Modified asphalt and preparation method thereof

Abstract

The invention belongs to the technical field of asphalt materials, and particularly relates to modified asphalt and a preparation method thereof. The modified asphalt comprises the following raw materials in parts by weight: 90-100 parts of matrix asphalt; 10 to 15 parts of a styrene-butadiene-styrene block copolymer; 8 to 10 parts of modified polyacrylamide; 4-6 parts of modified polypropylene fiber; 3-5 parts of a compatilizer; 0.2 to 0.4 part of a stabilizing agent; according to the modified asphalt provided by the invention, the matrix asphalt is used as a main raw material, and the modified polyacrylamide and the modified polypropylene fiber are added for modification, so that the high-temperature resistance, the ultraviolet aging resistance and the low-temperature crack resistance of the modified asphalt are enhanced; therefore, the modified asphalt with good cohesiveness, high temperature resistance, low-temperature toughness, low-temperature crack resistance and ultraviolet aging resistance is prepared and is used for road construction, road diseases are reduced, and the service life is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of asphalt materials, and specifically relates to a modified asphalt and a preparation method thereof. Background Art

[0002] Asphalt is an important organic cementitious material, a dark brown complex mixture composed of hydrocarbons of different molecular weights and their non-metallic derivatives, existing in the form of viscous, black and highly viscous liquid or semi-solid. It has good waterproof and moisture-proof properties, corrosion resistance, adhesion, elasticity and plasticity, and is widely used in road construction, waterproof engineering, pipeline anti-corrosion and other fields. However, the road performance formed by the base asphalt used in road construction is poor. Under the long-term action of the natural environment and heavy-loaded vehicles, it is prone to road diseases such as rutting, cracking, loosening, and peeling, which affect driving safety and the service life of the road. With the continuous development of the field of road construction, higher requirements are also placed on the performance of asphalt materials. Modifiers such as rubber, resin, high molecular polymer, ground rubber powder or other fillers are usually added to asphalt for modification to obtain modified asphalt materials with better performance.

[0003] The Chinese patent application number CN202211523286.2 provides a nano-doped zinc oxide modified asphalt and a preparation method thereof. The nano-doped zinc oxide modified asphalt is made of the following raw materials in parts by weight: 100 parts asphalt, 2.74-14.28 parts of mixed salt, 38.67-201.68 parts of deionized water, and 1.70-8.87 parts of oxalic acid. The mixed salt is prepared by mixing salt A and salt B in a molar ratio of 9:1. Salt A is zinc acetate, and salt B is magnesium acetate or aluminum nitrate. The patent increases the reaction energy barrier of asphalt molecules into high-energy free radicals by doping nano-zinc oxide, slows down the oxidation of asphalt molecules, and improves the quality of the asphalt. The asphalt has better anti-ultraviolet aging performance; the Chinese patent with application number CN202411379632.3 provides an aging-resistant polyurethane-zirconium phosphate composite modified asphalt and its preparation method. The polyurethane-zirconium phosphate composite modified asphalt includes components in parts by weight: 100 parts of base asphalt, 3-15 parts of isocyanate prepolymer, 1-8 parts of organic zirconium phosphate, 0.001-0.1 parts of catalyst and 2-5 parts of solubilizer, wherein the organic zirconium phosphate is prepared by ultrasonic intercalation treatment of zirconium phosphate with organic molecules. It has a polyurethane cross-linked network structure and a layered structure, which can effectively improve the high and low temperature performance and anti-aging performance of asphalt.

[0004] The above patents all modify asphalt. Although the anti-aging performance of asphalt has been improved to a certain extent, the comprehensive performance of the modified asphalt still cannot meet market demand. Summary of the invention

[0005] The purpose of the present invention is to provide a modified asphalt and a preparation method thereof in view of the deficiencies in the prior art. The present invention uses base asphalt as the main raw material, adds modified polyacrylamide and modified polypropylene fiber for modification, and enhances the high temperature resistance, anti-ultraviolet aging performance, and low temperature crack resistance of the modified asphalt, thereby obtaining a modified asphalt with good adhesion, high temperature resistance, low temperature toughness, low temperature crack resistance, and anti-ultraviolet aging performance. The modified asphalt is used for road construction, reduces road diseases, and prolongs its service life.

[0006] The technical solution adopted by the present invention to achieve the above-mentioned purpose is: A modified asphalt comprises the following raw materials in parts by weight: 90-100 parts of base asphalt; 10-15 parts of styrene-butadiene-styrene block copolymer; 8-10 parts of modified polyacrylamide; 4-6 parts of modified polypropylene fiber; 3-5 parts of compatibilizer; and 0.2-0.4 parts of stabilizer.

[0007] Furthermore, the base asphalt is No. 70 asphalt or No. 90 asphalt.

[0008] Furthermore, the compatibilizer is castor oil or palm oil.

[0009] Furthermore, the stabilizer is sulfur or tetramethylthiuram disulfide.

[0010] In the technical scheme of the present invention, the preparation method of the modified polyacrylamide is: add water, acrylamide, methyl methacrylate, and a modified antioxidant into a reaction bottle, stir evenly, protect with nitrogen, and dropwise add a 50-60wt% aqueous solution of ammonium persulfate at a temperature of 70-75°C. After the dropwise addition, continue the reaction for 3.5-4h to obtain the modified polyacrylamide.

[0011] Furthermore, the mass ratio of acrylamide, methyl methacrylate, modified antioxidant and water is 10:4-5:3-4:20-25; the amount of ammonium persulfate used is 0.5-0.6% of the total mass of acrylamide, methyl methacrylate and modified antioxidant.

[0012] In the technical solution of the present invention, the preparation method of the modified polypropylene fiber is: add xylene and polypropylene fiber into a reaction bottle, stir evenly, add benzoyl peroxide and a modified antioxidant, stir and react for 3-4 hours at a temperature of 100-110°C to obtain the modified polypropylene fiber.

[0013] Furthermore, the mass ratio of the polypropylene fiber, the modified antioxidant and the benzoyl peroxide is 1:0.3-0.4:0.06-0.08.

[0014] In the technical scheme of the present invention, the modified antioxidants described in the preparation methods of modified polyacrylamide and modified polypropylene fiber are prepared by reacting 6-chloro-1-hydroxybenzotriazole with diethylphosphite chloride and diallylamine. The preparation method is: add anhydrous chloroform, 6-chloro-1-hydroxybenzotriazole and triethylamine to a reaction bottle, place the reaction bottle in an ice bath, slowly drop diethylphosphite chloride while stirring, continue to stir and react for 2-3 hours, then naturally warm to room temperature, add diallylamine, continue to heat to 50-60°C, stir and react for 4-5 hours, and obtain the modified antioxidant.

[0015] Furthermore, the molar ratio of the 6-chloro-1-hydroxybenzotriazole, diethylphosphite chloride, diallylamine and triethylamine is 1:1-1.1:1.1-1.2:1.6-1.8.

[0016] The present invention also provides a method for preparing modified asphalt, comprising the following steps: firstly heating the base asphalt to 170-180°C according to the mass ratio, then adding styrene-butadiene-styrene block copolymer, modified polyacrylamide, modified polypropylene fiber, a compatibilizer and a stabilizer, mixing evenly, and then performing high-speed shearing to obtain the modified asphalt.

[0017] Furthermore, the shearing speed is 4000-5000 r / min, and the shearing time is 1-1.5 h.

[0018] The present invention has the following beneficial effects: 1. The present invention uses 6-chloro-1-hydroxybenzotriazole as a raw material, and reacts with diethylphosphite chloride and diallylamine in sequence under the action of triethylamine to obtain a modified antioxidant. The modified antioxidant structure contains diallyl, benzotriazole group and phosphite group, wherein the benzotriazole group has a good absorption effect on ultraviolet rays and can effectively prevent the aging of the material. The phosphite group has good high temperature resistance and can effectively enhance the high temperature resistance of the material. The presence of diallyl makes the modified antioxidant easy to undergo free radical polymerization reaction, and then the modified antioxidant is used for modified polyacrylamide and modified polypropylene fiber modification.

[0019] 2. The present invention utilizes the diallyl group in the structure of the modified antioxidant to polymerize the modified antioxidant with acrylamide and methyl methacrylate under the catalytic action of ammonium persulfate to obtain a modified polyacrylamide with a network structure. The active amino group in its molecular structure can also enhance the binding force with the asphalt raw material, which helps to improve the comprehensive performance of the modified asphalt. The modified antioxidant introduced into its molecular structure can also enhance the high temperature resistance and UV aging resistance of the modified asphalt.

[0020] 3. The present invention also utilizes the diallyl group in the structure of the modified antioxidant to react with the polypropylene fiber under the catalytic action of benzoyl peroxide, and grafts the modified antioxidant onto the polypropylene fiber to obtain modified polypropylene fiber. The modified polypropylene fiber can enhance the low-temperature crack resistance of the modified asphalt, and the grafted modified antioxidant can also enhance the high temperature resistance and UV aging resistance of the modified asphalt.

[0021] 4. The modified asphalt provided by the present invention uses base asphalt as the main raw material, and is modified by adding modified polyacrylamide and modified polypropylene fiber to enhance the high temperature resistance, UV aging resistance and low temperature crack resistance of the modified asphalt, thereby obtaining a modified asphalt with good adhesion, high temperature resistance, low temperature toughness, low temperature crack resistance and UV aging resistance. The modified asphalt is used for road construction, reduces road diseases and prolongs its service life. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; the technical features designed in different implementation modes of the present invention described below can be combined with each other as long as they do not conflict with each other; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0023] In the technical scheme of the present invention, the chemical reagents used are all commercially available, wherein the ratio of styrene to butadiene blocks in styrene-butadiene-styrene block copolymer is 30:70; castor oil CAS No. 8001-79-4, palm oil CAS No. 8002-75-3, sulfur CAS No. 7704-34-9, tetramethylthiuram disulfide CAS No. 137-26-8, acrylamide CAS No. 79-06-1, methyl methacrylate CAS No. 80-62-6, ammonium persulfate CAS No. 7727-54-0, The diameter of the polypropylene fiber is 10-20 μm and the length is 3-5 mm; benzoyl peroxide CAS No. 94-36-0, 6-chloro-1-hydroxybenzotriazole CAS No. 26198-19-6, diethylphosphite chloride CAS No. 589-57-1, diallylamine CAS No. 124-02-7, triethylamine CAS No. 121-44-8, xylene CAS No. 1330-20-7, dichloromethane CAS No. 75-09-2, acetone CAS No. 67-64-1, chloroform CAS No. 67-66-3.

[0024] Embodiment 1 This embodiment provides a method for preparing a modified antioxidant. The present invention prepares the modified antioxidant by reacting 6-chloro-1-hydroxybenzotriazole with diethylphosphite chloride and diallylamine. The reaction route is: ; The preparation method is as follows: 900 mL of anhydrous chloroform, 30.0 g of 6-chloro-1-hydroxybenzotriazole and 32.2 g of triethylamine are added to a reaction bottle, the reaction bottle is placed in an ice bath, 29.1 g of diethylphosphite chloride is slowly added dropwise while stirring, after the addition is completed, stirring and reacting for 2.5 hours, then the temperature is naturally raised to room temperature, 18.9 g of diallylamine is added, the temperature is continued to be raised to 60° C., stirring and reacting for 5 hours, after the reaction is completed, chloroform is removed, and extraction is performed with water and dichloromethane, and the organic phase is concentrated under reduced pressure to obtain 46.3 g of a modified antioxidant; wherein the molar ratio of 6-chloro-1-hydroxybenzotriazole, diethylphosphite chloride, diallylamine and triethylamine is 1:1.05:1.1:1.8; modified antioxidant: ESI (m / z): 351.2 [M+H] + , 1 H-NMR (600 MHz, DMSO-d 6 , δppm): 7.84 (d, J=8.7Hz, 1H), 7.35 (s, 1H), 6.78 (d, J=8.7Hz, 1H), 5.82- 5.89 (m, 2H), 5.20-5.32 (m, 4H), 3.81-3.97 (m, 8H), 1.29 (t, J=7.3Hz, 6H).

[0025] Embodiment 2 A modified asphalt comprises the following raw materials in parts by weight: 100 parts of base asphalt; 13 parts of styrene-butadiene-styrene block copolymer; 10 parts of modified polyacrylamide; 6 parts of modified polypropylene fiber; 5 parts of compatibilizer; 0.4 parts of stabilizer; wherein the base asphalt is No. 70 asphalt; the compatibilizer is castor oil; and the stabilizer is sulfur.

[0026] The preparation method of modified polyacrylamide is as follows: add water, acrylamide, methyl methacrylate and modified antioxidant into a reaction bottle, stir evenly, protect with nitrogen, add 60wt% ammonium persulfate aqueous solution dropwise at a temperature of 75°C, continue to react for 3.5h after the addition is complete, cool and filter after the reaction is completed, wash the product with water and acetone in turn, and obtain modified polyacrylamide after drying; wherein the mass ratio of acrylamide, methyl methacrylate, modified antioxidant and water is 10:5:4:25; the amount of ammonium persulfate used is 0.6% of the total mass of acrylamide, methyl methacrylate and modified antioxidant.

[0027] The preparation method of modified polypropylene fiber is as follows: add xylene and polypropylene fiber into a reaction bottle, stir evenly, add benzoyl peroxide and modified antioxidant, stir and react for 3 hours at a temperature of 110°C, cool and filter after the reaction is completed, wash the product with xylene and acetone in turn, and obtain modified polypropylene fiber after drying; wherein the mass ratio of polypropylene fiber, modified antioxidant and benzoyl peroxide is 1:0.4:0.08.

[0028] A method for preparing modified asphalt comprises the following steps: firstly heating a base asphalt to 180°C according to a mass ratio, then adding styrene-butadiene-styrene block copolymer, modified polyacrylamide, modified polypropylene fiber, a compatibilizer and a stabilizer, mixing evenly, and then performing high-speed shearing to obtain the modified asphalt; wherein the shearing speed is 5000 r / min and the shearing time is 1 hour.

[0029] Embodiment 3 A modified asphalt, the modified asphalt comprises the following raw materials in parts by weight: 95 parts of base asphalt; 15 parts of styrene-butadiene-styrene block copolymer; 9 parts of modified polyacrylamide; 5 parts of modified polypropylene fiber; 4 parts of compatibilizer; 0.3 parts of stabilizer; wherein the base asphalt is No. 90 asphalt; the compatibilizer is palm oil; and the stabilizer is tetramethylthiuram disulfide.

[0030] The preparation method of modified polyacrylamide is as follows: add water, acrylamide, methyl methacrylate and modified antioxidant into a reaction bottle, stir evenly, protect with nitrogen, dropwise add 55wt% ammonium persulfate aqueous solution at a temperature of 70°C, continue to react for 4h after the dropwise addition, cool and filter after the reaction is completed, wash the product with water and acetone in turn, and obtain modified polyacrylamide after drying; wherein the mass ratio of acrylamide, methyl methacrylate, modified antioxidant and water is 10:4:3:20; the amount of ammonium persulfate used is 0.5% of the total mass of acrylamide, methyl methacrylate and modified antioxidant.

[0031] The preparation method of modified polypropylene fiber is as follows: add xylene and polypropylene fiber into a reaction bottle, stir evenly, add benzoyl peroxide and modified antioxidant, stir and react for 4 hours at a temperature of 100°C, cool and filter after the reaction is completed, wash the product with xylene and acetone in turn, and obtain modified polypropylene fiber after drying; wherein the mass ratio of polypropylene fiber, modified antioxidant and benzoyl peroxide is 1:0.3:0.06.

[0032] A method for preparing modified asphalt comprises the following steps: firstly heating a base asphalt to 170°C according to a mass ratio, then adding styrene-butadiene-styrene block copolymer, modified polyacrylamide, modified polypropylene fiber, a compatibilizer and a stabilizer, mixing evenly, and then performing high-speed shearing to obtain the modified asphalt; wherein the shearing speed is 4000 r / min, and the shearing time is 1.5 h.

[0033] Embodiment 4 A modified asphalt comprises the following raw materials in parts by weight: 90 parts of base asphalt; 10 parts of styrene-butadiene-styrene block copolymer; 8 parts of modified polyacrylamide; 4 parts of modified polypropylene fiber; 3 parts of compatibilizer; and 0.2 parts of stabilizer; wherein the base asphalt is No. 90 asphalt; the compatibilizer is castor oil; and the stabilizer is tetramethylthiuram disulfide.

[0034] The preparation method of modified polyacrylamide is as follows: add water, acrylamide, methyl methacrylate and modified antioxidant into a reaction bottle, stir evenly, protect with nitrogen, add 50wt% ammonium persulfate aqueous solution dropwise at a temperature of 73°C, continue to react for 3.8h after the dropwise addition, cool and filter after the reaction is completed, wash the product with water and acetone in turn, and obtain modified polyacrylamide after drying; wherein the mass ratio of acrylamide, methyl methacrylate, modified antioxidant and water is 10:4.5:3.5:22; the amount of ammonium persulfate used is 0.55% of the total mass of acrylamide, methyl methacrylate and modified antioxidant.

[0035] The preparation method of modified polypropylene fiber is as follows: add xylene and polypropylene fiber into a reaction bottle, stir evenly, add benzoyl peroxide and modified antioxidant, stir and react for 3.5 hours at a temperature of 105°C, cool and filter after the reaction is completed, wash the product with xylene and acetone in turn, and obtain modified polypropylene fiber after drying; wherein the mass ratio of polypropylene fiber, modified antioxidant and benzoyl peroxide is 1:0.35:0.07.

[0036] A method for preparing modified asphalt comprises the following steps: firstly heating a base asphalt to 175°C according to a mass ratio, then adding styrene-butadiene-styrene block copolymer, modified polyacrylamide, modified polypropylene fiber, a compatibilizer and a stabilizer, mixing evenly, and then performing high-speed shearing to obtain the modified asphalt; wherein the shearing speed is 4500 r / min, and the shearing time is 1.3 h.

[0037] Embodiment 5 A modified asphalt comprises the following raw materials in parts by weight: 95 parts of base asphalt; 15 parts of styrene-butadiene-styrene block copolymer; 10 parts of modified polyacrylamide; 5 parts of modified polypropylene fiber; 4 parts of compatibilizer; 0.4 parts of stabilizer; wherein the base asphalt is No. 70 asphalt; the compatibilizer is palm oil; and the stabilizer is sulfur.

[0038] The preparation method of modified polyacrylamide is as follows: add water, acrylamide, methyl methacrylate and modified antioxidant into a reaction bottle, stir evenly, protect with nitrogen, dropwise add 50wt% ammonium persulfate aqueous solution at a temperature of 75°C, continue to react for 4h after the dropwise addition, cool and filter after the reaction is completed, wash the product with water and acetone in turn, and obtain modified polyacrylamide after drying; wherein the mass ratio of acrylamide, methyl methacrylate, modified antioxidant and water is 10:5:3:25; the amount of ammonium persulfate used is 0.5% of the total mass of acrylamide, methyl methacrylate and modified antioxidant.

[0039] The preparation method of modified polypropylene fiber is as follows: add xylene and polypropylene fiber into a reaction bottle, stir evenly, add benzoyl peroxide and modified antioxidant, stir and react for 3.5 hours at a temperature of 100°C, cool and filter after the reaction is completed, wash the product with xylene and acetone in turn, and obtain modified polypropylene fiber after drying; wherein the mass ratio of polypropylene fiber, modified antioxidant and benzoyl peroxide is 1:0.4:0.07.

[0040] A method for preparing modified asphalt comprises the following steps: firstly heating a base asphalt to 180°C according to a mass ratio, then adding styrene-butadiene-styrene block copolymer, modified polyacrylamide, modified polypropylene fiber, a compatibilizer and a stabilizer, mixing evenly, and then performing high-speed shearing to obtain the modified asphalt; wherein the shearing speed is 4500 r / min, and the shearing time is 1.5 h.

[0041] Comparative Example 1 Compared with Example 2, the raw material of the modified asphalt in this comparative example does not contain modified polyacrylamide.

[0042] A modified asphalt comprises the following raw materials in parts by weight: 100 parts of base asphalt; 13 parts of styrene-butadiene-styrene block copolymer; 6 parts of modified polypropylene fiber; 5 parts of compatibilizer; and 0.4 parts of stabilizer. The base asphalt is No. 70 asphalt; the compatibilizer is castor oil; and the stabilizer is sulfur.

[0043] The preparation method of the modified polypropylene fiber is the same as that of Example 2.

[0044] A method for preparing modified asphalt comprises the following steps: firstly heating a base asphalt to 180°C according to a mass ratio, then adding styrene-butadiene-styrene block copolymer, modified polypropylene fiber, a compatibilizer and a stabilizer, mixing them evenly, and then performing high-speed shearing to obtain the modified asphalt; wherein the shearing speed is 5000 r / min and the shearing time is 1 hour.

[0045] Comparative Example 2 Compared with Example 2, the raw material of the modified asphalt in this comparative example does not contain modified polypropylene fiber.

[0046] A modified asphalt comprises the following raw materials in parts by weight: 100 parts of base asphalt; 13 parts of styrene-butadiene-styrene block copolymer; 10 parts of modified polyacrylamide; 5 parts of compatibilizer; and 0.4 parts of stabilizer; wherein the base asphalt is No. 70 asphalt; the compatibilizer is castor oil; and the stabilizer is sulfur.

[0047] The preparation method of modified polyacrylamide is the same as that of Example 2.

[0048] A method for preparing modified asphalt comprises the following steps: firstly heating a base asphalt to 180°C according to a mass ratio, then adding styrene-butadiene-styrene block copolymer, modified polyacrylamide, a compatibilizer and a stabilizer, mixing evenly, and then high-speed shearing to obtain the modified asphalt; wherein the shearing speed is 5000 r / min and the shearing time is 1 hour.

[0049] Comparative Example 3 Compared with Example 2, the raw materials of the modified asphalt in this comparative example do not contain modified polyacrylamide and modified polypropylene fiber.

[0050] A modified asphalt comprises the following raw materials in parts by weight: 100 parts of base asphalt; 13 parts of styrene-butadiene-styrene block copolymer; 5 parts of compatibilizer; and 0.4 parts of stabilizer. The base asphalt is No. 70 asphalt; the compatibilizer is castor oil; and the stabilizer is sulfur.

[0051] A method for preparing modified asphalt comprises the following steps: firstly heating a base asphalt to 180°C according to a mass ratio, then adding a styrene-butadiene-styrene block copolymer, a compatibilizer and a stabilizer, mixing them evenly, and then performing high-speed shearing to obtain the modified asphalt; wherein the shearing speed is 5000 r / min and the shearing time is 1 hour.

[0052] Performance test of modified asphalt The modified asphalts prepared in Examples 2 to 5 and Comparative Examples 1 to 3 were subjected to performance tests, wherein the softening point test was conducted in accordance with GB / T 4507 standard, using the ring and ball method to test the softening point of the sample; the penetration test was conducted in accordance with GB / T 4509 standard, under the test conditions of 25°C, 100g, 5s; the ductility test was conducted in accordance with GB / T 4508 standard, under the test conditions of 5°C; the aging resistance was conducted in accordance with JTG E20-2011 standard, under the aging conditions of UV light intensity of 800W / m 2 , temperature is 60℃, aging time is 72h; low temperature crack resistance test refers to JTG F40-2004 standard, and the low temperature maximum bending and tensile strain of the test sample is tested; high temperature resistance test refers to JTGE20-2011 standard, and the rutting factor of the test sample before and after high temperature treatment is tested. The high temperature treatment conditions are: at a temperature of 65℃, high temperature treatment for 2h, rutting factor high temperature index = (rutting factor after high temperature treatment - rutting factor before high temperature treatment) / rutting factor before high temperature treatment × 100%. The smaller the high temperature index of the rutting factor, the better the high temperature resistance of the sample; the performance test results are shown in Table 1.

[0053] Table 1 Performance test results sample Softening point / ℃ 25℃ Needle penetration / 0.1mm 5℃ elongation / cm Aging Index Low temperature maximum bending strain / με Rutting factor high temperature index / % Embodiment 2 85 40 38 0.006 3294 1248 Embodiment 3 82 43 41 0.008 3588 1324 Embodiment 4 81 45 40 0.009 3465 1386 Embodiment 5 84 41 37 0.007 3240 1205 Comparative Example 1 70 59 31 0.019 2745 1652 Comparative Example 2 73 55 28 0.015 1950 1514 Comparative Example 3 65 68 25 0.024 1485 1740 From the results in Table 1, it can be seen that the modified asphalts prepared in Examples 2 to 5 of the present invention have higher softening point, low-temperature ductility, low-temperature maximum bending strain and lower needle penetration, aging index, rutting factor high-temperature index, indicating that the modified asphalt prepared in the present invention has good adhesion, high temperature resistance, low-temperature toughness, low-temperature crack resistance and ultraviolet aging resistance; compared with Comparative Examples 1 to 3, the modified asphalt raw material of Example 2 of the present invention contains modified polyacrylamide and modified polypropylene fiber, and the structures of modified polyacrylamide and modified polypropylene fiber both contain benzotriazole groups and phosphite groups. The benzotriazole group can enhance the ultraviolet aging resistance of the modified asphalt, and the phosphite group can enhance the high temperature resistance of the modified asphalt. The active group amino contained in the modified polyacrylamide structure can enhance its bonding with the asphalt raw material, which is helpful to improve the comprehensive performance of the modified asphalt, and the modified polypropylene fiber can also enhance the low-temperature crack resistance of the modified asphalt.

[0054] It should be noted that, in this article, terms such as "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0055] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A modified asphalt, characterized in that: The modified asphalt comprises the following raw materials in parts by weight: 90-100 parts of base asphalt; 10-15 parts of styrene-butadiene-styrene block copolymer; 8-10 parts of modified polyacrylamide; 4-6 parts of modified polypropylene fiber; 3-5 parts of compatibilizer; and 0.2-0.4 parts of stabilizer. The preparation method of the modified polyacrylamide is as follows: water, acrylamide, methyl methacrylate, and a modified antioxidant are added to a reaction bottle, stirred evenly, and nitrogen protection is applied. At a temperature of 70-75° C., a 50-60 wt % aqueous solution of ammonium persulfate is added dropwise, and after the addition is completed, the reaction is continued for 3.5-4 hours to obtain the modified polyacrylamide; The preparation method of the modified polypropylene fiber is as follows: add xylene and polypropylene fiber into a reaction bottle, stir evenly, add benzoyl peroxide and a modified antioxidant, stir and react at a temperature of 100-110° C. for 3-4 hours to obtain the modified polypropylene fiber; In the preparation method of modified polyacrylamide and modified polypropylene fiber, the modified antioxidant is prepared by the reaction of 6-chloro-1-hydroxybenzotriazole with diethylphosphite chloride and diallylamine.

2. A modified asphalt according to claim 1, characterized in that: The preparation method of the modified antioxidant is as follows: anhydrous chloroform, 6-chloro-1-hydroxybenzotriazole and triethylamine are added to a reaction bottle, the reaction bottle is placed in an ice bath, diethylphosphite chloride is slowly added dropwise while stirring, after the addition is completed, stirring and reacting for 2-3 hours, then naturally warming to room temperature, adding diallylamine, continuing to heat to 50-60° C., stirring and reacting for 4-5 hours, and obtaining the modified antioxidant.

3. A modified asphalt according to claim 2, characterized in that: The molar ratio of the 6-chloro-1-hydroxybenzotriazole, diethylphosphite chloride, diallylamine and triethylamine is 1:1-1.1:1.1-1.2:1.6-1.

8.

4. A modified asphalt according to claim 1, characterized in that: In the preparation method of modified polyacrylamide, the mass ratio of acrylamide, methyl methacrylate, modified antioxidant and water is 10:4-5:3-4:20-25; the amount of ammonium persulfate used is 0.5-0.6% of the total mass of acrylamide, methyl methacrylate and modified antioxidant.

5. The modified asphalt according to claim 1, characterized in that: In the preparation method of modified polypropylene fiber, the mass ratio of the polypropylene fiber, the modified antioxidant and benzoyl peroxide is 1:0.3-0.4:0.06-0.

08.

6. The modified asphalt according to claim 1, characterized in that: The matrix asphalt is No. 70 asphalt or No. 90 asphalt.

7. The modified asphalt according to claim 1, characterized in that: The compatibilizer is castor oil or palm oil.

8. The modified asphalt according to claim 1, characterized in that: The stabilizer is sulfur or tetramethylthiuram disulfide.

9. A method for preparing modified asphalt according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: firstly heating the base asphalt to 170-180°C according to the mass ratio, then adding styrene-butadiene-styrene block copolymer, modified polyacrylamide, modified polypropylene fiber, compatibilizer and stabilizer, mixing evenly, and performing high-speed shearing to obtain modified asphalt.

10. The method for preparing modified asphalt according to claim 9, characterized in that: The shearing speed is 4000-5000 r / min, and the shearing time is 1-1.5 h.