A composite modified asphalt and preparation method thereof

Abstract

The invention discloses a composite modified asphalt, which relates to the technical field of asphalt preparation. The composite modified asphalt is composed of the following materials: 70# matrix asphalt, graphene / hexagonal boron nitride composite modifier and boric acid; wherein the mass ratio of graphene to hexagonal boron nitride is 1:4, and the mass of the graphene / hexagonal boron nitride composite modifier is 0.3% of the mass of the 70# matrix asphalt. The graphene / hexagonal boron nitride composite modified asphalt prepared by the invention according to the optimized material formula improves its low temperature crack resistance and high temperature resistance when the graphene / hexagonal boron nitride composite modifier is added in an amount of 0.3%, and the performance of the graphene / hexagonal boron nitride composite modified asphalt is significantly improved.

Description

Technical Field

[0001] The invention relates to the technical field of asphalt preparation, in particular to a composite modified asphalt and a preparation method thereof. Background Art

[0002] Asphalt pavement accounts for the vast majority of all highway construction mileage. Due to factors such as increased traffic volume, larger vehicles, heavier vehicle loads, and temperature differences, rutting and cracking often occur on asphalt pavements, resulting in a decrease in the performance of asphalt pavements. Therefore, the transportation industry has put forward higher requirements on the performance and quality of asphalt pavements, hoping to accelerate the application and innovation of new materials and new technologies and reduce early damage to asphalt pavements and other diseases.

[0003] At present, the development of SBS modified asphalt has been the biggest contributor to the improvement of asphalt pavements. Practice has shown that adding SBS modifiers to base asphalt can significantly improve the high-temperature stability, fatigue resistance and temperature sensitivity of the pavement. However, in actual applications, SBS modified asphalt has problems such as high requirements for preparation conditions, unstable storage (easy to stratify, coagulate or segregate), and difficult mixing and construction, which leads to poor quality controllability of asphalt and asphalt mixtures, affecting the performance of asphalt pavements to a certain extent.

[0004] Graphene is a nanomaterial with a huge specific surface area and super strong surface activity. Experiments have shown that adding graphene to asphalt can have a special effect on the physical and chemical properties of asphalt, thereby comprehensively improving the performance of asphalt; however, in actual production, it is impossible to add graphene directly to asphalt: experiments show that when the amount of graphene added reaches a certain level, graphene will have serious agglomeration problems, and graphene cannot be evenly dispersed in the asphalt, resulting in the inability of graphene to modify the asphalt. Summary of the invention

[0005] The purpose of the present invention is to provide a composite modified asphalt and a preparation method thereof to solve the problems raised in the background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A composite modified asphalt is composed of the following materials: 70# base asphalt, graphene / hexagonal boron nitride composite modifier and boric acid; wherein the mass ratio of graphene to hexagonal boron nitride is 1:4, and the mass of the graphene / hexagonal boron nitride composite modifier is 0.3% of the mass of the 70# base asphalt.

[0008] On the basis of the above technical solution, the present invention also provides the following optional technical solution:

[0009] In an optional solution: the structure of the graphene / hexagonal boron nitride composite modifier is a layered structure with three layers.

[0010] A method for preparing a composite modified asphalt comprises the following steps:

[0011] Step S1: adding isopropanol solution and boric acid to the graphene / hexagonal boron nitride composite modifier to obtain a mixed solution A;

[0012] Step S2: in a sealed state, subjecting the mixed solution A to ultrasonic oscillation for 1.5 hours;

[0013] Step S3: adding trichloroethylene to the 70# base asphalt until the 70# base asphalt is completely dissolved to obtain a mixed solution B;

[0014] Step S4: adding mixed solution A to mixed solution B to obtain a mixture C, and subjecting the mixed solution C to ultrasonic oscillation treatment for 1 hour;

[0015] Step S5: using a rotary evaporator to evaporate the mixture C, evaporating trichloroethylene and isopropanol from the mixture C to obtain a mixture D;

[0016] Step S6: subjecting the mixture D to high-speed shearing to obtain high-performance graphene / hexagonal boron nitride composite modified asphalt.

[0017] In an optional solution: in step S5, the evaporation conditions are: oil bath temperature 110° C., rotation speed 85-90 rpm.

[0018] In an optional solution: in the step S6, the shear rate of the high-speed shearing is 6400 rpm, the shearing temperature is 140° C., and the shearing time is 180 minutes.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The graphene / hexagonal boron nitride composite modified asphalt prepared according to the optimized material formula of the present invention improves its low-temperature crack resistance and high-temperature resistance when the graphene / hexagonal boron nitride composite modifier is added in an amount of 0.3%, and the performance of the graphene / hexagonal boron nitride composite modified asphalt is significantly improved. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the present invention more clear, the embodiments listed in the present invention are only used to illustrate the present invention and are not used to limit the scope of the present invention. Any obvious modifications or changes made to the present invention do not deviate from the spirit and scope of the present invention.

[0022] The embodiment of the present invention discloses a composite modified asphalt, which is composed of the following materials: 70# base asphalt, graphene / hexagonal boron nitride composite modifier and boric acid; wherein the mass ratio of graphene to hexagonal boron nitride is 1:4, the mass of the graphene / hexagonal boron nitride composite modifier is 0.3% of the mass of the 70# base asphalt, and the structure of the graphene / hexagonal boron nitride composite modifier is a layered structure, and the number of layers is three.

[0023] The present invention discloses a method for preparing a composite modified asphalt, which comprises the following steps:

[0024] Step S1: adding isopropanol solution and boric acid to the graphene / hexagonal boron nitride composite modifier to obtain a mixed solution A;

[0025] Step S2: in a sealed state, subjecting the mixed solution A to ultrasonic oscillation for 1.5 hours;

[0026] Step S3: adding trichloroethylene to the 70# base asphalt until the 70# base asphalt is completely dissolved to obtain a mixed solution B;

[0027] Step S4: adding mixed solution A to mixed solution B to obtain a mixture C, and subjecting the mixed solution C to ultrasonic oscillation treatment for 1 hour;

[0028] Step S5: using a rotary evaporator to evaporate the mixture C, evaporating trichloroethylene and isopropanol from the mixture C to obtain a mixture D;

[0029] Step S6: subjecting the mixture D to high-speed shearing to obtain high-performance graphene / hexagonal boron nitride composite modified asphalt.

[0030] Wherein, in the step S5, the evaporation conditions are: oil bath temperature 110°C, rotation speed 85-90 rpm; in the step S6, the shear rate of the high-speed shearing is 6400 rpm, the shearing temperature is 140°C, and the shearing time is 180 minutes.

[0031] test:

[0032] A variety of surfactants and basic solvents (miscible with asphalt or easily separated from asphalt to observe the dispersion effect of graphene) were used for experiments, and finally an additive that can evenly disperse graphene was found - hexagonal boron nitride, and its corresponding basic solvent is isopropanol; in order to determine the best ratio of asphalt, surfactant and basic solvent and the best process conditions, the specific experiments are as follows:

[0033] The uniform design method is adopted to change the flake graphite content in the range of 1.0g to 4.0g, the hexagonal boron nitride content in the range of 1.0g to 4.0g, and the ball milling time in the range of 30 to 90 minutes;

[0034] Among them, the factor level table of the experimental design is shown in Table 1, the uniform design table is shown in Table 2, and the experimental arrangement is shown in Table 3.

[0035] Table 1

[0036]

[0037] Table 2

[0038]

[0039] Table 3

[0040]

[0041] The XRD characterization 26° peak values ​​of the ball milling products obtained in each test are shown in Table 4:

[0042] Table 4

[0043] Test No. 26° Accessory Peak 1 1269 2 3816 3 1392 4 2744 5 1927 6 681 7 665

[0044] The test data was analyzed using mathematical statistics software, and the obtained graphene / hexagonal boron nitride nanocomposite modifier material formula is shown in Table 5:

[0045] Table 5

[0046] Optimized solution Flake graphite content (g) Hexagonal boron nitride content (g) Ball milling time parameter 2.0 3.5 90

[0047] According to the graphene / hexagonal boron nitride nanocomposite modifier material formula, a graphene / hexagonal boron nitride nanocomposite modifier is prepared and a graphene / hexagonal boron nitride composite modified asphalt is prepared (the dosage of the graphene / hexagonal boron nitride composite modifier is determined to be 0.1%-0.5%). The performance indicators of the obtained graphene / hexagonal boron nitride composite modified asphalt are shown in Table 6:

[0048] Table 6

[0049]

[0050] As can be seen from Table 6, compared with the base asphalt, the graphene / hexagonal boron nitride composite modified asphalt prepared according to the optimized material formula, when the graphene / hexagonal boron nitride composite modifier dosage is 0.3%, its 5°C fracture energy (low temperature crack resistance) is increased by 1.7 times, and the 64°C anti-rutting factor (high temperature resistance) is increased by 1.7 times. The performance of the graphene / hexagonal boron nitride composite modified asphalt has been significantly improved. The above is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any technician familiar with the technical field can easily think of changes or replacements within the technical scope disclosed in the present disclosure, which should be covered within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be based on the protection scope of the claims.

Claims

1. A composite modified asphalt, characterized in that: The invention is composed of the following materials: 70# matrix asphalt, graphene / hexagonal boron nitride composite modifier and boric acid; wherein the material formula of the graphene / hexagonal boron nitride composite modifier is 2.0g of flake graphite and 3.5g of hexagonal boron nitride, and the mass of the graphene / hexagonal boron nitride composite modifier is 0.3% of the mass of the 70# matrix asphalt; The structure of the graphene / hexagonal boron nitride composite modifier is a layered structure with three layers.

2. A method for preparing the composite modified asphalt according to claim 1, characterized in that: The following steps are involved: Step S1: adding isopropanol solution and boric acid to the graphene / hexagonal boron nitride composite modifier to obtain a mixed solution A; Step S2: in a sealed state, subjecting the mixed solution A to ultrasonic oscillation for 1.5 hours; Step S3: adding trichloroethylene to the 70# base asphalt until the 70# base asphalt is completely dissolved to obtain a mixed solution B; Step S4: adding mixed solution A to mixed solution B to obtain a mixture C, and subjecting the mixed solution C to ultrasonic oscillation treatment for 1 hour; Step S5: using a rotary evaporator to evaporate the mixture C, evaporating trichloroethylene and isopropanol from the mixture C to obtain a mixture D; Step S6: subjecting the mixture D to high-speed shearing to obtain high-performance graphene / hexagonal boron nitride composite modified asphalt.

3. The method for preparing the composite modified asphalt according to claim 2, characterized in that: In step S5, the evaporation conditions are: oil bath temperature 110° C., rotation speed 85-90 rpm.

4. The method for preparing the composite modified asphalt according to claim 2, characterized in that: In step S6, the high-speed shearing has a shear rate of 6400 rpm, a shear temperature of 140° C., and a shear time of 180 minutes.

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