Method for modifying asphalt by desulfurizing waste rubber powder through ternary eutectic solvent

Abstract

The invention discloses a method for modifying asphalt by desulfurizing waste rubber powder through a ternary eutectic solvent, and belongs to the technical field of preparation of modified asphalt. The invention aims to solve the problem that a safe and rapid desulfurization method for destroying the cross-linked structure of the waste rubber powder, enhancing the interaction between the waste rubber powder and asphalt and improving the storage stability of the waste rubber powder modified asphalt is lacked in the prior art. The method comprises the following steps: 1, preparing a ternary eutectic solvent; 2, desulfurizing the waste rubber powder by using a ternary eutectic solvent; and 3, preparing the modified asphalt. The method is used for the ternary eutectic solvent desulfurization waste rubber powder modified asphalt.

Description

Technical Field

[0001] The present invention belongs to the technical field of modified asphalt preparation. Background Art

[0002] Approximately 1.5 billion waste tires are generated globally each year, and the total quantity shows a continuous growth trend. Although a variety of treatment technologies have been developed, due to the limitations of the existing process efficiency and cost factors, the overall resource utilization rate of waste tires remains at a relatively low level. It is estimated that currently more than 60% of waste tires are landfilled. Due to their high calorific value characteristics (>30 MJ / kg), low thermal conductivity coefficient (about 0.14 W / m·K), and the characteristics of internal pores being easy to store water, such materials not only significantly increase the fire risk index (flash point >300 °C), but also easily form an environment for the breeding of disease vectors, resulting in serious secondary ecological pollution.

[0003] In the field of solid waste resource utilization, the application of waste tires in road engineering has formed a large-scale technical path. The waste rubber powder prepared by mechanical crushing process can replace 10% - 20% of the matrix asphalt to prepare waste rubber powder modified asphalt. This technical route has dual environmental benefits: on the one hand, it reduces the consumption of non-renewable petroleum resources, and on the other hand, it improves the material recycling rate. Research shows that the incorporation of waste rubber powder can increase the fatigue life of asphalt mixture by 35% - 50%, and improve the rutting resistance performance of the road surface by more than 40%, significantly extending the service life of the road.

[0004] However, the inherent three-dimensional cross-linked network structure of waste rubber powder (mainly composed of C-S and S-S bonds) leads to weak interaction with the asphalt matrix, resulting in obvious phase separation phenomenon during the storage of waste rubber powder modified asphalt, seriously restricting its engineering application. The existing modification technologies are mainly divided into the following aspects: (1) Physical modification method: The cross-linked structure is destroyed by microwave radiation, but there are safety hazards caused by the electromagnetic induction discharge phenomenon caused by the residual tire steel wire; (2) Microbial desulfurization method: The biological enzymatic hydrolysis of sulfur-loving bacteria is used, but there are technical bottlenecks such as long reaction period (>72 h).

[0005] Therefore, exploring a safe and rapid desulfurization method has become the key research direction. Based on this desulfurization technology, the cross-linked structure of waste rubber powder is destroyed, the interaction between waste rubber powder and asphalt is enhanced, the storage stability of waste rubber powder modified asphalt is improved, and the promotion of waste rubber powder modified asphalt is promoted. Summary of the Invention

[0006] The present invention aims to solve the problem that there is a lack of a safe and rapid desulfurization method to destroy the cross-linked structure of waste rubber powder, enhance the interaction between waste rubber powder and asphalt, and improve the storage stability of waste rubber powder modified asphalt, and further provides a method for desulfurizing waste rubber powder modified asphalt with ternary eutectic solvent.

[0007] A method for modifying asphalt with desulfurized waste rubber powder using a ternary deep eutectic solvent, which is carried out according to the following steps:

[0008] I. Preparation of ternary deep eutectic solvent:

[0009] Mix choline chloride, zinc salt and amide compound, and then under constant temperature and stirring conditions, react until the mixture becomes a clear solution to obtain the ternary deep eutectic solvent;

[0010] II. Desulfurization of waste rubber powder with ternary deep eutectic solvent:

[0011] Disperse the waste rubber powder in the ternary deep eutectic solvent, and then carry out the reaction under constant temperature and stirring conditions. After the reaction, rinse and dry to obtain the desulfurized waste rubber powder;

[0012] III. Preparation of modified asphalt:

[0013] Screen the desulfurized waste rubber powder and add it to the base asphalt. Then, under constant temperature and stirring conditions, uniformly disperse the desulfurized waste rubber powder in the base asphalt. Finally, under constant temperature and shearing conditions, reduce the particle size of the desulfurized waste rubber powder to obtain the modified asphalt with desulfurized waste rubber powder using the ternary deep eutectic solvent.

[0014] The beneficial effects of the present invention are:

[0015] (1) The ternary deep eutectic solvent in the present invention is obtained by blending a hydrogen bond donor choline chloride, a hydrogen bond acceptor amide group compound and a Lewis acid zinc salt. The amino group (-NH2) of the amide group compound serves as a hydrogen bond donor to provide a proton (H + ) to the chloride ion (Cl - ) to form an N-H···Cl - hydrogen bond. The zinc salt acts as a Lewis acid, and Zn 2+ can form a coordination bond with the carbonyl oxygen (C=O) or amino group (NH2) in the amide group compound, jointly destroying the original crystal structure of the system, resulting in a further decrease in the melting point, which is beneficial to subsequent full contact with the waste rubber powder and improving the desulfurization modification effect;

[0016] (2) In the present invention, the waste rubber powder is desulfurized and modified based on the ternary deep eutectic solvent. On the one hand, Zn 2+ acts as a Lewis acid to coordinate with the sulfur atom in the sulfur cross-linking bonds (such as S-S, S-C bonds), polarize and weaken the bond energy, and promote the thermal decomposition or oxidative cleavage of the sulfur bonds; on the other hand, at high temperatures, the amide group can accelerate the reaction with the C-S and S-S bonds of the waste rubber powder, resulting in the cleavage of the cross-linking bonds. Through the combined action of the above two aspects, the cross-linking network structure of the waste rubber powder is destroyed to the greatest extent, and the compatibility between the waste rubber powder and the asphalt is improved;

[0017] (3) In the present invention, based on the ternary deep eutectic solvent desulfurized waste rubber powder, the dense three-dimensional network structure of the waste rubber powder is destroyed, its interaction with asphalt is enhanced, and the swelling-degradation process of the waste rubber powder in asphalt is promoted. While ensuring the road performance of the modified asphalt, the stability of the waste rubber powder in asphalt is improved, and the problems that the waste rubber powder is prone to sink during heat storage, causing equipment damage and a decline in the road performance of the waste rubber powder modified asphalt are solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a differential scanning calorimetry spectrum of the ternary deep eutectic solvent prepared in Step 1 of Example 5. DETAILED DESCRIPTION OF THE INVENTION

[0019] DETAILED DESCRIPTION OF THE INVENTION 1: A method for preparing ternary deep eutectic solvent desulfurized waste rubber powder modified asphalt according to this embodiment is carried out according to the following steps:

[0020] I. Preparation of ternary deep eutectic solvent:

[0021] Mix choline chloride, zinc salt and amide compound, and then react under constant temperature and stirring conditions until the mixture becomes a clear solution to obtain a ternary deep eutectic solvent;

[0022] II. Ternary deep eutectic solvent desulfurized waste rubber powder:

[0023] Disperse the waste rubber powder in the ternary deep eutectic solvent, and then react under constant temperature and stirring conditions. After the reaction, rinse and dry to obtain desulfurized waste rubber powder;

[0024] III. Preparation of modified asphalt:

[0025] Sieve the desulfurized waste rubber powder and add it to the matrix asphalt. Then, under constant temperature and stirring conditions, uniformly disperse the desulfurized waste rubber powder in the matrix asphalt. Finally, under constant temperature and shearing conditions, reduce the particle size of the desulfurized waste rubber powder to obtain ternary deep eutectic solvent desulfurized waste rubber powder modified asphalt.

[0026] The melting point of the ternary deep eutectic solvent prepared in Step 1 of this specific embodiment is reduced by 100 °C to 300 °C compared with that of single-component choline chloride.

[0027] The beneficial effects of this embodiment are:

[0028] (1) The ternary deep eutectic solvent in this embodiment is obtained by blending a hydrogen bond donor choline chloride, a hydrogen bond acceptor amide-based compound and a Lewis acid zinc salt. The amino group (-NH2) of the amide-based compound serves as a hydrogen bond donor to provide a proton (H + ) to the chloride ion (Cl - ) to form an N-H···Cl - hydrogen bond. The zinc salt serves as a Lewis acid, in which Zn 2+It can form a coordination bond with the carbonyl oxygen (C=O) or amino group (NH2) in the amide compound, jointly destroying the original crystal structure of the system, resulting in a further decrease in the melting point, which is beneficial to the subsequent full contact with waste rubber powder and improves the desulfurization modification effect;

[0029] (2) In this embodiment, the waste rubber powder is desulfurized and modified based on the ternary eutectic solvent. On the one hand, Zn 2+ As a Lewis acid, it coordinates with the sulfur atoms in the sulfur cross-linking bonds (such as S-S, S-C bonds), polarizes and weakens the bond energy, and promotes the thermal decomposition or oxidative cleavage of the sulfur bonds; on the other hand, under high-temperature conditions, the amide group can accelerate the reaction with the C-S and S-S bonds of the waste rubber powder, resulting in the cleavage of the cross-linking bonds. Through the combined action of the above two aspects, the cross-linking network structure of the waste rubber powder is damaged to the greatest extent, and the compatibility between the waste rubber powder and asphalt is improved;

[0030] (3) In this embodiment, the waste rubber powder is desulfurized based on the ternary eutectic solvent, destroying the dense three-dimensional network structure of the waste rubber powder, enhancing its interaction with asphalt, and promoting the swelling-degradation process of the waste rubber powder in asphalt. While ensuring the road performance of the modified asphalt, the stability of the waste rubber powder in asphalt is improved, solving the problems that the waste rubber powder is prone to sink during heat storage, causing equipment damage and a decline in the road performance of the waste rubber powder modified asphalt.

[0031] Specific Embodiment 2: The difference between this embodiment and Specific Embodiment 1 is that the mass ratio of the zinc salt to choline chloride in Step 1 is 1:(1-40); the mass ratio of choline chloride to the amide compound in Step 1 is 1:(1-20). Others are the same as Specific Embodiment 1.

[0032] Specific Embodiment 3: The difference between this embodiment and one of Specific Embodiments 1 or 2 is that the zinc salt in Step 1 is zinc acetate, zinc chloride, zinc nitrate, zinc acetate or zinc sulfate. Others are the same as Specific Embodiment 1 or 2.

[0033] Specific Embodiment 4: The difference between this embodiment and one of Specific Embodiments 1 to 3 is that the amide compound in Step 1 is carbamamide, urea, acetamide, formamide or caprolactam. Others are the same as Specific Embodiment 3.

[0034] Specific Embodiment 5: The difference between this embodiment and one of Specific Embodiments 1 to 4 is that in Step 1, under the conditions of a constant temperature of 40°C to 100°C and a stirring speed of 20 r / min to 500 r / min, the reaction is carried out for 1 h to 10 h until the mixture becomes a clear solution. Others are the same as Specific Embodiments 1 to 4.

[0035] Specific Embodiment Six: The difference between this embodiment and any one of Specific Embodiments One to Five is as follows: In Step 2, the mass ratio of the waste rubber powder to the ternary deep eutectic solvent is 1:(1 to 100); the particle size of the waste rubber powder in Step 2 is 20 mesh to 200 mesh. Others are the same as those in Specific Embodiments One to Five.

[0036] Specific Embodiment Seven: The difference between this embodiment and any one of Specific Embodiments One to Six is as follows: In Step 2, under the conditions of a constant temperature of 100°C to 200°C and a stirring speed of 1000 r / min to 2200 r / min, the reaction is carried out for 1 h to 6 h. Others are the same as those in Specific Embodiments One to Six.

[0037] Specific Embodiment Eight: The difference between this embodiment and any one of Specific Embodiments One to Seven is as follows: In Step 3, the mass ratio of the desulfurized waste rubber powder to the matrix asphalt in the ternary deep eutectic solvent desulfurized waste rubber powder modified asphalt is 1:(4 to 99). Others are the same as those in Specific Embodiments One to Seven.

[0038] Specific Embodiment Nine: The difference between this embodiment and any one of Specific Embodiments One to Eight is as follows: In Step 3, using ultrasonic vibration, the desulfurized waste rubber powder is passed through a 20-mesh to 80-mesh sieve and then added to the matrix asphalt; in Step 3, under the conditions of a constant temperature of 130°C to 200°C and a stirring speed of 500 r / min to 1000 r / min, stirring is carried out for 1 h to 3 h until the desulfurized waste rubber powder is uniformly dispersed in the matrix asphalt. Others are the same as those in Specific Embodiments One to Eight.

[0039] Specific Embodiment Ten: The difference between this embodiment and any one of Specific Embodiments One to Nine is as follows: In Step 3, under the conditions of a constant temperature of 140°C to 200°C and a shear speed of 2000 r / min to 8000 r / min, shearing is carried out for 1 h to 3 h to reduce the particle size of the desulfurized waste rubber powder. Others are the same as those in Specific Embodiments One to Nine.

[0040] The following examples are used to verify the beneficial effects of the present invention:

[0041] Example One:

[0042] A method for preparing ternary deep eutectic solvent desulfurized waste rubber powder modified asphalt, which is carried out according to the following steps:

[0043] I. Preparation of ternary deep eutectic solvent:

[0044] 10 g of choline chloride, 10 g of zinc salt and 20 g of amide compound are mixed, and then under the conditions of a constant temperature of 40°C and a stirring speed of 100 r / min, the reaction is carried out for 10 h. At this time, the mixture becomes a clear solution, and the ternary deep eutectic solvent is obtained;

[0045] The zinc salt is zinc acetate;

[0046] The amide compound mentioned above is carbamic amide;

[0047] II. Desulfurized waste rubber powder with ternary deep eutectic solvent:

[0048] Disperse 10 g of waste rubber powder in 500 g of ternary deep eutectic solvent, and then react for 2 h under the conditions of a constant temperature of 100 °C and a stirring speed of 1000 r / min. After the reaction, rinse with absolute ethanol and dry to obtain desulfurized waste rubber powder;

[0049] The average particle size of the waste rubber powder mentioned above is 254 μm;

[0050] III. Preparation of modified asphalt:

[0051] Using ultrasonic vibration, under the condition of a frequency of 18 KHz, vibrate the desulfurized waste rubber powder for 10 min to pass through a 60-mesh sieve, then add it to the matrix asphalt, and then stir for 1 h under the conditions of a constant temperature of 140 °C and a stirring speed of 500 r / min to make the desulfurized waste rubber powder evenly dispersed in the matrix asphalt. Finally, shear for 1 h under the conditions of a constant temperature of 140 °C and a shear speed of 2000 r / min to reduce the particle size of the desulfurized waste rubber powder, that is, obtain the modified asphalt with ternary deep eutectic solvent desulfurized waste rubber powder;

[0052] In the modified asphalt with ternary deep eutectic solvent desulfurized waste rubber powder mentioned above, the mass ratio of desulfurized waste rubber powder to matrix asphalt is 10:90;

[0053] The matrix asphalt mentioned above is No. 90 Liaohe Petrochemical asphalt.

[0054] Example 2:

[0055] A method for preparing modified asphalt with ternary deep eutectic solvent desulfurized waste rubber powder, which is carried out according to the following steps:

[0056] I. Preparation of ternary deep eutectic solvent:

[0057] Mix 40 g of choline chloride, 20 g of zinc salt and 200 g of amide compound, and then react for 8 h under the conditions of a constant temperature of 60 °C and a stirring speed of 200 r / min. At this time, the mixture becomes a clear solution to obtain the ternary deep eutectic solvent;

[0058] The zinc salt mentioned above is zinc nitrate;

[0059] The amide compound mentioned above is acetamide;

[0060] II. Desulfurized waste rubber powder with ternary deep eutectic solvent:

[0061] Disperse 15 g of waste rubber powder in 950 g of ternary eutectic solvent, and then react for 3 h under the conditions of a constant temperature of 120 °C and a stirring speed of 1200 r / min. After the reaction, rinse with absolute ethanol and dry to obtain desulfurized waste rubber powder;

[0062] The average particle size of the waste rubber powder is 254 μm;

[0063] III. Preparation of modified asphalt:

[0064] Using ultrasonic vibration, under the condition of a frequency of 18 KHz, vibrate the desulfurized waste rubber powder for 20 min to pass through a 60-mesh sieve, then add it to the matrix asphalt, and then stir for 1.5 h under the conditions of a constant temperature of 145 °C and a stirring speed of 600 r / min to make the desulfurized waste rubber powder evenly dispersed in the matrix asphalt. Finally, shear for 1.5 h under the conditions of a constant temperature of 150 °C and a shear speed of 3000 r / min to reduce the particle size of the desulfurized waste rubber powder, that is, obtain ternary eutectic solvent desulfurized waste rubber powder modified asphalt;

[0065] In the ternary eutectic solvent desulfurized waste rubber powder modified asphalt, the mass ratio of the desulfurized waste rubber powder to the matrix asphalt is 12:88;

[0066] The matrix asphalt is No. 90 Liaohe Petrochemical asphalt.

[0067] Example 3:

[0068] A method for preparing ternary eutectic solvent desulfurized waste rubber powder modified asphalt, which is carried out according to the following steps:

[0069] I. Preparation of ternary eutectic solvent:

[0070] Mix 60 g of choline chloride, 15 g of zinc salt and 300 g of amide compound, and then react for 6 h under the conditions of a constant temperature of 70 °C and a stirring speed of 300 r / min. At this time, the mixture becomes a clear solution to obtain a ternary eutectic solvent;

[0071] The zinc salt is zinc acetate;

[0072] The amide compound is formamide;

[0073] II. Ternary eutectic solvent desulfurized waste rubber powder:

[0074] Disperse 20 g of waste rubber powder in 1000 g of ternary eutectic solvent, and then react for 4 h under the conditions of a constant temperature of 140 °C and a stirring speed of 1400 r / min. After the reaction, rinse with absolute ethanol and dry to obtain desulfurized waste rubber powder;

[0075] The average particle size of the waste rubber powder is 254 μm;

[0076] III. Preparation of modified asphalt:

[0077] Using ultrasonic vibration, under the condition of a frequency of 18 KHz, vibrate the desulfurized waste rubber powder for 30 min to pass through a 60-mesh sieve, then add it to the matrix asphalt, and then under the conditions of a constant temperature of 150 °C and a stirring speed of 700 r / min, stir for 2 h to make the desulfurized waste rubber powder evenly dispersed in the matrix asphalt. Finally, under the conditions of a constant temperature of 160 °C and a shear speed of 4000 r / min, shear for 2 h to reduce the particle size of the desulfurized waste rubber powder, and thus obtain the ternary eutectic solvent desulfurized waste rubber powder modified asphalt;

[0078] In the ternary eutectic solvent desulfurized waste rubber powder modified asphalt, the mass ratio of the desulfurized waste rubber powder to the matrix asphalt is 14:86;

[0079] The matrix asphalt is No. 90 Liaohe Petrochemical asphalt.

[0080] Example 4:

[0081] A method for preparing ternary eutectic solvent desulfurized waste rubber powder modified asphalt, which is carried out according to the following steps:

[0082] I. Preparation of ternary eutectic solvent:

[0083] Mix 100 g of choline chloride, 10 g of zinc salt and 350 g of amide compound, and then under the conditions of a constant temperature of 80 °C and a stirring speed of 400 r / min, react for 4 h. At this time, the mixture becomes a clear solution to obtain the ternary eutectic solvent;

[0084] The zinc salt is zinc sulfate;

[0085] The amide compound is caprolactam;

[0086] II. Ternary eutectic solvent desulfurized waste rubber powder:

[0087] Disperse 25 g of waste rubber powder in 750 g of ternary eutectic solvent, and then under the conditions of a constant temperature of 160 °C and a stirring speed of 1600 r / min, react for 5 h. After the reaction, rinse with anhydrous ethanol and dry to obtain the desulfurized waste rubber powder;

[0088] The average particle size of the waste rubber powder is 254 μm;

[0089] III. Preparation of modified asphalt:

[0090] Using ultrasonic vibration, under the condition of a frequency of 18 KHz, vibrate the desulfurized waste rubber powder for 40 min to pass through a 60-mesh sieve, then add it to the matrix asphalt, and then under the conditions of a constant temperature of 160 °C and a stirring speed of 800 r / min, stir for 2.5 h to make the desulfurized waste rubber powder evenly dispersed in the matrix asphalt. Finally, under the conditions of a constant temperature of 170 °C and a shear speed of 5000 r / min, shear for 2.5 h to reduce the particle size of the desulfurized waste rubber powder, that is, obtain the ternary deep eutectic solvent desulfurized waste rubber powder modified asphalt;

[0091] In the ternary deep eutectic solvent desulfurized waste rubber powder modified asphalt, the mass ratio of the desulfurized waste rubber powder to the matrix asphalt is 16:84;

[0092] The matrix asphalt is 90# Liaohe Petrochemical asphalt.

[0093] Example Five:

[0094] A method for preparing ternary deep eutectic solvent desulfurized waste rubber powder modified asphalt, which is carried out according to the following steps:

[0095] I. Preparation of ternary deep eutectic solvent:

[0096] Mix 150 g of choline chloride, 12 g of zinc salt and 450 g of amide compound, and then under the conditions of a constant temperature of 90 °C and a stirring speed of 500 r / min, react for 2 h. At this time, the mixture becomes a clear solution to obtain the ternary deep eutectic solvent;

[0097] The zinc salt is zinc chloride;

[0098] The amide compound is urea;

[0099] II. Ternary deep eutectic solvent desulfurized waste rubber powder:

[0100] Disperse 30 g of waste rubber powder in 480 g of ternary deep eutectic solvent, and then under the conditions of a constant temperature of 180 °C and a stirring speed of 1800 r / min, react for 6 h. After the reaction, rinse with anhydrous ethanol and dry to obtain the desulfurized waste rubber powder;

[0101] The average particle size of the waste rubber powder is 254 μm;

[0102] III. Preparation of modified asphalt:

[0103] Using ultrasonic vibration, under the condition of a frequency of 18 KHz, the desulfurized waste rubber powder was vibrated for 50 min to pass through a 60-mesh sieve, and then added to the matrix asphalt. Then, under the conditions of a constant temperature of 180 °C and a stirring speed of 900 r / min, it was stirred for 3 h to make the desulfurized waste rubber powder uniformly dispersed in the matrix asphalt. Finally, under the conditions of a constant temperature of 190 °C and a shear speed of 6000 r / min, it was sheared for 3 h to reduce the particle size of the desulfurized waste rubber powder, thus obtaining the ternary eutectic solvent desulfurized waste rubber powder modified asphalt;

[0104] In the ternary eutectic solvent desulfurized waste rubber powder modified asphalt, the mass ratio of the desulfurized waste rubber powder to the matrix asphalt is 18:82;

[0105] The matrix asphalt is No. 90 Liaohe Petrochemical asphalt.

[0106] Comparative Example 1, in this comparative example, non-desulfurized waste rubber powder was added: The difference between this comparative example and Example 4 is that: Step 1 and Step 2 were cancelled, and in Step 3, the desulfurized waste rubber powder was replaced with waste rubber powder. Others are the same as Example 4.

[0107] Comparative Example 2, in this comparative example, commercially available desulfurized waste rubber powder was added: The difference between this comparative example and Example 4 is that: Step 1 and Step 2 were cancelled, and in Step 3, the desulfurized waste rubber powder was replaced with commercially available desulfurized waste rubber powder (model TL-800). Others are the same as Example 4.

[0108] The desulfurized waste rubber powder prepared in Step 2 of Examples 1 to 5, the waste rubber powder in Comparative Example 1, and the commercially available desulfurized waste rubber powder in Comparative Example 2 were immersed in toluene solution (25 °C). Based on the principle of equilibrium swelling, their crosslinking density was calculated, and the test results are shown in Table 1:

[0109] Table 1 Crosslinking density of waste rubber powder and desulfurized waste rubber powder

[0110] <![CDATA[Crosslink density (×10 -4 mol / cm -3 )]]> Comparative Example 1 2.52 Comparative Example 2 1.63 Example 1 1.55 Example 2 1.42 Example 3 1.36 Example 4 1.15 Example 5 1.10

[0111] As can be seen from Table 1, the crosslinking density based on the ternary eutectic solvent desulfurized waste rubber powder is significantly lower than that of the non-desulfurized waste rubber powder and the commercially available desulfurized waste rubber powder. This is because Zn 2+ As a Lewis acid, coordinates with the sulfur atoms in the sulfur crosslinking bonds (such as S-S, S-C bonds), polarizes and weakens the bond energy, and promotes the thermal decomposition or oxidative cleavage of the sulfur bonds; at the same time, under high-temperature conditions, the amide group can accelerate the reaction with the C-S and S-S bonds of the waste rubber powder, resulting in the cleavage of the crosslinking bonds. Through the combined action of the above two aspects, the crosslinking network structure of the waste rubber powder is damaged to the greatest extent, resulting in a decrease in the crosslinking density, which is beneficial to its interaction with asphalt.

[0112] The ternary deep eutectic solvent desulfurized waste rubber powder modified asphalt prepared in Examples 1 to 5 and the modified asphalt prepared in Comparative Examples 1 and 2 were respectively placed in a segregation tube, and then kept at a constant temperature of 163°C for 48 h. The softening point difference between the upper and lower ends was measured, that is, the segregation softening point difference; the creep rate and the ductility at 5°C of the modified asphalt were measured. The test results are shown in Table 2:

[0113] Table 2 Test results of modified asphalt

[0114]

[0115] As can be seen from Table 2, the waste rubber powder modified asphalt based on ternary deep eutectic solvent desulfurization has certain improvements in performance compared with the commercially available desulfurized waste rubber powder modified asphalt. The waste rubber powder modified asphalt based on ternary deep eutectic solvent desulfurization has significant improvements in the ductility at 5°C, creep rate and stability in asphalt (segregation softening point difference) compared with the waste rubber powder modified asphalt. This is because the three-dimensional network structure of the waste rubber powder is damaged, accelerating the swelling-degradation process of the waste rubber powder in asphalt, resulting in an increased degree of degradation of the waste rubber powder in asphalt. Therefore, the low-temperature crack resistance of the desulfurized waste rubber powder modified asphalt is significantly improved, and the segregation softening point is significantly reduced, which is more conducive to the popularization and application of the waste rubber powder modified asphalt.

[0116] Figure 1 It is the differential scanning calorimetry spectrum of the ternary deep eutectic solvent prepared in Step 1 of Example 5. As can be seen from the figure, the upward peak of the DSC curve is an endothermic peak, representing the phase change of the sample from solid to liquid. Therefore, the melting point of the ternary deep eutectic solvent obtained is 16°C, which is lower than that of choline chloride (305°C) by 289°C.

Claims

1. A method for modifying asphalt by desulfurizing waste rubber powder using a ternary low eutectic solvent, characterized in that It is carried out in the following steps:

1. Preparation of ternary deep eutectic solvent: The choline chloride, the zinc salt and the amide compound are mixed, and then reacted at a constant temperature and under stirring conditions until the mixture becomes a clear solution to obtain a ternary deep eutectic solvent; 2. Ternary eutectic solvent desulfurization of waste rubber powder: The waste rubber powder is dispersed in a ternary low eutectic solvent, and then reacted under constant temperature and stirring conditions, and after the reaction is completed, it is rinsed and dried to obtain desulfurized waste rubber powder; 3. Preparation of modified asphalt: The desulfurized waste rubber powder is sieved and added to the base asphalt, then the desulfurized waste rubber powder is evenly dispersed in the base asphalt under constant temperature and stirring conditions, and finally the particle size of the desulfurized waste rubber powder is reduced under constant temperature and shear conditions to obtain the ternary low eutectic solvent desulfurized waste rubber powder modified asphalt.

2. The method for modifying asphalt by desulfurizing waste rubber powder with a ternary deep eutectic solvent according to claim 1, characterized in that The mass ratio of the zinc salt to the choline chloride in step 1 is 1:(1-40); the mass ratio of the choline chloride to the amide compound in step 1 is 1:(1-20).

3. The method for modifying asphalt by desulfurizing waste rubber powder with a ternary deep eutectic solvent according to claim 1, characterized in that The zinc salt described in step 1 is zinc acetate, zinc chloride, zinc nitrate, zinc acetate or zinc sulfate.

4. The method for modifying asphalt by desulfurizing waste rubber powder with a ternary deep eutectic solvent according to claim 1, characterized in that The amide compound described in step 1 is aminoformamide, urea, acetamide, formamide or caprolactam.

5. The method for modifying asphalt by desulfurizing waste rubber powder with a ternary deep eutectic solvent according to claim 1, characterized in that In step 1, the reaction is carried out for 1 h to 10 h at a constant temperature of 40° C. to 100° C. and a stirring speed of 20 r / min to 500 r / min until the mixture becomes a clear solution.

6. The method for modifying asphalt by desulfurizing waste rubber powder with a ternary deep eutectic solvent according to claim 1, characterized in that The mass ratio of the waste rubber powder described in step 2 to the ternary low eutectic solvent is 1:(1-100); the particle size of the waste rubber powder described in step 2 is 20 mesh to 200 mesh.

7. The method for modifying asphalt by desulfurizing waste rubber powder with a ternary deep eutectic solvent according to claim 1, characterized in that In step 2, the reaction is carried out for 1 h to 6 h at a constant temperature of 100° C. to 200° C. and a stirring speed of 1000 r / min to 2200 r / min.

8. The method for modifying asphalt by desulfurizing waste rubber powder with a ternary deep eutectic solvent according to claim 1, characterized in that The mass ratio of desulfurized waste rubber powder to base asphalt in the ternary low eutectic solvent desulfurized waste rubber powder modified asphalt described in step three is 1: (4-99).

9. The method for modifying asphalt by desulfurizing waste rubber powder with a ternary deep eutectic solvent according to claim 1, characterized in that In step three, ultrasonic vibration is used to pass the desulfurized waste rubber powder through a 20-mesh to 80-mesh sieve and then add it to the base asphalt; in step three, stirring is performed for 1h to 3h at a constant temperature of 130°C to 200°C and a stirring speed of 500r / min to 1000r / min until the desulfurized waste rubber powder is evenly dispersed in the base asphalt.

10. The method for modifying asphalt by desulfurizing waste rubber powder with a ternary deep eutectic solvent according to claim 1, characterized in that In step 3, shearing is performed for 1 h to 3 h at a constant temperature of 140° C. to 200° C. and a shearing speed of 2000 r / min to 8000 r / min to reduce the particle size of the desulfurized waste rubber powder.

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