High-performance cold patch asphalt mixture as well as preparation method and application thereof

Abstract

The invention discloses a high-performance cold patch asphalt mixture as well as a preparation method and application thereof, belongs to the technical field of asphalt mixture processing, and is used for solving the technical problem that the curing property, the aging resistance and the mechanical property of an asphalt mixture in the prior art need to be further improved. The modified nano-crystalline cellulose aerogel modified asphalt comprises the following components in parts by weight: 90-100 parts of a component A, 60-70 parts of a component B and 50-60 parts of a component C. The modified nano-crystalline cellulose aerogel modified asphalt is prepared by taking matrix asphalt, modified nano-crystalline cellulose aerogel and a diluent as the component A, taking a modified curing agent and alkaline aggregate which can be rapidly cured at room temperature as the component B and taking modified epoxy resin, a photoinitiator and a surfactant as the component C, the curing performance and the aging resistance of the cold patch asphalt mixture are effectively improved, and the mechanical performance of the cold patch asphalt mixture is also improved.

Description

Technical Field

[0001] The present invention relates to the technical field of asphalt mixture processing, and particularly relates to a high-performance cold patch asphalt mixture, a preparation method thereof, and an application thereof. Background Art

[0002] In recent years, traditional hot mix asphalt mixtures have problems such as high energy consumption, large carbon emissions, and volatile organic compound pollution due to the need for high-temperature mixing and construction. With the tightening of environmental protection regulations, cold mix asphalt mixtures have attracted much attention due to their characteristics of construction at normal temperature. However, conventional cold mix asphalt relies on emulsified asphalt or solvent-based binders, and has defects such as low early strength, long forming cycle, and poor resistance to water damage, making it difficult to meet the performance requirements of heavy-duty traffic or extreme climate road surfaces. In recent years, research has been carried out to improve the performance of cold mix asphalt by introducing modifiers such as SBS, epoxy resin-based polymers, and nanomaterials. However, although epoxy resin modification can improve strength, it significantly prolongs the curing time and has insufficient adaptability to low-temperature environments.

[0003] When preparing asphalt mixtures, adding epoxy resin is a commonly used method to enhance the performance of asphalt mixtures. However, epoxy resin is a thermosetting polymer, and its molecules contain epoxy groups. During the curing process, the epoxy groups need to react with chemical groups such as amino or carboxyl groups in the curing agent to form a three-dimensional cross-linked structure. This cross-linking reaction requires a relatively high temperature. If the temperature is low, the reaction rate is slow, resulting in incomplete curing, which affects the mechanical strength, temperature resistance, and durability of the asphalt mixture. Moreover, during the curing process of epoxy resin, a three-dimensional network structure is formed through cross-linking reaction. Although this structure improves the mechanical properties, it also makes the resin relatively rigid and lacks sufficient flexibility. Under long-term environmental stress and temperature changes, the molecular chains of epoxy resin may break, and the cross-linked structure becomes loose, resulting in a decrease in the anti-aging performance of the asphalt mixture. In addition, the added nanomaterials are difficult to form good interfacial compatibility with the asphalt mixture due to insufficient hydrophilicity and dispersibility.

[0004] In view of the technical defects in this regard, a solution is proposed herein. Summary of the Invention

[0005] The purpose of the present invention is to provide a high-performance cold patch asphalt mixture, a preparation method thereof, and an application thereof, so as to solve the technical problems that the curing performance, anti-aging performance, and mechanical performance of asphalt mixtures in the prior art need to be further improved.

[0006] The purpose of the present invention can be achieved through the following technical solutions: A high-performance cold patch asphalt mixture, comprising the following components by weight: 90-100 parts of component A, 60-70 parts of component B, and 50-60 parts of component C;

[0007] The component A is composed of matrix asphalt, modified nanocellulose aerogel and diluent in a dosage ratio of 200 - 250 g : 50 - 70 g : 60 - 80 g;

[0008] The component B is composed of modified curing agent and alkaline aggregate in a dosage ratio of 600 - 800 g : 400 - 500 g;

[0009] The component C is composed of modified epoxy resin, photoinitiator and surfactant in a dosage ratio of 100 - 150 g : 5 - 10 g : 20 - 25 g.

[0010] Furthermore, the matrix asphalt is 70# asphalt, the diluent is composed of diesel and oleic acid in a mass ratio of 1:1, the alkaline aggregate is composed of gravel with a size of 2.5 - 5.0 mm, gravel with a size of 1 - 2 mm and quicklime powder in a mass ratio of 1:1:2, the photoinitiator is 2 - hydroxy - 2 - methyl - 1 - phenyl - 1 - propanone, and the surfactant is polyethylene glycol monooleate.

[0011] Furthermore, the modified nanocellulose aerogel is prepared by the following steps:

[0012] A1. Place nanocellulose, N,N - dimethylformamide, 4 - dimethylaminopyridine and triethylamine in a reaction kettle, keep it in an ice bath at 0 - 5 °C, stir for 30 - 60 min, add succinic anhydride, heat up to 40 - 50 °C, and perform post - treatment to obtain carboxylated nanocellulose;

[0013] Reaction principle for the preparation of carboxylated nanocellulose:

[0014] During the reaction process, the low - temperature state activates the hydroxyl groups on the surface of nanocellulose. Under the action of the nucleophilic catalyst 4 - dimethylaminopyridine and the base catalyst triethylamine, a nucleophilic reaction occurs between succinic anhydride and the hydroxyl groups, the ring of succinic anhydride opens, and carboxylated nanocellulose is obtained.

[0015] A2. Place carboxylated nanocellulose and deionized water in a three - necked flask, ultrasonically disperse for 30 - 60 min to obtain a nanocellulose mixture;

[0016] A3. Inject the nanocellulose mixture into a silica gel mold, freeze for 1 - 2 h, and perform freeze - drying to obtain the modified nanocellulose aerogel.

[0017] The reaction principle for the preparation of the modified nanocellulose aerogel is:

[0018] After injecting the nanofibrillated cellulose mixture into a silicone mold, it is placed in a low-temperature environment and frozen for 1-2 hours. During the freezing process, water molecules gradually form ice crystals, and the growth of the ice crystals pushes the nanofibrillated cellulose into the gaps between the ice crystals, forming a preliminary porous structure. The frozen sample is transferred to a freeze dryer and sublimated under vacuum conditions. The ice crystals sublime from the solid state to the gaseous state, avoiding the damage to the pore structure caused by the surface tension of liquid water.

[0019] Further, in step A1, the dosage ratio of the nanofibrillated cellulose, N,N-dimethylformamide, 4-dimethylaminopyridine, triethylamine, and succinic anhydride is 100-150 g: 1000-1500 mL: 30-40 g: 40-50 g: 60-70 g. The post-treatment steps include: after the reaction is completed, when the reaction cools down to room temperature, filtration is carried out. The filter cake is washed with anhydrous ethanol 1-2 times, transferred to a drying oven at a temperature of 40-50 °C, and dried to constant weight to obtain carboxylated nanofibers; in step A2, the dosage ratio of the carboxylated nanofibrillated cellulose and deionized water is 100-200 g: 2000-4000 mL; in step A3, the freeze-drying operation includes: placing the frozen nanofibrillated cellulose solid in a freeze dryer at a temperature of -60--80 °C and a pressure of 10-15 Pa, and freeze-drying for 24-48 h to obtain the modified nanofibrillated cellulose aerogel.

[0020] Further, the preparation method of the modified curing agent is: putting thiourea, 1,4-butanediamine, and 2,4,6-tris(dimethylaminomethyl)phenol into a reaction kettle, heating to 90-140 °C, holding the temperature for reaction for 40-60 min, and performing post-treatment to obtain the modified curing agent.

[0021] The preparation reaction formula of the modified curing agent is:

[0022]

[0023] The preparation reaction principle of the modified curing agent is:

[0024] During the reaction process, thiourea and 1,4-butanediamine undergo a polycondensation reaction at high temperature. The products generated include two kinds. One is the polycondensation product Ⅰ formed by the condensation reaction of thiourea and the amino group of 1,4-butanediamine. One is ammonium thiocyanate produced by the decomposition of thiourea in a high-temperature environment as product Ⅱ. The other is the nucleophilic reaction product of ammonium thiocyanate and 2,4,6-tris(dimethylaminomethyl)phenol. The dimethylamino group in 2,4,6-tris(dimethylaminomethyl)phenol attacks the sulfur atom in the thiocyanate root as a nucleophilic reagent to form an S-N bond, obtaining the polycondensation product Ⅲ. Product Ⅰ, product Ⅱ, and product Ⅲ together constitute the modified curing agent.

[0025] Furthermore, the dosage ratio of thiourea, 1,4-butanediamine, and 2,4,6-tris(dimethylaminomethyl)phenol is 300-600 g: 600-800 g: 1000-1200 g. The post-treatment step includes: after the reaction is completed, wait for the reaction to cool to room temperature, perform suction filtration, wash the filter cake with ethanol 1-2 times, transfer it to a drying oven at 50-60 °C, and dry it to a constant weight to obtain the modified curing agent.

[0026] Furthermore, the modified epoxy resin is prepared by the following steps:

[0027] B1. Place hydroxyl-terminated polybutadiene, ethyl acetate, and dibutyltin dilaurate in a reaction kettle protected by a nitrogen atmosphere, heat up to 45-65 °C, add isophorone diisocyanate, and keep the temperature for reaction for 2-3 h, and perform post-treatment to obtain the precursor of the modified epoxy resin.

[0028] The preparation reaction formula of the precursor of the modified epoxy resin is:

[0029]

[0030] The preparation reaction principle of the precursor of the modified epoxy resin is:

[0031] During the reaction process, under the catalysis of dibutyltin dilaurate, the hydroxyl group of hydroxyl-terminated polybutadiene and the primary carbon isocyanate group of isophorone diisocyanate undergo a nucleophilic addition reaction to obtain the precursor of the modified epoxy resin capped with isophorone diisocyanate.

[0032] B2. Place the precursor of the modified epoxy resin, toluene, and bisphenol A epoxy resin in a reaction kettle, heat up to 80-90 °C, keep the temperature for reaction for 2-3 h, and perform post-treatment to obtain the modified epoxy resin.

[0033] The preparation reaction formula of the modified epoxy resin is:

[0034]

[0035]

[0036] The preparation reaction principle of the modified epoxy resin is:

[0037] During the reaction process, the isocyanate group of the precursor of the modified epoxy resin and the hydroxyl group of bisphenol A epoxy resin undergo a nucleophilic addition reaction to obtain the modified epoxy resin.

[0038] Further, in step B1, the dosage of isophorone diisocyanate is 2 times the total molar amount of hydroxyl groups of hydroxyl-terminated polybutadiene. The dosage ratio of hydroxyl-terminated polybutadiene, ethyl acetate, and dibutyltin dilaurate is 100 - 200 g : 500 - 800 mL : 5 - 10 g. The post-treatment step includes: after the reaction is completed, transferring the reaction solution to a rotary evaporator at a temperature of 40 - 50 °C and rotating until no liquid is collected to obtain a modified epoxy resin precursor; in step B2, the dosage ratio of the modified epoxy resin precursor, dibutyltin dilaurate, toluene, and bisphenol A epoxy resin is 200 - 300 g : 10 - 15 g : 1500 - 2000 mL : 400 - 500 g. The post-treatment step includes: after the reaction is completed, adding ethanol to the reaction solution, heating to 100 - 110 °C, and performing vacuum distillation until no liquid is collected to obtain a modified epoxy resin.

[0039] Further, a preparation method of a high-performance cold patch asphalt mixture includes the following steps:

[0040] S1. Place matrix asphalt, modified nanocellulose aerogel, and a diluent in a reaction kettle, heat to 100 - 120 °C, and stir for 30 - 60 min to obtain component A for standby;

[0041] S2. Place a modified curing agent and alkaline aggregate in a reaction kettle, heat to 40 - 50 °C, and stir for 5 - 10 minutes to obtain component B for standby;

[0042] S3. Mix modified epoxy resin, a photoinitiator, and a surfactant evenly to obtain component C for standby;

[0043] S4. Place component A and component B in a reaction kettle, stir for 3 - 6 min, add component C, and stir at a speed of 3000 - 4000 r / min for 5 - 8 min to obtain a cold patch asphalt mixture.

[0044] Further, an application of a high-performance cold patch asphalt mixture is to apply a high-performance cold patch asphalt mixture to road repair.

[0045] The present invention has the following beneficial effects:

[0046] 1. The present invention prepares a cold patch asphalt mixture by using matrix asphalt, modified nanocellulose aerogel and diluent as component A, a modified curing agent and alkaline aggregate that can be rapidly cured at room temperature as component B, and modified epoxy resin, photoinitiator and surfactant as component C. In the present invention, nanocellulose is carboxylated and the carboxylated nanocellulose is prepared into a three-dimensional porous modified nanocellulose aerogel. A large number of carboxyl groups on the surface of the carboxylated nanocellulose aerogel can form chemical crosslinks with the epoxy groups on the surface of the modified epoxy resin, improving the dispersibility of nanocellulose in the modified epoxy resin and enhancing the mechanical properties of the epoxy resin. At the same time, the hydroxyl groups on the surface of the modified nanocellulose aerogel can form hydrogen bonds with the hydroxyl groups on the molecular chain of the modified epoxy resin, improving the adhesion of the phase interface. When subjected to external force, the porous structure of the modified nanocellulose aerogel provides physical anchor points, restricting the movement of asphalt molecular chains and improving the mechanical strength and toughness of the material.

[0047] 2. The present invention prepares a modified curing agent by reacting thiourea, 1,4-butanediamine and 2,4,6-tris(dimethylaminomethyl)phenol. The main components of the modified curing agent are three kinds: the polycondensation product Ⅰ of thiourea and 1,4-butanediamine, and the thiocyanate amine produced by the decomposition of thiourea in a high-temperature environment is product Ⅱ. Thiourea has a large number of active hydrogens in its molecule, which can not only improve the reaction activity and accelerate the reaction rate, but also reduce the curing temperature of the curing agent. And by modifying polyamine with thiourea groups to introduce mercapto groups, the curing rate of amine curing agents is significantly improved. On the other hand, part of the thiocyanate amine produced by the decomposition of thiourea reacts with 2,4,6-tris(dimethylaminomethyl)phenol to form product Ⅲ. This product not only has the possibility of curing epoxy with cyanamide, but also has a very fast promoting effect on the curing reaction of the modified polyamine containing mercapto groups due to the presence of a tertiary amine structure in itself, improving the curing time of the asphalt mixture and reducing the curing temperature.

[0048] 3. The present invention modifies the terminal hydroxyl polybutadiene by isophorone diisocyanate capping to obtain a modified epoxy resin precursor, and then crosslinks bisphenol A epoxy resin with the modified epoxy resin precursor through a nucleophilic addition reaction to obtain a modified epoxy resin. The flexible long-chain structure of the terminal hydroxyl polybutadiene undergoes a ring-opening reaction with the epoxy group of the epoxy resin through the hydroxyl group at its end to form a crosslinked network. This crosslinked structure not only enhances the mechanical strength of the asphalt mixture, but also improves its toughness and fatigue resistance. At the same time, the rigid benzene ring structure of bisphenol A epoxy resin provides good thermal stability and anti-deformation ability. At the same time, the unsaturated double bonds in the terminal hydroxyl polybutadiene can undergo a free radical polymerization reaction through a photoinitiator to form a chemical crosslink with the diluent oleic acid in the asphalt mixture, further enhancing the interfacial compatibility between the components of the asphalt mixture. This molecular-level synergistic effect makes the asphalt mixture have higher crack resistance, durability and anti-aging performance. The quicklime in the alkaline aggregate releases heat when encountering water during the preparation of the asphalt mixture, providing a heat source for the curing of the asphalt mixture and promoting the curing degree and curing time of the asphalt mixture. Detailed implementation mode

[0049] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work belong to the scope of protection of the present invention.

[0050] The 70# asphalt used in the present invention is purchased from Shouguang Fangyou Waterproof Materials Co., Ltd., with a packaging specification of 50 Kg and a grade of first-class product;

[0051] The bisphenol A epoxy resin used in the present invention is purchased from Shandong Qiansheng Chemical Co., Ltd., with a brand number of E51;

[0052] The terminal hydroxyl polybutadiene used in the present invention is purchased from Wuhan Lanabai Pharmaceutical and Chemical Co., Ltd., and the product grade is analytical pure.

[0053] Example 1

[0054] This example provides a preparation method for a high-performance cold-patch asphalt mixture, including the following steps:

[0055] S1. Prepare component A

[0056] Mix diesel and oleic acid evenly according to a mass ratio of 1:1 to obtain a diluent;

[0057] Weigh: 100 g of nanocellulose, 1000 mL of N,N-dimethylformamide, 30 g of 4-dimethylaminopyridine and 40 g of triethylamine and place them in a reaction kettle. Cool to 0 °C in an ice bath, stir for 30 min, add 60 g of succinic anhydride, heat up to 40 °C. After the reaction is completed, wait for the reaction to cool to room temperature, filter by suction. Wash the filter cake once with absolute ethanol, transfer it to a drying oven at 40 °C, and dry to constant weight to obtain carboxylated nanocellulose;

[0058] Weigh: 100 g of carboxylated nanocellulose and 200 mL of deionized water and place them in a three-necked flask. Ultrasonically disperse for 30 min to obtain a nanocellulose mixture;

[0059] Inject the nanocellulose mixture into a silica gel mold, freeze for 1 h. Place the frozen nanocellulose solid in a freeze dryer at -60 °C and 10 Pa, and freeze-dry for 24 h to obtain a modified nanocellulose aerogel;

[0060] Weigh: Place 200 g of 70# asphalt, 50 g of modified nanocellulose aerogel and 60 g of diluent in a reaction kettle, heat up to 100 °C, stir for 30 min to obtain Component A for standby.

[0061] S2. Prepare Component B

[0062] Weigh: Place 300 g of thiourea, 600 g of 1,4-butanediamine and 1000 g of 2,4,6-tris(dimethylaminomethyl)phenol in a reaction kettle, heat up to 90 °C, keep the temperature for reaction for 40 min, and perform post-treatment to obtain a modified curing agent;

[0063] Mix 2.5-mm gravel, 1-mm gravel and quicklime powder evenly according to a mass ratio of 1:1:2 to obtain alkaline aggregate for standby;

[0064] Weigh: Place 600 g of modified curing agent and 400 g of alkaline aggregate in a reaction kettle, heat up to 40 °C, stir for 5 minutes to obtain Component B for standby.

[0065] S3. Prepare Component C

[0066] Weigh: Place 100 g of hydroxyl-terminated polybutadiene, 500 mL of ethyl acetate and 5 g of dibutyltin dilaurate in a reaction kettle protected by a nitrogen atmosphere, heat up to 45 °C, add isophorone diisocyanate according to 2 times the total molar amount of hydroxyl groups of hydroxyl-terminated polybutadiene, keep the temperature for reaction for 2 h. After the reaction is completed, transfer the reaction solution to a rotary evaporator at 40 °C and rotate until no liquid is collected to obtain a modified epoxy resin precursor;

[0067] Weigh: 200 g of modified epoxy resin precursor, 10 g of dibutyltin dilaurate, 1500 mL of toluene and 400 g of bisphenol A epoxy resin and place them in a reaction kettle. Heat up to 80 °C and keep the temperature for reaction for 2 h. After the reaction is completed, add ethanol to the reaction solution, heat up to 100 °C, and carry out vacuum distillation until no liquid is drawn out to obtain the modified epoxy resin;

[0068] Weigh: 100 g of modified epoxy resin, 5 g of 2-hydroxy-2-methyl-1-phenyl-1-propanone and 20 g of polyethylene glycol monooleate and place them in a reaction kettle, mix evenly to obtain Component C for standby.

[0069] S4. Prepare asphalt mixture

[0070] Weigh by weight: 90 parts of Component A and 60 parts of Component B and place them in a reaction kettle, stir for 3 min, add 50 parts of Component C, and stir at a speed of 3000 r / min for 5 min to obtain the cold patch asphalt mixture.

[0071] Example 2

[0072] This example provides a preparation method of a high-performance cold patch asphalt mixture, including the following steps:

[0073] S1. Prepare Component A

[0074] Mix diesel and oleic acid evenly according to the mass ratio of 1:1 to obtain a diluent;

[0075] Weigh: 125 g of nanocellulose, 1250 mL of N,N-dimethylformamide, 35 g of 4-dimethylaminopyridine and 45 g of triethylamine and place them in a reaction kettle, cool to 3 °C in an ice bath, stir for 45 min, add 65 g of succinic anhydride, heat up to 45 °C, after the reaction is completed, wait for the reaction to cool to room temperature, carry out suction filtration, wash the filter cake with anhydrous ethanol twice, transfer it to a drying oven at 45 °C, and dry to constant weight to obtain carboxylated nanocellulose;

[0076] Weigh: 150 g of carboxylated nanocellulose and 3000 mL of deionized water and place them in a three-necked flask, carry out ultrasonic dispersion for 45 min to obtain a nanocellulose mixture;

[0077] Inject the nanocellulose mixture into a silica gel mold, freeze for 2 h, place the frozen nanocellulose solid in a freeze dryer at -70 °C and 12 Pa, and carry out freeze drying for 36 h to obtain a modified nanocellulose aerogel;

[0078] Weigh: Place 225 g of 70# asphalt, 60 g of modified nanocellulose aerogel and 60 - 80 g of diluent in a reaction kettle, heat up to 110 °C, and stir for 45 min to obtain Component A for standby.

[0079] S2. Prepare Component B

[0080] Weigh: 450 g of thiourea, 700 g of 1,4 - butanediamine and 1100 g of 2,4,6 - tris(dimethylaminomethyl)phenol, place them in a reaction kettle, heat up to 110 °C, keep the temperature for reaction for 50 min, and carry out post - treatment to obtain a modified curing agent;

[0081] Mix gravel with a size of 4 mm, gravel with a size of 1.5 mm and quicklime powder evenly according to the mass ratio of 1:1:2 to obtain alkaline aggregate for standby;

[0082] Weigh: 700 g of modified curing agent and 450 g of alkaline aggregate, place them in a reaction kettle, heat up to 45 °C, stir for 7 minutes to obtain Component B for standby.

[0083] S3. Prepare Component C

[0084] Weigh: 150 g of hydroxyl - terminated polybutadiene, 700 mL of ethyl acetate and 7 g of dibutyltin dilaurate, place them in a reaction kettle protected by a nitrogen atmosphere, heat up to 55 °C, add isophorone diisocyanate according to 2 times the total molar amount of hydroxyl groups of hydroxyl - terminated polybutadiene, keep the temperature for reaction for 2.5 h. After the reaction is completed, transfer the reaction solution to a rotary evaporator at 45 °C and rotate until no liquid is collected to obtain a modified epoxy resin precursor;

[0085] Weigh: 250 g of modified epoxy resin precursor, 12 g of dibutyltin dilaurate, 1700 mL of toluene and 450 g of bisphenol A epoxy resin, place them in a reaction kettle, heat up to 85 °C, keep the temperature for reaction for 2.5 h. After the reaction is completed, add ethanol to the reaction solution, heat up to 105 °C, and carry out vacuum distillation until no liquid is collected to obtain a modified epoxy resin;

[0086] Weigh: 125 g of modified epoxy resin, 7 g of 2 - hydroxy - 2 - methyl - 1 - phenyl - 1 - propanone and 22 of polyethylene glycol monooleate, place them in a reaction kettle and mix evenly to obtain Component C for standby.

[0087] S4. Prepare asphalt mixture

[0088] Weigh by weight: 95 parts of Component A and 65 parts of Component B, place them in a reaction kettle, stir for 4 min, add 55 parts of Component C, and stir at a speed of 3500 r / min for 6 min to obtain a cold - patch asphalt mixture.

[0089] Example 3

[0090] This example provides a preparation method of a high - performance cold - patch asphalt mixture, including the following steps:

[0091] S1. Prepare Component A

[0092] Mix diesel and oleic acid evenly according to the mass ratio of 1:1 to obtain a diluent;

[0093] Weigh: 150 g of nanocellulose, 1500 mL of N,N-dimethylformamide, 40 g of 4-dimethylaminopyridine and 50 g of triethylamine and place them in a reaction kettle. Cool to -5 °C in an ice bath, stir for 60 min, add 60 - 70 g of succinic anhydride, heat to 50 °C. After the reaction is completed, wait for the reaction to cool to room temperature, filter by suction, wash the filter cake twice with absolute ethanol, transfer it to a drying oven at 50 °C, and dry to constant weight to obtain carboxylated nanocellulose;

[0094] Weigh: 200 g of carboxylated nanocellulose and 4000 mL of deionized water and place them in a three-necked flask. Ultrasonically disperse for 60 min to obtain a nanocellulose mixture;

[0095] Inject the nanocellulose mixture into a silica gel mold and freeze for 2 h. Place the frozen nanocellulose solid in a freeze dryer at -80 °C and 15 Pa and freeze-dry for 48 h to obtain a modified nanocellulose aerogel;

[0096] Weigh: Place 250 g of 70# asphalt, 70 g of modified nanocellulose aerogel and 80 g of diluent in a reaction kettle, heat to 120 °C, stir for 60 min to obtain Component A for standby.

[0097] S2. Prepare Component B

[0098] Weigh: 600 g of thiourea, 800 g of 1,4-butanediamine and 1200 g of 2,4,6-tris(dimethylaminomethyl)phenol and place them in a reaction kettle. Heat to 140 °C, hold the reaction for 60 min, and perform post-treatment to obtain a modified curing agent;

[0099] Mix 5.0 mm gravel, 2 mm gravel and quicklime powder evenly according to the mass ratio of 1:1:2 to obtain alkaline aggregate for standby;

[0100] Weigh: 800 g of modified curing agent and 500 g of alkaline aggregate and place them in a reaction kettle. Heat to 50 °C, stir for 10 minutes to obtain Component B for standby.

[0101] S3. Prepare Component C

[0102] Weigh: 200 g of hydroxyl-terminated polybutadiene, 800 mL of ethyl acetate and 10 g of dibutyltin dilaurate and place them in a reaction kettle protected by a nitrogen atmosphere. Heat to 65 °C, add isophorone diisocyanate according to 2 times the total molar amount of hydroxyl groups of hydroxyl-terminated polybutadiene, hold the reaction for 3 h. After the reaction is completed, transfer the reaction solution to a rotary evaporator at 50 °C and rotate until no liquid is collected to obtain a modified epoxy resin precursor;

[0103] Weigh: 300 g of modified epoxy resin precursor, 15 g of dibutyltin dilaurate, 2000 mL of toluene and 500 g of bisphenol A epoxy resin and place them in a reaction kettle. Heat up to 90 °C and keep the temperature for reaction for 3 h. After the reaction is completed, add ethanol to the reaction solution, heat up to 110 °C, and carry out vacuum distillation until no liquid is drawn out to obtain the modified epoxy resin;

[0104] Weigh: 150 g of modified epoxy resin, 10 g of 2-hydroxy-2-methyl-1-phenyl-1-propanone and 25 of polyethylene glycol monooleate and place them in a reaction kettle, mix evenly to obtain Component C for standby.

[0105] S4. Prepare asphalt mixture

[0106] Weigh by weight: 100 parts of Component A and 70 parts of Component B and place them in a reaction kettle, stir for 6 min, add 60 parts of Component C, and stir at a speed of 4000 r / min for 8 min to obtain the cold patch asphalt mixture.

[0107] Comparative Example 1

[0108] The difference between this comparative example and Example 1 is that in step S1, the preparation of the modified nanocellulose aerogel is cancelled, and the modified nanocellulose aerogel is not added during the preparation of Component A in step S1.

[0109] Comparative Example 2

[0110] The difference between this comparative example and Example 1 is that in step S2, the preparation of the modified curing agent is cancelled, and 1,4-butanediamine in step S2 is used to replace the modified curing agent in the preparation of Component B in step S2 in equal amount.

[0111] Comparative Example 3

[0112] The difference between this comparative example and Example 1 is that in step S3, the preparation of the modified epoxy resin is cancelled, and the modified epoxy resin precursor in step S3 is used to replace the modified epoxy resin in the preparation of Component C in step S3 in equal amount;

[0113] Comparative Example 4

[0114] The difference between this comparative example and Example 1 is that when preparing Component B in step S2, the use of quicklime powder is cancelled.

[0115] Performance test:

[0116] Refer to the standard JT / T 1131-2017 "Cold Mix Resin Asphalt for Steel Bridge Deck Pavement" to test the curing time of the cold mix asphalt mixtures prepared in Examples 1-3 and Comparative Examples 1-4 at 25 °C;

[0117] The Marshall strength test was carried out on the cold mix asphalt mixtures prepared in Examples 1-3 and Comparative Examples 1-4 with reference to the standard DB23 / T 2600-2020 "Construction Technical Specification for High Modulus Asphalt Mixture Pavement".

[0118] With reference to the standard JT / T 1131-2017 "Cold Mix Resin Asphalt for Steel Bridge Deck Pavement", the high temperature resistance of the cured specimens of the cold mix asphalt mixtures prepared in Examples 1-3 and Comparative Examples 1-4 was tested after being used at 60 °C for 1 h. The specific data are shown in Table 1.

[0119] Table 1 - Performance Detection Table of Each Specimen

[0120]

[0121]

[0122] Data Analysis:

[0123] From the data analysis of Table 1 above, it can be seen that the curing time of the asphalt mixture specimen prepared by the present invention is 38 h. The initial strength of the asphalt mixture specimen was measured by the Marshall strength test to be 8.62 kN, the forming strength was 15.44 kN, there was no bulging after the cured specimen was tested at 60 °C for 1 h, the mass loss was 0.51%, and the tensile strength was 21.25 Mpa.

[0124] From the data analysis and comparison of Comparative Example 1 and Example 2, it can be seen that both the initial strength and the forming strength of the asphalt mixture specimen measured by the Marshall strength test decreased significantly, and there was bulging after the cured specimen was tested at 60 °C for 1 h, and both the mass loss and the tensile strength decreased. This shows that the present invention carboxylates nanocellulose, prepares carboxylated nanocellulose into a three-dimensional porous modified nanocellulose aerogel, and a large number of carboxyl groups on the surface of the carboxylated nanocellulose aerogel can form chemical crosslinks with the epoxy groups on the surface of the modified epoxy resin, improving the dispersion of nanocellulose in the modified epoxy resin, and enhancing the mechanical properties of the epoxy resin. At the same time, the hydroxyl groups on the surface of the modified nanocellulose aerogel can form hydrogen bonds with the hydroxyl groups on the molecular chain of the modified epoxy resin, improving the adhesion of the phase interface. When subjected to external forces, the material needs to absorb more energy, enhancing the toughness and strength of the asphalt mixture.

[0125] From the data analysis and comparison of Comparative Example 2 and Example 2, it can be seen that the curing time of the asphalt mixture is significantly increased, and there is no bulging after the cured specimen is tested at 60°C for 1 h. Both the mass loss and the tensile strength decrease. This shows that the modified curing agent of the present invention is prepared by the reaction of thiourea, 1,4-butanediamine and 2,4,6-tris(dimethylaminomethyl)phenol. The main components in the modified curing agent are three kinds: the polycondensation product I of thiourea and 1,4-butanediamine, and ammonium thiocyanate produced by the decomposition of thiourea in a high-temperature environment is product II. The thiourea molecule has a relatively large number of active hydrogens, which can not only improve the reaction activity and accelerate the reaction rate, but also reduce the curing temperature of the curing agent. And by modifying the polyamine with a thiourea group to introduce a mercapto group, the curing rate of the amine curing agent is significantly improved. On the other hand, part of the ammonium thiocyanate produced by the decomposition of thiourea reacts with 2,4,6-tris(dimethylaminomethyl)phenol to form product III. This product not only has the possibility of curing epoxy with cyanamide, but also has a very fast promoting effect on the curing reaction of the modified polyamine containing a mercapto group due to the presence of a tertiary amine structure itself, improving the curing time of the asphalt mixture and reducing the curing temperature;

[0126] From the data analysis and comparison of Comparative Example 3 and Example 2, it can be seen that the curing time of the asphalt mixture increases, and the initial strength and forming strength of the asphalt mixture specimen measured by the Marshall strength test both decrease significantly. And there is bulging after the cured specimen is tested at 60°C for 1 h. Both the mass loss and the tensile strength decrease. This shows that the present invention obtains a modified epoxy resin by end-capping and modifying hydroxyl-terminated polybutadiene with isophorone diisocyanate, and then cross-linking bisphenol A epoxy resin with the modified epoxy resin precursor by a nucleophilic addition reaction. The flexible long-chain structure of hydroxyl-terminated polybutadiene undergoes a ring-opening reaction with the epoxy group of the epoxy resin through the hydroxyl group at its end to form a cross-linked network. This cross-linked structure not only enhances the mechanical strength of the asphalt mixture, but also improves its elasticity and fatigue resistance. At the same time, the rigid benzene ring structure of bisphenol A epoxy resin provides good thermal stability and anti-deformation ability. At the same time, the unsaturated double bonds in hydroxyl-terminated polybutadiene can undergo a free radical polymerization reaction through a photoinitiator to form chemical cross-links with unsaturated bonds such as oleic acid in the diluent of the asphalt mixture, further enhancing the interfacial compatibility between the components of the asphalt mixture. This molecular-level synergistic effect makes the asphalt mixture have higher crack resistance, durability and anti-aging performance;

[0127] From the data analysis and comparison of Comparative Example 4 and Example 2, it can be seen that the curing time of the asphalt mixture increases, and there is no bulging after the cured specimen is tested at 60°C for 1 h. Both the mass loss and the tensile strength decrease. This shows that quicklime in the alkaline aggregate releases heat when encountering water during the preparation of the asphalt mixture, providing a heat source for the curing of the asphalt mixture and promoting the curing degree and curing time of the asphalt mixture.

[0128] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only the specific embodiments. Obviously, according to the content of this specification, many modifications and variations can be made. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A high-performance cold-patch asphalt mixture, characterized in that: The invention comprises the following components in parts by weight: 90-100 parts of component A, 60-70 parts of component B and 50-60 parts of component C; The A component is composed of matrix asphalt, modified nanocellulose aerogel and diluent in a dosage ratio of 200-250g:50-70g:60-80g; The B component is composed of a modified curing agent and an alkaline aggregate in a dosage ratio of 600-800g:400-500g; The C component is composed of modified epoxy resin, photoinitiator and surfactant in a dosage ratio of 100-150g:5-10g:20-25g.

2. A high performance cold patch asphalt mixture according to claim 1, characterized in that: The matrix asphalt is 70# asphalt, the diluent is diesel and oleic acid in a mass ratio of 1:1, the alkaline aggregate is composed of 2.5-5.0 mm gravel, 1-2 mm gravel and quicklime powder in a mass ratio of 1:1:2, the photoinitiator is 2-hydroxy-2-methyl-1-phenyl-1-propanone, and the surfactant is polyethylene glycol monooleate.

3. A high performance cold patch asphalt mixture according to claim 1, characterized in that: The modified nanocellulose aerogel is prepared by the following steps: A1, placing nanocellulose, N,N-dimethylformamide, 4-dimethylaminopyridine and triethylamine in a reaction kettle, ice bathing at 0-5°C, stirring for 30-60 minutes, adding succinic anhydride, heating to 40-50°C, and post-treating to obtain carboxylated nanocellulose; A2, placing carboxylated nanocellulose and deionized water in a three-necked flask, and ultrasonically dispersing for 30-60 minutes to obtain a nanocellulose mixed solution; A3. Inject the nanocellulose mixture into a silica gel mold, freeze for 1-2 hours, and freeze-dry to obtain modified nanocellulose aerogel.

4. A high performance cold patch asphalt mixture according to claim 3, characterized in that: In step A1, the amount ratio of the nanocellulose, N,N-dimethylformamide, 4-dimethylaminopyridine, triethylamine and succinic anhydride is 100-150g:1000-1500mL:30-40g:40-50g:60-70g; in step A2, the amount ratio of the carboxylated nanocellulose and deionized water is 100-200g:2000-4000mL; in step A3, the freeze-drying operation includes: placing the frozen nanocellulose solid in a freeze dryer at a temperature of -80--60°C and a pressure of 10-15Pa, and freeze-drying for 24-48h to obtain a modified nanocellulose aerogel.

5. The high-performance cold patch asphalt mixture according to claim 1, characterized in that: The preparation method of the modified curing agent comprises the following steps: placing thiourea, 1,4-butanediamine and 2,4,6-tris(dimethylaminomethyl)phenol in a reaction kettle, heating to 90-140° C., keeping the temperature for reaction for 40-60 minutes, and post-treating to obtain the modified curing agent.

6. A high performance cold patch asphalt mixture according to claim 5, characterized in that: The usage ratio of the thiourea, 1,4-butanediamine and 2,4,6-tris(dimethylaminomethyl)phenol is 300-600g:600-800g:1000-1200g.

7. The high performance cold patch asphalt mixture according to claim 1, characterized in that: The modified epoxy resin is prepared by the following steps: B1. Place terminal hydroxyl polybutadiene, ethyl acetate and dibutyltin diisocyanate in a reactor protected by a nitrogen atmosphere, heat to 45-65°C, add isophorone diisocyanate, keep the temperature for reaction for 2-3h, and post-treat to obtain a modified epoxy resin precursor; B2. Place the modified epoxy resin precursor, dibutyltin dilaurate, toluene and bisphenol A epoxy resin in a reaction kettle, heat to 80-90° C., keep the temperature for 2-3 hours, and post-treat to obtain the modified epoxy resin.

8. The high-performance cold patch asphalt mixture according to claim 7, characterized in that: In step B1, the amount of isophorone diisocyanate is twice the total molar amount of hydroxyl groups in the terminal hydroxyl polybutadiene, and the amount ratio of the terminal hydroxyl polybutadiene, ethyl acetate and dibutyltin diisocyanate is 100-200g:500-800mL:5-10g; in step B2, the amount ratio of the modified epoxy resin precursor, dibutyltin diisocyanate, toluene and bisphenol A epoxy resin is 200-300g:10-15g:1500-2000mL:400-500g.

9. A method for preparing a high-performance cold patch asphalt mixture according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. Place the matrix asphalt, modified nanocellulose aerogel and diluent in a reaction kettle, heat to 100-120° C., stir for 30-60 min, and obtain component A for standby use; S2. Place the modified curing agent and alkaline aggregate in a reaction kettle, heat to 40-50° C., stir for 5-10 minutes to obtain component B for standby use; S3, uniformly mixing the modified epoxy resin, the photoinitiator and the surfactant to obtain component C for standby use; S4. Place component A and component B in a reaction kettle, stir for 3-6 minutes, add component C, and stir at a speed of 3000-4000 r / min for 5-8 minutes to obtain a cold patch asphalt mixture.

10. An application of a high-performance cold patch asphalt mixture, characterized in that: A high-performance cold-patch asphalt mixture as described in any one of claims 1 to 8 is applied to road repair.

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