (4) is completed, filter the product, wash it repeatedly with anhydrous ethanol and water, and dry it in an oven at 60°C for 12 hours to obtain the target product APTMS-TA-RP.

[0050] Example 3

[0051] Preparation of hydrophobically modified rubber powder (APTMS-TA-RP):

[0052] (1) Use a 30-mesh sieve to separate impurities and large particles in the rubber powder, so that the rubber powder has a uniform particle size distribution.

[0053] (2) Soak the rubber powder after sieving in step (1) in a NaOH solution with a concentration of 3g / 100mL for 25min to remove insoluble impurities (zinc stearate) on the surface of the rubber powder. After soaking, rinse with deionized water and anhydrous ethanol, and place the rubber powder in an oven to dry to remove moisture and volatiles. The drying temperature is controlled at 60℃ and the drying time is 2h.

[0054] (3) Place the dried rubber powder from step (2) evenly in a ceramic dish and place it in a microwave oven. Adjust the microwave power to 1000W and microwave for 2 minutes to ensure that the rubber powder is evenly and fully irradiated in order to produce microwave-activated rubber powder.

[0055] (4) Collect 10g of microwave-activated rubber powder obtained in step (3) and place it in 100mL of Tris-HCl buffer. Add 1.5g of tannic acid and 20mL of APTMS. Sonicate in an ultrasonic cell disruptor for 15min, with the ultrasonic temperature controlled at 60℃. After completion, stir at 350rpm for 12h under 60℃ water bath heating. The Tris-HCl buffer is prepared by dissolving 0.6057g of Tris in 100mL of water and titrating with 1M HCl solution to pH=9.0.

[0056] (5) After the reaction in step (4) is completed, filter the product, wash it repeatedly with anhydrous ethanol and water, and dry it in an oven at 60°C for 12 hours to obtain the target product APTMS-TA-RP.

[0057] Example 4

[0058] Preparation of rubber asphalt:

[0059] Weigh 200g of SK-70A asphalt and dry it in an oven at 135℃ for 2 hours to remove excess moisture. Add the APTMS-TA-RP obtained in Example 1 to the asphalt and keep the temperature constant at 165℃. Disperse the asphalt in a high-speed shear machine at 400rpm for 2 hours to ensure that the modifier is evenly dispersed in the asphalt, thus obtaining rubber asphalt. The amount of APTMS-TA-RP added is 15% of the total mass of the asphalt.

[0060] Example 5

[0061] Preparation of rubber asphalt:

[0062] Weigh 200g of SK-70A asphalt and dry it in an oven at 135℃ for 2 hours to remove excess moisture. Add the APTMS-TA-RP obtained in Example 2 into the asphalt and keep the temperature constant at 175℃. Disperse the asphalt in a high-speed shear machine at 400rpm for 2 hours to ensure that the modifier is evenly dispersed in the asphalt, thus obtaining rubber asphalt. The amount of APTMS-TA-RP added is 20% of the total mass of the asphalt.

[0063] Example 6

[0064] Preparation of rubber asphalt:

[0065] Weigh 200g of SK-70A asphalt and dry it in an oven at 135℃ for 2 hours to remove excess moisture. Add the APTMS-TA-RP obtained in Example 3 into the asphalt and keep it at a constant temperature of 185℃. Disperse it in a high-speed shear machine at 400rpm for 2 hours to make the modifier evenly dispersed in the asphalt, thus obtaining rubber asphalt. The amount of APTMS-TA-RP added is 25% of the total mass of asphalt.

[0066] Example 7

[0067] Preparation of cold-mix and cold-patched modified asphalt mixtures:

[0068] A composite diluent was prepared by mixing 27% by mass of microalgae bio-oil, 48% by mass of diesel oil, 15% by mass of toluene, and 10% by mass of acetone. The rubber asphalt prepared in Example 4 was mixed with the self-made composite diluent at a concentration of 25% of the rubber asphalt mass. A fixed amount of aggregate was then added to obtain a cold-mix modified asphalt mixture (APTMS-TA-RP mixture).

[0069] Comparative Example 1

[0070] Preparation of rubber asphalt:

[0071] Weigh 200g of SK-70A asphalt and dry it in an oven at 135℃ for 2 hours to remove excess moisture. Add the rubber powder (RP) that has been purified with NaOH in step (2) of Example 1 to the asphalt. Keep the temperature constant at 165℃ and disperse the fibers in a high-speed shear machine at 400rpm for 2 hours to make the modifier evenly dispersed in the asphalt, thus obtaining RP modified asphalt. The amount of RP added is 15% of the total mass of asphalt.

[0072] Comparative Example 2

[0073] Preparation of rubber asphalt:

[0074] Weigh 200g of SK-70A asphalt and dry it in an oven at 135℃ for 2 hours to remove excess moisture. Add the rubber powder (RP) that has been purified with NaOH in step (2) of Example 2 to the asphalt. Keep the temperature constant at 175℃ and disperse it in a high-speed shear machine at 400rpm for 2 hours to make the modifier evenly dispersed in the asphalt, thus obtaining RP modified asphalt. The amount of RP added is 20% of the total mass of asphalt.

[0075] Comparative Example 3

[0076] Preparation of rubber asphalt:

[0077] Weigh 200g of SK-70A asphalt and dry it in an oven at 135℃ for 2 hours to remove excess moisture. Add the rubber powder (RP) that has been purified with NaOH in step (2) of Example 3 to the asphalt. Keep the temperature constant at 185℃ and disperse it in a high-speed shear machine at 400rpm for 2 hours to make the modifier evenly dispersed in the asphalt, thus obtaining RP modified asphalt. The amount of RP added is 25% of the total mass of asphalt.

[0078] Comparative Example 4

[0079] Preparation of hydrophobically modified rubber powder (APTMS-TA-RP-1):

[0080] Compared with Example 1, the only difference is that the microwave activation step (2) is omitted, and the rubber powder after impurity removal is directly modified with tannic acid and APTMS.

[0081] Comparative Example 5

[0082] Preparation of APTMS-TA-RP-1 rubber asphalt:

[0083] Compared with Example 4, the only difference is that the APTMS-TA-RP prepared in Example 1 is replaced with the APTMS-TA-RP-1 modified bitumen prepared in Comparative Example 4.

[0084] Comparative Example 6

[0085] Preparation of cold-mix and cold-patched modified asphalt mixtures:

[0086] The rubber asphalt prepared in Example 4 was mixed with diesel (diluent), with the amount of diesel added being 25% of the mass of the rubber asphalt. A fixed amount of aggregate was added to obtain cold-mix cold-patch modified asphalt (APTMS-TA-RP-2 mixture).

[0087] DSR Test:

[0088] DSR tests were performed on the rubber asphalt prepared in Examples 4-6, Comparative Examples 1-3, and Comparative Example 5. Specifically, 1.0 g of rubber asphalt was poured into the center of a test plate with a diameter of 25 mm. The test plate was moved to compress the rubber asphalt between the two test plates. The specimen trimmer was heated to correct excess asphalt around the perimeter, and then the gap was adjusted to a test gap of 1 mm. When the temperature reached equilibrium, the equipment automatically conducted the test at a frequency of 10 rad / s and the selected stress target value. Recording and calculation were completed by the data acquisition system.

[0089] DSR test results:

[0090] Figure 1 This is a comparison graph showing the complex shear modulus of the products obtained in Example 4, Comparative Examples 1 and 5. From... Figure 1 It can be seen that the complex shear modulus G of the two modified asphalts* At the same temperature, the complex shear modulus G of the APTMS-TA-RP modified asphalt in Example 4 * All of them are greater than the complex shear modulus G of the RP-modified asphalt in Comparative Example 1. * The results showed that RP modified with tannic acid and 3-aminopropyltrimethoxysilane improved the deformation resistance of asphalt when added to it.

[0091] Figure 2 This is a comparison chart of the storage modulus of the products obtained in Example 5, Comparative Examples 2 and 5. From... Figure 2 It can be seen that, at the same temperature, the storage modulus G' of APTMS-TA-RP modified asphalt is greater than that of RP modified asphalt, indicating that the elastic properties of APTMS-TA-RP modified asphalt are enhanced.

[0092] Figure 3 This is a comparison chart of the loss modulus of the products obtained in Example 6, Comparative Examples 3 and 5. From... Figure 3 It can be seen that at the same temperature, the loss modulus G” of APTMS-TA-RP modified asphalt is greater than that of RP modified asphalt, indicating that the viscosity properties of APTMS-TA-RP modified asphalt are enhanced.

[0093] Combination Figures 1-3 It can be seen that the complex shear modulus G of APTMS-TA-RP modified asphalt is... * The storage modulus G' and loss modulus G" are both greater than those of RP modified asphalt. This indicates that while the viscosity of APTMS-TA-RP modified asphalt is improved, its elasticity is also improved to a certain extent, proving that the addition of hydrophobically modified rubber powder to asphalt can effectively improve the viscoelastic properties and deformation resistance of asphalt.

[0094] Kentucky scattering experiment:

[0095] Figure 4 This is a comparison diagram of the Kentucky scattering test results of the products obtained in Example 7 and Comparative Example 6. Cold-mix cold-patch asphalt was prepared using rubber asphalt, and the initial cohesion of the cold-mix cold-patch asphalt under low-temperature conditions was evaluated using the Kentucky scattering test. Therefore, in addition to the test temperatures specified in the standard, two additional temperatures, namely 5°C and 0°C, were added.

[0096] according to Figure 4It can be seen that at a temperature of 20℃, the APTMS-TA-RP mixture has the lowest scattering loss compared to the RP mixture. As the temperature decreases, the scattering loss of the APTMS-TA-RP mixture is less than that of the APTMS-TA-RP-2 mixture, and the APTMS-TA-RP mixture exhibits superior adhesion at room temperature. Within the temperature range of 0–5℃, the scattering loss of the APTMS-TA-RP-2 mixture increases significantly because the evaporation rate of the diluent slows down under these conditions, leading to a decrease in the performance of the cold-mix / cold-patch mixture. The slower reduction in scattering loss for the APTMS-TA-RP mixture indicates that the self-made diluent of this invention has better volatility performance at low temperatures.

[0097] Strength test of cold-mixed and cold-pressed aggregate:

[0098] Figure 5 This is a comparison chart of the strength tests of the products obtained in Example 7 and Comparative Example 6. From... Figure 5 As can be seen, the APTMS-TA-RP mixture exhibits the highest initial strength. Under room temperature curing conditions, the molding strength of the APTMS-TA-RP mixture exceeds 5 kN. Compared to the APTMS-TA-RP-2 mixture, the APTMS-TA-RP mixture has a faster molding time. Furthermore, the diluent used in the APTMS-TA-RP mixture has excellent volatility, resulting in faster viscosity recovery of the diluted asphalt, thus allowing the asphalt to function as a standard binder more quickly. Therefore, in practical engineering projects, traffic can be opened more rapidly.

[0099] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A rubber asphalt, characterized in that, The preparation steps of the rubber asphalt are: 200g of SK-70A asphalt is weighed and dried in a 135℃ oven for 2h to remove excess moisture, the hydrophobic modified rubber powder is added into the asphalt, kept at 165℃, and dispersed in a high-speed shearing machine at 400rpm for 2h to make the hydrophobic modified rubber powder uniformly dispersed in the asphalt, i.e. the rubber asphalt is obtained; the addition amount of the hydrophobic modified rubber powder is 15% of the total mass of the asphalt; The preparation steps of the hydrophobic modified rubber powder are: (1) the impurities and large particles in the rubber powder are separated by using a 30-mesh sieve to make the particle size distribution of the rubber powder uniform; (2) the rubber powder sieved in step (1) is soaked in a 1g / 100mL NaOH solution for 25min to remove the insoluble impurities on the surface of the rubber powder, and then washed with deionized water and anhydrous ethanol, and dried in an oven to remove water and volatile matter, with the drying temperature controlled at 60℃ and the drying time being 2h; (3) the dried rubber powder in step (2) is uniformly placed in a porcelain dish and placed in a microwave oven, with the microwave power adjusted to 500W and the microwave treatment time being 1min to ensure that the rubber powder is uniformly and fully irradiated to produce microwave-activated rubber powder; (4) 10g of the microwave-activated rubber powder obtained in step (3) is collected and placed in 100mL of Tris-HCl buffer solution, 1g of tannic acid and 10mL of 3-aminopropyltrimethoxysilane are added, and ultrasonic treatment is performed in an ultrasonic cell disruptor for 15min, with the ultrasonic temperature controlled at 60℃, and after completion, stirring is performed at 350rpm for 12h in a 60℃ water bath, wherein the Tris-HCl buffer solution is prepared by dissolving 0.6057g of Tris in 100mL of water and titrating with 1M HCl solution to pH=8.0; (5) the product after reaction in step (4) is filtered, washed repeatedly with anhydrous ethanol and water, and dried in a 60℃ oven for 12h to obtain the hydrophobic modified rubber powder.

2. A cold-mix cold-patch modified asphalt, characterized in that, The components are the rubber asphalt of claim 1 and a composite diluent; the composite diluent accounts for 25% of the mass of the rubber asphalt; and the composite diluent is compounded from 27% of microalgae bio-oil, 48% of diesel oil, 15% of toluene and 10% of acetone by mass percentage.

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