CN113773663B - Asphalt and asphalt mixture containing modified nano-graphene oxide - Google Patents

Abstract

The invention relates to asphalt containing modified nano graphene oxide, which comprises matrix asphalt and modified nano graphene oxide accounting for 0.03-0.06% of the mass of the matrix asphalt, wherein the modified nano graphene oxide is prepared by mixing polyvinylpyrrolidone and nano graphene oxide powder in a mass ratio of 1: (5-6) mixing and preparing. According to the product provided by the invention, a certain amount of nano graphene oxide prepared by a specific method is added into conventional matrix asphalt, so that the comprehensive performance of the asphalt can be comprehensively improved, and the product is more suitable for being used in an extreme environment.

Description

Asphalt and asphalt mixture containing modified nano-graphene oxide

technical field

The invention relates to the technical field of road engineering materials, in particular to asphalt and asphalt mixture containing modified nanometer graphene oxide.

Background technique

With the development of the economy and the increase of traffic demand, the traffic volume and axle load in our country are increasing year by year. At the same time, with the change of global climate, extreme meteorological events have occurred frequently in recent years, such as ultra-high temperature weather, rain, snow and frost. Most roads in our country use asphalt pavement, but in the face of complex road conditions and natural environment, unmodified asphalt can no longer bear the increasing axle load and harsh weather environment, which seriously affects the service life of asphalt pavement. Therefore, there is an urgent need to develop new asphalt materials to enhance the performance of road asphalt pavement to ensure its longer service life under complex and severe service conditions.

In the prior art, nanometer graphene oxide is used to improve the performance of asphalt. However, due to the large specific surface area and high surface energy of nano-graphene oxide, spontaneous agglomeration often occurs and cannot be well dispersed in asphalt, which greatly reduces the modification effect of nano-graphene oxide on asphalt. Although the method of heating asphalt to reduce viscosity, strong shear stirring or adding dispersant can be used to improve the dispersion of nanomaterials in asphalt, but the effect is not significant.

At present, it is urgent to develop an asphalt and asphalt mixture with excellent comprehensive performance and good application effect.

Contents of the invention

The first object of the present invention is to provide a pitch containing modified nanometer graphene oxide. The asphalt provided by the invention has excellent comprehensive properties, and has good effects in temperature sensitivity, viscosity, plasticity, aging resistance and the like.

Specifically, the asphalt containing modified nano-graphene oxide provided by the present invention comprises base asphalt and modified nano-graphene oxide accounting for 0.03-0.06% of the mass of the base asphalt.

In some embodiments of the present invention, the mass of the modified nano-graphene oxide accounts for 0.04-0.05% of the mass of the base pitch.

In some embodiments of the present invention, the base asphalt is No. 70 base asphalt. The modified nano-graphene oxide provided by the invention can be well dispersed in the base asphalt, especially can exert the best synergistic effect with the No. 70 base asphalt, so as to obtain the asphalt with excellent comprehensive performance.

The modified nano-graphene oxide of the present invention is prepared by the method comprising the following steps:

(1) Graphite is mixed with concentrated sulfuric acid and phosphoric acid, and potassium permanganate is slowly added, and the reaction is stirred;

(2) Add deionized water to the reaction solution obtained in step (1), then add hydrogen peroxide solution to react, repeatedly wash and centrifuge the gained reaction product, make graphite oxide peel off and form nano-graphene oxide gel, dry to obtain Nano graphene oxide powder;

(3) Mix polyvinylpyrrolidone (PVP) aqueous solution with the nano-graphene oxide powder, wherein the mass ratio of polyvinylpyrrolidone and nano-graphene oxide powder is 1: (5-6), ultrasonically disperse evenly, and stir to react, Wash and dry.

In some embodiments of the present invention, the stirring reaction in step (1) is carried out sequentially in an ice bath, a water bath at 30-50°C and a water bath at 80-95°C. Under the above conditions, it is possible to ensure the formation of nano-graphene oxide with suitable and uniform particle size.

In some embodiments of the present invention, the repeated washing in step (2) uses an acidic aqueous solution, preferably an aqueous solution with a pH value of 5.3-5.7. Under the above conditions, it is possible to ensure the formation of nano-graphene oxide with suitable and uniform particle size.

The present invention limits the mass ratio of polyvinylpyrrolidone in the polyvinylpyrrolidone aqueous solution in step (3) to the nano-graphene oxide powder to be 1: (5-6), more preferably 1:5.5. In the present invention, by optimizing the mass ratio of polyvinylpyrrolidone to the nano-graphene oxide powder, it can be ensured that the nano-graphene oxide powder modified by polyvinylpyrrolidone is dispersed in the matrix asphalt in the best state and degree of dispersion. They work together to produce the best modification effect on base asphalt, especially No. 70 base asphalt.

In some embodiments of the present invention, the stirring reaction in step (3) is first carried out at 32-38°C and pH 7.6-8, and then at 25-30°C and pH 6.8-7.2 . In the present invention, by optimizing the conditions during the mixed reaction between polyvinylpyrrolidone and the nano-graphene oxide powder, it can ensure that the particle size of the nano-graphene oxide powder modified by a specific proportion of polyvinylpyrrolidone is more uniform and the properties are more stable. So as to produce the best modification effect on the base asphalt.

In some embodiments of the present invention, the modified nano-graphene oxide powder is prepared by a method comprising the following specific steps:

(1) Mix 0.15 parts of graphite with 34 parts of concentrated sulfuric acid and 3 parts of concentrated phosphoric acid, mechanically stir in an ice bath for 10 minutes, slowly add 0.9 parts of potassium permanganate, keep the temperature at 0°C, and stir the reaction in an ice bath 2 hours, then stirred and reacted in a 40°C water bath for 60 minutes, then adjusted the temperature of the water bath to 95°C and stirred for 60 minutes;

(2) Suspend the reaction product obtained in step (1) in water, add 11 parts of hydrogen peroxide to react, the reaction product is repeatedly washed and centrifuged for 5 times with an aqueous solution of pH 5.5, and the graphite oxide is peeled off during the washing process to form nano-graphite oxide Graphene gel, dried at 60°C to obtain nano-graphene oxide powder;

(3) Add the nano-graphene oxide powder obtained in step (2) to the PVP aqueous solution, wherein the mass ratio of PVP and nano-graphene oxide powder is 1:5.5, obtain a uniformly dispersed colloidal solution through ultrasonic dispersion, and first place it in a water bath at 35°C , pH value of 7.8 under the condition of stirring reaction, and then stirring reaction in 28 ° C water bath, pH value of 7.0, the colloid obtained after the reaction was washed with deionized water and ethanol, dried to obtain the modified nano-oxidized Graphene powder.

In some embodiments of the present invention, the modified asphalt containing nanomaterials is prepared by mixing the matrix asphalt and the nano-graphene oxide at 120-140° C. and shearing and stirring at a speed of 2000-5000 r/min. become.

In the second aspect, the present invention protects an asphalt mixture, wherein the asphalt containing modified nano-graphene oxide described in the first aspect also contains a mineral mixture composed of coarse aggregate, fine aggregate and filler according to the gradation .

The coarse aggregate of the present invention can be selected crushed stone, crushed gravel, screened gravel, slag, etc. whose gradation and particle size meet the requirements; the fine aggregate can be selected from natural sand, artificial sand and Stone chips, etc.; the filler generally refers to mineral powder, etc., which play a role in filling and improving asphalt performance in the asphalt mixture, and strong basic rocks in limestone or magmatic rocks with gradation and particle size that meet the requirements can be used. Grind the mineral powder obtained.

The mineral mixture in the asphalt mixture of the present invention can be selected according to the actual requirements of asphalt pavement construction (such as climate conditions, traffic properties, construction conditions, etc.) with reference to national standards and methods disclosed in the prior art.

In the third aspect, the present invention protects the application of the asphalt containing modified nano-graphene oxide in the first aspect or the asphalt mixture in the second aspect in asphalt pavement construction.

Compared with the prior art, the asphalt containing modified nano-graphene oxide provided by the present invention adds a small amount of nano-graphene oxide prepared by a specific method to the conventional base asphalt, which can comprehensively improve the overall performance of the asphalt. For asphalt The temperature sensitivity, viscosity, plasticity and aging resistance of the product have been improved to varying degrees, making it more suitable for use in extreme environments.

Detailed ways

The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

Example 1

This embodiment provides a kind of asphalt containing modified nano-graphene oxide, the specific composition is: 100g of No. 70 matrix asphalt, 0.05g of modified nano-graphene oxide;

The modified nano-graphene oxide is prepared by the following method:

(1) Mix 0.15g of graphite with 34g of concentrated sulfuric acid and 3g of concentrated phosphoric acid, mechanically stir in an ice bath for 10 minutes, slowly add 0.9g of potassium permanganate, keep the temperature at 0°C, and stir for 2 hours in an ice bath , then stirred and reacted in a 40°C water bath for 60 minutes, then adjusted the temperature of the water bath to 95°C and stirred for 60 minutes;

(2) Suspend the reaction product obtained in step (1) in water, add 11g of hydrogen peroxide to react, the reaction product is repeatedly washed and centrifuged 5 times with an aqueous solution of pH5.5, and graphite oxide is peeled off during the washing process to form nano-graphene oxide Gel, dried at 60°C to obtain nanometer graphene oxide powder;

(3) Add the nano-graphene oxide powder obtained in step (2) to the PVP aqueous solution, wherein the mass ratio of PVP and nano-graphene oxide powder is 1:5.5, obtain a uniformly dispersed colloidal solution through ultrasonic dispersion, and first place it in a water bath at 35°C , pH value of 7.8 under the condition of stirring reaction, and then stirring reaction in 28 ° C water bath, pH value of 7.0, the colloid obtained after the reaction was washed with deionized water and ethanol, dried to obtain the modified nano-oxidized Graphene powder.

Example 2

This example provides a pitch containing modified nano-graphene oxide. Compared with Example 1, the only difference is that the amount of modified nano-graphene oxide is 0.03g.

Example 3

This example provides a pitch containing modified nano-graphene oxide. Compared with Example 1, the only difference is that the amount of modified nano-graphene oxide is 0.06g.

Example 4

This embodiment provides a pitch containing modified nano-graphene oxide. Compared with Example 1, the only difference is that in the process of preparing modified nano-graphene oxide, the stirring reaction in step (3) is only at 30 ° C. Water bath, pH 7.5 conditions.

Comparative example 1

This comparative example provides a kind of pitch containing modified nano-graphene oxide. Compared with Example 1, the difference is only: in the process of preparing modified nano-graphene oxide, polyvinylpyrrolidone and modified nano-graphene in step (3) The mass ratio of graphene oxide powder is 1:4.

Comparative example 2

This comparative example provides a kind of pitch containing modified nano-graphene oxide, compared with embodiment 1, the difference is only: the polyvinylpyrrolidone (PVP) that adopts when preparing modified nano-graphene oxide is replaced by hexadecyl Trimethylammonium bromide (CTAB).

Comparative example 3

This comparative example provides a kind of pitch containing modified nano-graphene oxide, compared with embodiment 1, the difference is only: the polyvinylpyrrolidone (PVP) that adopts when preparing modified nano-graphene oxide is replaced by N, N two Methylamide (DMF).

Experimental example

According to the relevant provisions of "Highway Engineering Asphalt and Asphalt Mixture Test Regulations" (JTJE20-2011), the asphalt containing modified nano-graphene oxide obtained in the various embodiments of the present invention and comparative examples was subjected to softening point, ductility, and penetration. Degree and penetration ratio test. in:

The softening point is the temperature at which asphalt changes from a solid state to a viscous fluid state, which reflects the temperature sensitivity of asphalt, and is specifically detected by the ring and ball method.

Penetration reflects the ability of asphalt to resist deformation under external force or self-weight. The smaller the penetration, the more viscous the bitumen.

Ductility reflects the nature of asphalt that deforms without damage when the external force is applied, and maintains the deformed shape after the external force is removed, and also reflects its self-healing performance. Specifically, the sample is made into an 8-shaped standard test mold (the minimum cross-sectional area in the middle is 1 cm ² ), and the length when it is broken at a tensile speed of 5 cm/min and a temperature of 10°C is the ductility. The greater the ductility, the stronger the plasticity of the asphalt.

The penetration ratio after evaporation reflects the degree of asphalt resistance to aging and stabilizes performance, specifically refers to the percentage of the ratio of the penetration of the asphalt after evaporation to the penetration before evaporation. The larger the penetration ratio after evaporation, the better the atmospheric stability of the asphalt and the slower the aging.

The test results are shown in Table 1.

Table 1: Performance Test Results

From the above results, it can be seen that parameters such as the softening point, penetration, and ductility of the asphalt containing modified nano-graphene oxide provided by the present invention all meet the relevant technical requirements of "Technical Specifications for Construction of Highway Asphalt Pavement" (JTGF40-2004). Among them, the comprehensive effect of the asphalt provided by Example 1 is the best.

Although, the present invention has been described in detail with general description, specific implementation and test above, but on the basis of the present invention, some modifications or improvements can be made to it, which will be obvious to those skilled in the art . Therefore, the modifications or improvements made on the basis of not departing from the spirit of the present invention all belong to the protection scope of the present invention.

Claims (10)

1. The asphalt containing modified nano graphene oxide is characterized by comprising matrix asphalt and modified nano graphene oxide accounting for 0.03 to 0.06 percent of the mass of the matrix asphalt;

the modified nano graphene oxide is prepared by the following steps:

(1) Mixing and stirring graphite, concentrated sulfuric acid and concentrated phosphoric acid, slowly adding potassium permanganate, and stirring for reaction;

(2) Adding deionized water into the reaction liquid obtained in the step (1), adding a hydrogen peroxide solution for reaction, repeatedly washing and centrifuging the obtained reaction product to strip graphite oxide and form nano graphene oxide gel, and drying to obtain nano graphene oxide powder;

(3) Mixing a polyvinylpyrrolidone aqueous solution with the nano graphene oxide powder, wherein the mass ratio of the polyvinylpyrrolidone to the nano graphene oxide powder is 1: (5 to 6), uniformly dispersing by ultrasonic, stirring for reaction, washing, drying,

the stirring reaction in the step (3) is performed under the conditions of temperature of 32 to 38 ℃ and pH value of 7.6 to 8, and then under the conditions of temperature of 25 to 30 ℃ and pH value of 6.8 to 7.2.

2. The asphalt containing the modified nano graphene oxide according to claim 1, wherein the mass of the modified nano graphene oxide accounts for 0.04 to 0.05 percent of the mass of the matrix asphalt.

3. The asphalt containing modified nano graphene oxide according to claim 1, wherein the base asphalt is No. 70 base asphalt.

4. The asphalt containing the modified nano graphene oxide according to claim 1, wherein the stirring reaction in the step (1) is performed in an ice bath, a water bath at 30 to 50 ℃ and a water bath at 80 to 95 ℃ in this order.

5. The asphalt containing the modified nano graphene oxide according to claim 1, wherein the repeated washing in the step (2) is performed by using an acidic aqueous solution.

6. The asphalt containing modified nano graphene oxide according to claim 5, wherein the acidic aqueous solution is an aqueous solution with a pH value of 5.3 to 5.7.

7. The asphalt containing the modified nano graphene oxide according to claim 1, wherein the modified nano graphene oxide powder is prepared by a method comprising the following steps:

(1) Mixing 0.15 part of graphite, 34 parts of concentrated sulfuric acid and 3 parts of concentrated phosphoric acid, mechanically stirring for 10 minutes in an ice bath, slowly adding 0.9 part of potassium permanganate, keeping the temperature at 0 ℃, stirring and reacting for 2 hours in the ice bath, then stirring and reacting for 60 minutes in a water bath at 40 ℃, and then adjusting the temperature of the water bath to 95 ℃, stirring and reacting for 60 minutes;

(2) Suspending the reaction product obtained in the step (1) in water, adding 11 parts of hydrogen peroxide for reaction, repeatedly washing and centrifuging the reaction product for 5 times by using a water solution with the pH of 5.5, stripping graphite oxide in the washing process to form nano graphene oxide gel, and drying at 60 ℃ to obtain nano graphene oxide powder;

(3) Adding the nano graphene oxide powder obtained in the step (2) into a PVP aqueous solution, wherein the mass ratio of PVP to the nano graphene oxide powder is 1:5.5, obtaining a uniformly dispersed colloidal solution through ultrasonic dispersion, firstly carrying out stirring reaction under the conditions of 35 ℃ water bath and pH value of 7.8, then carrying out stirring reaction under the conditions of 28 ℃ water bath and pH value of 7.0, washing colloid obtained after the reaction is finished with deionized water and ethanol, and drying to obtain the modified nano graphene oxide powder.

8. The asphalt containing modified nano graphene oxide according to any one of claims 1 to 7, wherein the asphalt is prepared by shearing, stirring and mixing the matrix asphalt and the nano graphene oxide at a temperature of 120 to 140 ℃ and at a speed of 2000 to 5000 r/min.

9. An asphalt mixture, which is characterized by comprising the asphalt containing the modified nano graphene oxide according to any one of claims 1 to 8, and a mineral mixture which comprises coarse aggregate, fine aggregate and filler and is composed according to a gradation.

10. The asphalt containing the modified nano graphene oxide according to any one of claims 1 to 8 or the asphalt mixture according to claim 9 for use in asphalt pavement construction.