A composite modified asphalt mixture for anti-skid surface layer of special road section and preparation method thereof

Abstract

The present invention relates to a special road section anti-skid surface composite modified asphalt mixture and a preparation method thereof, wherein the asphalt mixture is composed of filler, matrix asphalt, red mud, high modulus additive, a first active component, a second active component and aggregate, wherein the first active component is composed of o-cresol epoxy resin, polyphenol oxide resin and sepiolite; the second active component is composed of terpene resin, polyether ketone, glass fiber and carbon fiber. The special road section anti-skid surface composite modified asphalt mixture provided by the present invention can greatly improve the high temperature deformation resistance and low temperature crack resistance of the asphalt pavement, while enabling the pavement to have excellent anti-skid and overall durability. It can be applied to the asphalt surface paving of special road sections such as sharp turns, S-shaped routes, long longitudinal slopes, tunnel entrances and exits, and flat intersections. At the same time, the addition of red mud can also promote the utilization of solid waste, which is beneficial to saving resources and protecting the environment.

Description

Technical Field

[0001] The invention relates to the technical field of engineering materials for road traffic, and in particular to a composite modified asphalt mixture for an anti-skid surface layer of a special road section and a preparation method thereof. Background Art

[0002] Asphalt concrete is a typical viscoelastic material, and its performance is significantly affected by temperature and load, and its strength and modulus are relatively low. Asphalt pavements in some special sections, such as sharp turns, S-shaped routes, long longitudinal slopes, tunnel entrances and exits, flat intersections, interchanges, and service area entrances and exits, are very prone to waves, bumps, rutting, and shear-slip damage under driving. The reason is that the frequent turning, starting, acceleration, and braking of vehicles on the above special sections will cause large horizontal shear stresses on the top and inside of the asphalt surface layer. Long-term high-temperature shear and fatigue stress accelerate the speed of pavement damage, and the permanent deformation produced greatly affects driving safety. On the other hand, when turning, starting, accelerating, and braking on these special sections, vehicles need greater friction to provide horizontal force, which puts higher requirements on the anti-skid performance of the pavement, and also increases the wear degree of tires and pavement, accelerating the attenuation of the anti-skid performance of the pavement. In rainy areas, special sections such as zero slopes are prone to water accumulation, which is easy to cause water mist and water drift, thereby greatly reducing the adhesion between tires and pavement, and significantly reducing anti-skid performance. It is a dangerous section where traffic accidents frequently occur.

[0003] At present, there are few options for asphalt mixtures for special road sections in my country, and there is a lack of the optimal asphalt mixture that can adapt to long-term high-temperature shear and fatigue stress. Therefore, it is urgent to carry out design research on asphalt mixtures for special road sections to comprehensively improve driving safety. Summary of the invention

[0004] In view of the deficiencies in the prior art, the object of the present invention is to provide a composite modified asphalt mixture with excellent comprehensive performance and a preparation method thereof that can be used for anti-skid surface layers of special road sections.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A composite modified asphalt mixture for anti-skid surface layer of special road section, wherein the composite modified asphalt mixture comprises, by weight percentage: filler: 6% to 8%, base asphalt: 3% to 5%, red mud: 1.5% to 1.8%, high modulus additive: 0.20% to 0.25%, first active component: 0.12% to 0.13%, second active component: 0.13% to 0.15%, and the balance is aggregate;

[0007] The first active component is characterized by improving the high temperature stability of the road surface of a special road section, and the first active component is composed of the following components in parts by weight: 30-35 parts of o-cresol epoxy resin, 5-7 parts of polyphenol oxide resin, and 12-15 parts of sepiolite;

[0008] The second active component is characterized by improving the anti-skid and low-temperature crack resistance of the road surface of special road sections. The second active component is composed of the following components in parts by weight: 20-25 parts of terpene resin, 18-22 parts of polyether ketone, and 4-6 parts of glass fiber.

[0009] Further, a composite modified asphalt mixture for anti-skid surface layer of special road section, the composite modified asphalt mixture comprises, by weight percentage: filler: 6.5% to 8%, base asphalt: 3.5% to 5%, red mud: 1.6% to 1.8%, high modulus additive: 0.22% to 0.25%, first active component: 0.125% to 0.13%, second active component: 0.14% to 0.15%, and the balance is aggregate;

[0010] The first active component is characterized by improving the high temperature stability of the road surface of a special road section, and the first active component is composed of the following components in parts by weight: 32-35 parts of o-cresol epoxy resin, 6-7 parts of polyphenol oxide resin, and 13-15 parts of sepiolite;

[0011] The second active component is characterized by improving the anti-skid and low-temperature crack resistance of the road surface of special road sections. The second active component is composed of the following components in parts by weight: 22 to 25 parts of terpene resin, 19 to 22 parts of polyether ketone, and 4 to 6 parts of glass fiber.

[0012] Furthermore, the filler is composed of limestone powder and fly ash silicate cement, and the content of the fly ash silicate cement is 15-18wt%.

[0013] Furthermore, the aggregate is one or more of granite, limestone, diabase and basalt.

[0014] Furthermore, the base asphalt is No. 70 asphalt or No. 90 asphalt.

[0015] Furthermore, the sepiolite in the first active component is modified, and the modification method of the sepiolite is as follows: 1) primary modification: soaking the sepiolite in a nitric acid solution with a concentration of 0.5 to 0.8 mol / L and then drying it to obtain a primary modified sepiolite; 2) secondary modification: soaking the primary modified sepiolite in a nitric acid solution with a concentration of 3.0 to 3.5 mol / L and then drying it to obtain a secondary modified sepiolite; 3) tertiary modification: soaking the secondary modified sepiolite in a nitric acid solution with a concentration of 4.5 to 5.0 mol / L and then drying it to obtain a tertiary modified sepiolite.

[0016] Furthermore, 3 to 5 parts by weight of carbon fiber are added to the second active component.

[0017] The present invention also provides a method for preparing a composite modified asphalt mixture for an anti-skid surface layer of a special road section, comprising the following steps:

[0018] (1) Weighing raw materials: Weigh the components constituting the composite asphalt mixture according to the proportion; put the filler and aggregate into a homogenizing and mixing device, mix them evenly, heat them to 185-190° C., and keep the temperature constant;

[0019] (2) preheating the red mud to 220-230° C., then placing the heated red mud into the homogenizing and stirring equipment of step (1), heating and stirring, and gradually raising the temperature to 190-195° C., stirring at a constant temperature for 2-5 minutes; then adding a high modulus additive and a base asphalt and stirring at a constant temperature for 180-250 seconds to obtain a primary modified asphalt mixture;

[0020] (3) cooling the primary modified asphalt mixture by 5°C to 8°C, adding the first active component, and stirring at a constant temperature for 40 to 50 seconds to obtain a secondary modified asphalt mixture;

[0021] (4) adding a second active component to the second modified asphalt mixture, stirring at a constant temperature for 30 to 35 seconds, and pressing and molding to obtain a third modified asphalt mixture;

[0022] (5) Gradient insulation: 1) The thrice-modified asphalt mixture is kept at 160°C to 165°C for 30 minutes; 2) The thrice-modified asphalt mixture is kept at 120°C to 125°C for 10 to 12 minutes; 3) The thrice-modified asphalt mixture is finally kept at 175°C to 180°C for 40 to 45 minutes to obtain the composite modified asphalt mixture.

[0023] Furthermore, in the step (2), the red mud is preheated to 225-230°C, and then the heated red mud is placed in the reactor of step (1), heated and stirred, and the temperature is gradually increased to 192°C-195°C, and stirred at a constant temperature for 3-5 minutes; then the high modulus additive and the base asphalt are added and stirred at a constant temperature for 190-250 seconds to obtain a primary modified asphalt mixture.

[0024] Furthermore, in the step (5), the gradient insulation is performed as follows: 1) the thrice-modified asphalt mixture is kept at 162°C to 165°C for 30 minutes; 2) the thrice-modified asphalt mixture is kept at 122°C to 125°C for 11 to 12 minutes; 3) the thrice-modified asphalt mixture is finally kept at 177°C to 180°C for 42 to 45 minutes, thereby obtaining the composite modified asphalt mixture.

[0025] In a special road section anti-skid surface composite modified asphalt mixture and its preparation method provided by the present invention, in addition to adding commonly used fillers, matrix asphalt, high modulus additives, aggregates and other raw materials, the idea of ​​adding red mud to the composite asphalt mixture is proposed. Red mud is the polluting waste residue discharged when the aluminum industry extracts alumina, and has the characteristics of high pH value, high calcium, high silicon and low iron. Components such as calcite and siderite in red mud can act as a skeleton and have a certain cementing effect, while components such as goethite, gibbsite, opal, water glass, etc. have a certain cementing ability and also play a filling role. Therefore, red mud interacts with lightweight aggregates, can assist the dispersion of lightweight aggregates, and prevent lightweight aggregates from floating up, thereby improving the high-temperature deformation resistance and anti-skid ability of the composite asphalt mixture. Special road sections such as sharp turns, S-shaped routes, long and long longitudinal slopes, tunnel entrance and exit sections, etc., place higher requirements on the high temperature stability and anti-skid performance of pavement materials. For this purpose, the first active component and the second active component are added to further improve the high temperature stability, low temperature crack resistance and anti-skid performance of the composite asphalt mixture.

[0026] In the composite modified asphalt mixture for anti-skid surface layer of special road sections proposed by the present invention and the preparation method thereof, components such as o-cresol epoxy resin, polyphenol oxide resin and sepiolite in the first active component are dispersed in the composite asphalt mixture, and are mainly wrapped on the outer surface of the aggregate, forming a bridging effect between the aggregate and the matrix asphalt, and between the aggregates, generating a large bonding force, improving the viscoelastic properties and high-temperature deformation resistance of the composite asphalt mixture, and playing a role in further improving the high-temperature stability of the pavement of special road sections; the polyether ketone in the second active component has strong chemical resistance and wear resistance. Under the reinforcement of glass fiber, the polyether ketone and glass fiber form a stable composite reinforced material, which can effectively improve the anti-skid and low-temperature crack resistance of the pavement of special road sections.

[0027] In the composite modified asphalt mixture for anti-skid surface layer of special road sections proposed by the present invention and the preparation method thereof, sepiolite is modified to improve its water absorption and heat dissipation capacity, which helps to further improve the high-temperature stability of the road surface of special road sections; gradient insulation is performed when preparing the composite asphalt mixture, which can effectively reduce the floating of lightweight aggregates, and the distribution uniformity of aggregates and asphalt in the mixture is higher, which can improve the high-temperature stability, anti-skid performance and anti-rutting performance of the composite asphalt mixture; carbon fiber is also added to the second active component, and under the dual reinforcement effect of glass fiber and carbon fiber, polyether ketone, carbon fiber and glass fiber form a more stable composite reinforcement material, which can further improve the anti-skid performance and low-temperature crack resistance of the road surface of special road sections. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a product picture of red mud in the present invention;

[0029] Figure 2 (a)-(c) are product pictures of o-cresol epoxy resin, polyphenol oxide resin and sepiolite in the first active component of the present invention respectively;

[0030] Figure 2 (d)-(g) are product pictures of terpene resin, polyether ketone, glass fiber and carbon fiber in the second active component of the present invention respectively;

[0031] Figure 3 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0032] The following embodiments may help those skilled in the art to more fully understand the present invention, but shall not limit the present invention in any way.

[0033] The present invention discloses a composite modified asphalt mixture for anti-skid surface layer of special road section and a preparation method thereof. In a specific embodiment, the aggregate used includes coarse aggregate and fine aggregate, and the specific proportion of the coarse aggregate and the fine aggregate is proportioned according to specific requirements; the coarse aggregate should be processed by crushed stone with hard material and wear resistance, and should have a lower crushing value, abrasion value and a higher polishing value; the fine aggregate should be machine-made sand, and the particle size specifications are S14 (3mm-5mm) and S16 (0mm-3mm).

[0034] Example 1: Preparation of composite modified asphalt mixture for anti-skid surface layer of special road section

[0035] A composite modified asphalt mixture for anti-skid surface layer of special road sections, the asphalt mixture comprises, by weight percentage: filler: 6%, base asphalt: 3%, red mud: 1.5%, high modulus additive: 0.20%, first active component: 0.12%, second active component: 0.13%, and the balance is aggregate; the filler is composed of limestone powder and fly ash silicate cement, and the content of fly ash silicate cement is 15wt%; the aggregate is granite; the base asphalt is No. 70 asphalt;

[0036] The first active component is characterized by improving the high-temperature stability of the road surface of a special road section, and is composed of the following components in parts by weight: 30 parts of o-cresol epoxy resin, 5 parts of polyphenol epoxy resin, and 12 parts of sepiolite; the sepiolite in the first active component is modified before use, and the modification method of the sepiolite is as follows: 1) primary modification: the sepiolite is placed in a nitric acid solution with a concentration of 0.5 mol / L, soaked at 45°C for 40 minutes, taken out, washed with tap water, and dried to obtain a primary modified sepiolite; 2) secondary modification: the primary modified sepiolite is placed in a nitric acid solution with a concentration of 3.0 mol / L, soaked at 60°C for 30 minutes, taken out, washed with tap water, and dried to obtain a secondary modified sepiolite; 3) tertiary modification: the secondary modified sepiolite is placed in a nitric acid solution with a concentration of 4.5 mol / L, soaked at 68°C for 70 minutes, taken out, washed with tap water, and dried, and dried at 70°C;

[0037] The second active component is characterized by improving the anti-skid performance of the road surface of special road sections, and is composed of the following components in parts by weight: 20 parts of terpene resin, 18 parts of polyether ketone, 4 parts of glass fiber, and 3 parts of carbon fiber.

[0038] A method for preparing a composite modified asphalt mixture for an anti-skid surface layer of a special road section comprises the following steps:

[0039] (1) Weighing raw materials: Weigh the components constituting the composite asphalt mixture according to the proportion; put the filler and aggregate into a homogenizing and mixing device, mix them evenly, heat them to 185° C., and keep the temperature constant;

[0040] (2) preheating the red mud to 220° C., then placing the heated red mud into the homogenizing and stirring equipment of step (1), heating and stirring, and gradually raising the temperature to 190° C., and stirring at a constant temperature for 2 minutes; then adding a high modulus additive and a base asphalt, stirring at a constant temperature for 180 seconds, and obtaining a primary modified asphalt mixture;

[0041] (3) cooling the primary modified asphalt mixture by 5° C., adding the first active component, and stirring at a constant temperature for 40 seconds to obtain a secondary modified asphalt mixture;

[0042] (4) adding a second active component to the second modified asphalt mixture, stirring at a constant temperature for 30 seconds, and pressing and molding to obtain a third modified asphalt mixture;

[0043] (5) Gradient insulation: 1) The thrice-modified asphalt mixture is kept at 160°C for 30 minutes; 2) The thrice-modified asphalt mixture is kept at 120°C for 10 minutes; 3) The thrice-modified asphalt mixture is kept at 175°C for 40 minutes to obtain the composite modified asphalt mixture.

[0044] Example 2: Preparation of composite modified asphalt mixture for anti-skid surface layer of special road section

[0045] A composite modified asphalt mixture for anti-skid surface layer of special road sections, the asphalt mixture comprises, by weight percentage: filler: 8%, base asphalt: 5%, red mud: 1.8%, high modulus additive: 0.25%, first active component: 0.13%, second active component: 0.15%, and the balance is aggregate; the filler is composed of limestone powder and fly ash silicate cement, and the content of fly ash silicate cement is 18wt%; the aggregate is limestone; the base asphalt is No. 90 asphalt;

[0046] The first active component is characterized by improving the high-temperature stability of the road surface of a special road section, and is composed of the following components in parts by weight: 35 parts of o-cresol epoxy resin, 7 parts of polyphenol epoxy resin, and 15 parts of sepiolite; the sepiolite in the first active component is modified before use, and the modification method of the sepiolite is as follows: 1) primary modification: the sepiolite is placed in a nitric acid solution with a concentration of 0.8 mol / L, soaked at 50°C for 60 minutes, taken out, washed with tap water, and dried to obtain a primary modified sepiolite; 2) secondary modification: the primary modified sepiolite is placed in a nitric acid solution with a concentration of 3.5 mol / L, soaked at 65°C for 35 minutes, taken out, washed with tap water, and dried to obtain a secondary modified sepiolite; 3) tertiary modification: the secondary modified sepiolite is placed in a nitric acid solution with a concentration of 5.0 mol / L, soaked at 72°C for 75 minutes, taken out, washed with tap water, and dried, and dried at 75°C;

[0047] The second active component is characterized by improving the anti-skid performance of the road surface of special road sections, and is composed of the following components in parts by weight: 25 parts of terpene resin, 22 parts of polyether ketone, 6 parts of glass fiber, and 5 parts of carbon fiber.

[0048] A method for preparing a composite modified asphalt mixture for an anti-skid surface layer of a special road section comprises the following steps:

[0049] (1) Weighing raw materials: Weigh the components constituting the composite asphalt mixture according to the proportion; put the filler and aggregate into a homogenizing and mixing device, mix them evenly, heat them to 190° C., and keep the temperature constant;

[0050] (2) preheating the red mud to 230° C., then placing the heated red mud into the homogenizing and stirring equipment of step (1), heating and stirring, and gradually raising the temperature to 195° C., and stirring at a constant temperature for 5 minutes; then adding a high modulus additive and a base asphalt, stirring at a constant temperature for 250 seconds, and obtaining a primary modified asphalt mixture;

[0051] (3) cooling the primary modified asphalt mixture by 8° C., adding the first active component, and stirring at a constant temperature for 50 seconds to obtain a secondary modified asphalt mixture;

[0052] (4) adding a second active component to the second modified asphalt mixture, stirring at a constant temperature for 35 seconds, and pressing and molding to obtain a third modified asphalt mixture;

[0053] (5) Gradient insulation: 1) The thrice-modified asphalt mixture is kept at 165°C for 30 minutes; 2) The thrice-modified asphalt mixture is kept at 125°C for 12 minutes; 3) The thrice-modified asphalt mixture is kept at 180°C for 45 minutes to obtain the composite modified asphalt mixture.

[0054] Example 3: Preparation of composite modified asphalt mixture for anti-skid surface layer of special road section

[0055] A composite modified asphalt mixture for anti-skid surface layer of special road sections, the asphalt mixture comprises, by weight percentage: filler: 6.5%, base asphalt: 3.5%, red mud: 1.6%, high modulus additive: 0.22%, first active component: 0.125%, second active component: 0.14%, and the balance is aggregate; the filler is composed of limestone powder and fly ash silicate cement, and the content of fly ash silicate cement is 16wt%; the aggregate is diabase; the base asphalt is No. 90 asphalt;

[0056] The first active component is characterized by improving the high-temperature stability of the road surface of a special road section, and is composed of the following components in parts by weight: 32 parts of o-cresol epoxy resin, 6 parts of polyphenol epoxy resin, and 13 parts of sepiolite; the sepiolite in the first active component is modified before use, and the modification method of the sepiolite is as follows: 1) primary modification: the sepiolite is placed in a nitric acid solution with a concentration of 0.6 mol / L, soaked at 47°C for 50 minutes, taken out, washed with tap water, and dried to obtain a primary modified sepiolite; 2) secondary modification: the primary modified sepiolite is placed in a nitric acid solution with a concentration of 3.2 mol / L, soaked at 62°C for 33 minutes, taken out, washed with tap water, and dried to obtain a secondary modified sepiolite; 3) tertiary modification: the secondary modified sepiolite is placed in a nitric acid solution with a concentration of 4.7 mol / L, soaked at 69°C for 72 minutes, taken out, washed with tap water, and dried, and dried at 72°C;

[0057] The second active component is characterized by improving the anti-skid performance of the road surface of special road sections, and is composed of the following components in parts by weight: 22 parts of terpene resin, 19 parts of polyether ketone, 4 parts of glass fiber, and 4 parts of carbon fiber.

[0058] A method for preparing a composite modified asphalt mixture for an anti-skid surface layer of a special road section comprises the following steps:

[0059] (1) Weighing raw materials: Weighing the components constituting the composite asphalt mixture according to the proportion; putting the filler and aggregate into a homogenizing and mixing device, mixing them evenly and heating them to 187° C., and maintaining a constant temperature;

[0060] (2) preheating the red mud to 225° C., then placing the heated red mud into the homogenizing and stirring equipment of step (1), heating and stirring, and gradually raising the temperature to 192° C., and stirring at a constant temperature for 3 minutes; then adding a high modulus additive and a base asphalt, stirring at a constant temperature for 190 seconds, and obtaining a primary modified asphalt mixture;

[0061] (3) cooling the primary modified asphalt mixture by 6° C., adding the first active component, and stirring at a constant temperature for 45 seconds to obtain a secondary modified asphalt mixture;

[0062] (4) adding a second active component to the second-modified asphalt mixture, stirring at a constant temperature for 32 seconds, and pressing and molding to obtain a third-modified asphalt mixture;

[0063] (5) Gradient insulation: 1) The thrice-modified asphalt mixture is kept at 162°C for 30 minutes; 2) The thrice-modified asphalt mixture is kept at 122°C for 11 minutes; 3) The thrice-modified asphalt mixture is finally kept at 177°C for 42 minutes to obtain the composite modified asphalt mixture.

[0064] Example 4: Preparation of a composite modified asphalt mixture for anti-skid surface layer of special road sections. Compared with Example 3, in Example 4, the sepiolite in the first active component is not modified.

[0065] Example 5: Preparation of anti-skid surface composite modified asphalt mixture for special road sections. Compared with Example 3, step (5) of Example 5 does not perform gradient insulation, but only performs insulation at 177°C.

[0066] Comparative Example 1: Preparation of a composite modified asphalt mixture for an anti-skid surface layer of a special road section. Compared with Example 3, no red mud was added during the preparation of Comparative Example 1.

[0067] Comparative Example 2: Preparation of a composite modified asphalt mixture for an anti-skid surface layer of a special road section. Compared with Example 3, no first active component was added during the preparation of Comparative Example 2.

[0068] Comparative Example 3: Preparation of a composite modified asphalt mixture for an anti-skid surface layer of a special road section. Compared with Example 3, no second active component was added during the preparation of Comparative Example 3.

[0069] Blank experimental group: Compared with Example 3, the blank control group was not added with red mud and active components, and no gradient insulation was performed, but was only kept warm at 177°C.

[0070] The performance test results of Examples 1-5, Comparative Examples 1-3 and the blank control group are shown in Table 1 below;

[0071] Table 1

[0072]

[0073]

[0074] It can be seen from the above table that: (1) Compared with the test results of the blank control group, the various indicators of the anti-skid surface composite modified asphalt mixture for special road sections provided by this patent have been greatly improved, indicating that its various road performance has been significantly improved. (2) After adding red mud and the first active component, the dynamic stability of the composite modified asphalt mixture is significantly improved, indicating that both components can effectively improve the high-temperature performance of the asphalt mixture. (3) The addition of carbon fiber, glass fiber and polyether ketone significantly improves the structural depth and bending failure strain of the asphalt mixture, indicating that the second active component can further improve the anti-skid performance and low-temperature crack resistance of the composite asphalt mixture. (7) The asphalt mixture modified by sepiolite has higher dynamic stability, indicating that this method is conducive to further improving the high-temperature performance of the asphalt mixture. (8) Gradient insulation during the preparation of the composite asphalt mixture can effectively reduce the floating of lightweight aggregates, and the aggregates and asphalt are more evenly distributed in the mixture, thereby improving the high-temperature stability and anti-skid performance of the composite asphalt mixture.

[0075] Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements may be made thereto based on the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. A composite modified asphalt mixture for anti-skid surface layer of special road sections, characterized by: The composite modified asphalt mixture comprises, by weight percentage: filler: 6% to 8%, matrix asphalt: 3% to 5%, red mud: 1.5% to 1.8%, high modulus additive: 0.20% to 0.25%, first active component: 0.12% to 0.13%, second active component: 0.13% to 0.15%, and the balance is aggregate; The first active component is characterized by improving the high temperature stability of the road surface of a special road section, and the first active component is composed of the following components in parts by weight: 30-35 parts of o-cresol epoxy resin, 5-7 parts of polyphenol oxide resin, and 12-15 parts of sepiolite; The second active component is characterized by improving the anti-skid and low-temperature crack resistance of the road surface of special road sections. The second active component is composed of the following components in parts by weight: 20-25 parts of terpene resin, 18-22 parts of polyether ketone, and 4-6 parts of glass fiber.

2. The anti-skid surface composite modified asphalt mixture for special road sections according to claim 1, characterized in that: The composite modified asphalt mixture is measured by weight percentage, It includes: filler: 6.5% to 8%, matrix asphalt: 3.5% to 5%, red mud: 1.6% to 1.8%, high modulus additive: 0.22% to 0.25%, first active component: 0.125% to 0.13%, second active component: 0.14% to 0.15%, and the balance is aggregate; The first active component is characterized by improving the high temperature stability of the road surface of a special road section, and the first active component is composed of the following components in parts by weight: 32-35 parts of o-cresol epoxy resin, 6-7 parts of polyphenol oxide resin, and 13-15 parts of sepiolite; The second active component is characterized by improving the anti-skid and low-temperature crack resistance of the road surface of special road sections. The second active component is composed of the following components in parts by weight: 22 to 25 parts of terpene resin, 19 to 22 parts of polyether ketone, and 4 to 6 parts of glass fiber.

3. The anti-skid surface composite modified asphalt mixture for special road sections according to claim 1, characterized in that: The filler consists of limestone powder and fly ash silicate cement, and the content of the fly ash silicate cement is 15-18wt%.

4. The anti-skid surface composite modified asphalt mixture for special road sections according to claim 1, characterized in that: The aggregate is one or more of granite, limestone, diabase and basalt.

5. The anti-skid surface composite modified asphalt mixture for special road sections according to claim 1, characterized in that: The matrix asphalt is No. 70 asphalt or No. 90 asphalt.

6. The anti-skid surface composite modified asphalt mixture for special road sections according to claim 1, characterized in that: The sepiolite in the first active component is modified, and the modification method of the sepiolite is as follows: 1) primary modification: soaking the sepiolite in a nitric acid solution with a concentration of 0.5 to 0.8 mol / L and then drying it to obtain a primary modified sepiolite; 2) secondary modification: soaking the primary modified sepiolite in a nitric acid solution with a concentration of 3.0 to 3.5 mol / L and then drying it to obtain a secondary modified sepiolite; 3) tertiary modification: soaking the secondary modified sepiolite in a nitric acid solution with a concentration of 4.5 to 5.0 mol / L and then drying it to obtain a tertiary modified sepiolite.

7. The anti-skid surface composite modified asphalt mixture for special road sections according to claim 1, characterized in that: 3 to 5 parts by weight of carbon fiber are also added to the second active component.

8. The method for preparing a composite modified asphalt mixture for anti-skid surface layer of a special road section according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) Weighing raw materials: Weigh the components constituting the composite asphalt mixture according to the proportion; put the filler and aggregate into a homogenizing and mixing device, mix them evenly, and heat them to 185-190° C., and keep the temperature constant; (2) preheating the red mud to 220-230° C., then placing the heated red mud into the homogenizing and stirring equipment of step (1), heating and stirring, and gradually raising the temperature to 190-195° C., stirring at a constant temperature for 2-5 minutes; then adding a high modulus additive and a base asphalt and stirring at a constant temperature for 180-250 seconds to obtain a primary modified asphalt mixture; (3) cooling the primary modified asphalt mixture by 5°C to 8°C, adding the first active component, and stirring at a constant temperature for 40 to 50 seconds to obtain a secondary modified asphalt mixture; (4) adding a second active component to the second modified asphalt mixture, stirring at a constant temperature for 30 to 35 seconds, and pressing and molding to obtain a third modified asphalt mixture; (5) Gradient insulation: 1) The thrice-modified asphalt mixture is kept at 160°C to 165°C for 30 minutes; 2) The thrice-modified asphalt mixture is kept at 120°C to 125°C for 10 to 12 minutes; 3) The thrice-modified asphalt mixture is finally kept at 175°C to 180°C for 40 to 45 minutes to obtain the composite modified asphalt mixture.

9. The method for preparing a composite modified asphalt mixture for anti-skid surface layer of a special road section according to claim 8, characterized in that: In the step (2), the red mud is preheated to 225-230° C., and then the heated red mud is placed in the homogenizing and stirring equipment of the step (1). The homogenizing and stirring equipment of the step (1) is a reactor, which is heated and stirred, and the temperature is gradually raised to 192° C.-195° C., and stirred at a constant temperature for 3-5 minutes; then a high modulus additive and a base asphalt are added and stirred at a constant temperature for 190-250 seconds to obtain a primary modified asphalt mixture.

10. The method for preparing a composite modified asphalt mixture for anti-skid surface layer of a special road section according to claim 8, characterized in that: The gradient insulation in step (5) is as follows: 1) the thrice-modified asphalt mixture is kept at 162°C to 165°C for 30 minutes; 2) the thrice-modified asphalt mixture is kept at 122°C to 125°C for 11 to 12 minutes; 3) the thrice-modified asphalt mixture is finally kept at 177°C to 180°C for 42 to 45 minutes to obtain the composite modified asphalt mixture.

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