A kind of red mud asphalt mixture and preparation method thereof

Abstract

The present application relates to the field of asphalt materials, and specifically discloses a red mud asphalt mixture and a preparation method thereof. First, red mud, bisphenol A epoxy resin, and coupling agent solution are prepared in a weight ratio of (20-30): (6-10): (2-4) to obtain modified red mud, and then coarse aggregate, fine aggregate, asphalt, and modified red mud are prepared in a weight ratio of (60-80): (20-40): (8-10): (8-10) to obtain the red mud asphalt mixture. The modified red mud provided in the present application has good compatibility with asphalt, and the red mud asphalt mixture provided in the present application has good water resistance, high temperature deformation resistance, and low temperature crack resistance.

Description

Technical Field

[0001] The present application relates to the field of asphalt materials, and in particular to a red mud asphalt mixture and a preparation method thereof. Background Art

[0002] Red mud is the polluting waste discharged when the aluminum industry extracts alumina. Its main components are Fe2O3, Al2O3, CaO, SiO2, etc. Red mud is usually difficult to recycle and can only be stored. With the development of the aluminum industry and the reduction of bauxite ore grade, the amount of red mud stored will become larger and larger. Moreover, since red mud contains alkaline substances, the alkali in the red mud will be dissolved with the flushing of rainwater, which may pollute surface water and groundwater. Therefore, the comprehensive utilization of red mud is becoming an increasingly important research topic.

[0003] In the related art, a Chinese patent with publication number CN110317463B proposes a multi-particle-size red mud modified asphalt, a preparation method, and an asphalt mixture using the modified asphalt. The modified asphalt includes asphalt and red mud; the red mud is mixed in a ratio of large particle size: medium particle size: small particle size = (3-4): 2:2; the preparation method is to evenly mix three different particle sizes of red mud calcined at high temperature according to the above mass ratio, add asphalt and stir evenly to obtain multi-particle-size red mud modified asphalt; the red mud modified asphalt can be used in asphalt mixture. Compared with single-particle-size red mud modified asphalt, multi-particle-size red mud modified asphalt has excellent high, medium and low temperature performance without adding other additives and modifiers, and can be well used in asphalt pavement.

[0004] Since the main components of red mud are various metal oxides and have strong alkalinity, the adhesion between red mud and asphalt is not strong and the compatibility is poor, resulting in a large gap between red mud and asphalt; when asphalt is used to pave the road, rainwater can easily penetrate the gap between red mud and asphalt, making the asphalt's water resistance poor, thus affecting the service life of the asphalt pavement. Summary of the invention

[0005] In view of the problems existing in the prior art, the first object of the present application is to provide a modified red mud, which has good compatibility with asphalt, and the asphalt mixture prepared using the modified red mud has good water resistance.

[0006] The second purpose of the present application is to provide a red mud asphalt mixture, which uses modified red mud as raw material to realize the utilization of red mud. The prepared asphalt mixture has good water resistance, high-temperature deformation resistance and low-temperature crack resistance.

[0007] To achieve the above first purpose, this application provides the following technical solutions:

[0008] A modified red mud is prepared from red mud, bisphenol A epoxy resin and coupling agent solution in a weight ratio of (20-30): (6-10): (2-4).

[0009] By adopting the above technical scheme, the coupling agent modifies the surface of metal oxides such as Fe2O3, Al2O3 and non-metallic oxides such as SiO2 in red mud, thereby enhancing the hydrophobicity of the red mud, which helps to avoid agglomeration of particles in the red mud, thereby making the red mud evenly dispersed. At the same time, the enhanced hydrophobicity of the red mud also helps to improve the compatibility of the red mud with asphalt and bisphenol A epoxy resin; the bisphenol A epoxy resin is cross-linked in the asphalt to form a network structure, and the red mud particles are filled in the network structure, which improves the adhesion between the red mud and the asphalt, thereby improving the water resistance and mechanical properties of the red mud asphalt mixture.

[0010] Furthermore, the coupling agent solution comprises 10-20 parts by weight of a coupling agent and 70-80 parts by weight of an organic solvent, wherein the coupling agent is selected from one or more of a silane coupling agent, a titanate coupling agent, and an aluminate coupling agent, and the organic solvent is selected from one or more of ethanol, ethylene glycol, and acetone.

[0011] Furthermore, the step of preparing the modified red mud includes: mixing the coupling agent solution and the red mud, and then adding bisphenol A epoxy resin and mixing to obtain the modified red mud.

[0012] By adopting the above technical scheme, the coupling agent is first dissolved in an organic solvent to obtain a coupling agent solution, and then the coupling agent solution is added to red mud, which helps to evenly disperse the coupling agent in the red mud, thereby improving the efficiency of red mud modification; then bisphenol A epoxy resin is added to coat the surface of the red mud with the bisphenol A epoxy resin to obtain modified red mud. Since the bisphenol A epoxy resin is lipophilic, when the modified red mud is subsequently added to asphalt, the bisphenol A epoxy resin coated on the surface of the red mud acts as an lipophilic medium, which helps to evenly disperse the modified red mud in the asphalt, thereby further improving the compatibility of red mud and asphalt.

[0013] Furthermore, the coupling agent solution and red mud are mixed in the following manner: spraying the coupling agent solution on the red mud and stirring, wherein the stirring speed is 100-200 rpm and the stirring time is 40-60 min.

[0014] By adopting the above technical solution, the coupling agent solution and the red mud are mixed by a method of spraying and stirring at the same time, which helps to make the coupling agent solution and the red mud mixed evenly, thereby improving the efficiency of red mud modification.

[0015] To achieve the above second purpose, this application provides the following technical solutions:

[0016] A red mud asphalt mixture is prepared by mixing the following raw materials in parts by weight: 60-80 parts of coarse aggregate, 20-40 parts of fine aggregate, 8-10 parts of asphalt, and 8-10 parts of modified red mud; wherein the coarse aggregate is crushed stone, and the fine aggregate is natural sand.

[0017] Furthermore, the red mud asphalt mixture also includes 0.5-1 parts by weight of silicon dioxide.

[0018] Furthermore, the silicon dioxide is silicon dioxide modified by a silane coupling agent, and the average particle size of the silicon dioxide modified by a silane coupling agent is 20-500 nm.

[0019] By adopting the above technical solution, silica fills the gap between asphalt and red mud, thereby improving the water resistance and mechanical properties of the asphalt mixture; the silane coupling agent-modified silica has better compatibility with asphalt, thereby further improving the water resistance and mechanical properties of the asphalt mixture.

[0020] Furthermore, the red mud asphalt mixture also includes 0.5-1 parts by weight of alginate, and the alginate is selected from one or more of sodium alginate, potassium alginate, and calcium alginate.

[0021] By adopting the above technical solution, the viscosity of alginate makes the bond between red mud and asphalt tighter, thereby further improving the water resistance and mechanical properties of the asphalt mixture.

[0022] Furthermore, the red mud asphalt mixture also includes 6-8 parts by weight of mineral fiber.

[0023] By adopting the above technical solution, mineral fibers make asphalt, red mud and other components evenly dispersed in the red mud asphalt mixture, which helps to improve the water resistance and mechanical properties of the asphalt mixture.

[0024] The present application provides a method for preparing the above-mentioned red mud asphalt mixture, comprising the following steps:

[0025] S1. Heat and melt the asphalt;

[0026] S2. Preheating the coarse aggregate and the fine aggregate;

[0027] S3. Add silane coupling agent-modified silica and modified red mud to the melted asphalt obtained in step S1, and stir at 160-180°C for 5-10 minutes;

[0028] S4. Add the preheated coarse aggregate and fine aggregate to the mixture obtained in step S3, and stir at 160-180°C for 5-10 minutes; S5. Add alginate and mineral fiber to the mixture obtained in step S4, and stir at 160-180°C for 5-10 minutes.

[0029] By adopting the above technical scheme, modified red mud and silane coupling agent modified silica have good compatibility with asphalt, which helps to improve the water resistance of asphalt mixture. After asphalt is mixed with coarse aggregate and fine aggregate, alginate and mineral fiber are added to further improve the water resistance, high temperature deformation resistance and low temperature crack resistance of asphalt.

[0030] In summary, this application includes the following beneficial technical effects:

[0031] 1. The present application provides a modified red mud, which uses a coupling agent and a bisphenol A epoxy resin in a specific ratio to modify the red mud, thereby improving the compatibility of the red mud and asphalt, thereby improving the water resistance of the red mud asphalt mixture;

[0032] 2. The present application improves a red mud asphalt mixture, realizes the utilization of red mud, and obtains a red mud asphalt mixture with good performance. The red mud asphalt mixture is further improved in terms of water resistance, high temperature deformation resistance, and low temperature crack resistance by using a silane coupling agent modified silica with a specific particle size, as well as alginate and mineral fiber.

[0033] 3. The red mud asphalt mixture obtained in this application has good water resistance, and the water immersion residual stability reaches more than 90%;

[0034] 4. The red mud asphalt mixture obtained in this application has good high-temperature deformation resistance, with a Marshall stability of more than 12kN and a dynamic stability of more than 1700 times / mm;

[0035] 5. The red mud asphalt mixture obtained in the present application has good low-temperature crack resistance, with a low-temperature splitting strength ratio of more than 90% and a maximum bending tensile strain of more than 2500με. DETAILED DESCRIPTION

[0036] The present application is further described in detail below in conjunction with examples. The following examples are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention. In the following examples, if specific conditions are not specified, they are carried out according to normal conditions or conditions recommended by the manufacturer. The methods used are conventional methods known in the art unless otherwise specified, and the consumables and reagents used are commercially available unless otherwise specified. Unless otherwise specified, the professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. In addition, any method or material similar or equivalent to the recorded content may also be applied to the present invention.

[0037] Example 1

[0038] The preparation method of the red mud asphalt mixture provided in Example 1 is as follows:

[0039] 1) Crush the Bayer red mud and grind it until there is no lumps or agglomerates on the surface.

[0040] 2) Mix KH-560 silane coupling agent and ethanol in a weight ratio of 15:75 to obtain a coupling agent solution.

[0041] 3) Take 25 parts by weight of the red mud obtained in step 1) and 3 parts by weight of the coupling agent solution obtained in step 2), spray the coupling agent solution on the red mud, stir at a stirring speed of 150 rpm for 50 min, then add 8 parts by weight of bisphenol A epoxy resin, and continue stirring for 20 min to obtain modified red mud.

[0042] 4) Heat and melt the 70# base asphalt.

[0043] 5) Preheat the crushed stone and natural sand to 160℃.

[0044] 6) Take 9 parts by weight of the melted asphalt obtained in step 4), add 9 parts by weight of the modified red mud obtained in step 3), and stir at 160-180° C. for 8 minutes.

[0045] 7) Add 60 parts by weight of preheated crushed stone and 40 parts by weight of preheated natural sand to the mixture obtained in step 6), and stir at 160-180° C. for 8 min to obtain a red mud asphalt mixture.

[0046] Example 2

[0047] The preparation method of the red mud asphalt mixture provided in Example 2 is as follows:

[0048] 1) Crush the Bayer red mud and grind it until there is no lumps or agglomerates on the surface.

[0049] 2) Mix KH-560 silane coupling agent and ethanol in a weight ratio of 15:75 to obtain a coupling agent solution.

[0050] 3) Take 25 parts by weight of the red mud obtained in step 1) and 3 parts by weight of the coupling agent solution obtained in step 2), spray the coupling agent solution on the red mud, stir at a stirring speed of 150 rpm for 50 min, then add 8 parts by weight of bisphenol A epoxy resin, and continue stirring for 20 min to obtain modified red mud.

[0051] 4) Heat and melt the 70# base asphalt.

[0052] 5) Preheat the crushed stone and natural sand to 160℃.

[0053] 6) Take 9 parts by weight of the melted asphalt obtained in step 4), add 9 parts by weight of the modified red mud obtained in step 3), and stir at 160-180° C. for 8 minutes.

[0054] 7) Add 70 parts by weight of preheated crushed stone and 30 parts by weight of preheated natural sand to the mixture obtained in step 6), and stir at 160-180° C. for 8 min to obtain a red mud asphalt mixture.

[0055] Example 3

[0056] The preparation method of the red mud asphalt mixture provided in Example 3 is as follows:

[0057] 1) Crush the Bayer red mud and grind it until there is no lumps or agglomerates on the surface.

[0058] 2) Mix KH-560 silane coupling agent and ethanol in a weight ratio of 15:75 to obtain a coupling agent solution.

[0059] 3) Take 25 parts by weight of the red mud obtained in step 1) and 3 parts by weight of the coupling agent solution obtained in step 2), spray the coupling agent solution on the red mud, stir at a stirring speed of 150 rpm for 50 min, then add 8 parts by weight of bisphenol A epoxy resin, and continue stirring for 20 min to obtain modified red mud.

[0060] 4) Heat and melt the 70# base asphalt.

[0061] 5) Preheat the crushed stone and natural sand to 160℃.

[0062] 6) Take 9 parts by weight of the melted asphalt obtained in step 4), add 9 parts by weight of the modified red mud obtained in step 3), and stir at 160-180° C. for 8 minutes.

[0063] 7) Add 80 parts by weight of preheated crushed stone and 20 parts by weight of preheated natural sand to the mixture obtained in step 6), and stir at 170° C. for 8 minutes to obtain a red mud asphalt mixture.

[0064] Example 4

[0065] Example 4 provides a red mud asphalt mixture. The preparation method of the red mud asphalt mixture refers to Example 2. The only difference between Example 4 and Example 2 is that in step 6), the weight part of asphalt is 8 parts by weight and the weight part of modified red mud is 10 parts by weight.

[0066] Example 5

[0067] Example 5 provides a red mud asphalt mixture. The preparation method of the red mud asphalt mixture refers to Example 2. The only difference between Example 5 and Example 2 is that in step 6), the weight part of asphalt is 10 weight parts, and the weight part of modified red mud is 8 weight parts.

[0068] Example 6

[0069] Example 6 provides a red mud asphalt mixture. The preparation method of the red mud asphalt mixture refers to Example 2. The only difference between Example 6 and Example 2 is that in step 3), the weight part of red mud is 20 weight parts, the weight part of coupling agent solution is 4 weight parts, and the weight part of bisphenol A epoxy resin is 6 weight parts.

[0070] Example 7

[0071] Example 7 provides a red mud asphalt mixture. The preparation method of the red mud asphalt mixture refers to Example 2. The only difference between Example 7 and Example 2 is that in step 3), the weight part of red mud is 30 weight parts, the weight part of coupling agent solution is 2 weight parts, and the weight part of bisphenol A epoxy resin is 10 weight parts.

[0072] Example 8

[0073] Example 8 provides a red mud asphalt mixture. The preparation method of the red mud asphalt mixture refers to Example 2. The only difference between Example 8 and Example 2 is that in step 2), the weight ratio of KH-560 silane coupling agent and ethanol is 10:80.

[0074] Example 9

[0075] Example 9 provides a red mud asphalt mixture. The preparation method of the red mud asphalt mixture refers to Example 2. The only difference between Example 9 and Example 2 is that in step 2), the weight ratio of KH-560 silane coupling agent and ethanol is 20:70.

[0076] Example 10

[0077] Example 10 provides a red mud asphalt mixture. The preparation method of the red mud asphalt mixture refers to Example 2. The only difference between Example 10 and Example 2 is that in step 6), 0.5 parts by weight of silicon dioxide is further added, and the average particle size of the silicon dioxide is 200 nm.

[0078] Embodiment 11

[0079] Example 11 provides a red mud asphalt mixture. The preparation method of the red mud asphalt mixture refers to Example 10. The only difference between Example 11 and Example 10 is that in step 6), the weight part of silicon dioxide is 0.8 weight part.

[0080] Example 12

[0081] Example 12 provides a red mud asphalt mixture. The preparation method of the red mud asphalt mixture refers to Example 10. The only difference between Example 12 and Example 10 is that in step 6), the weight part of silicon dioxide is 1 weight part.

[0082] Embodiment 13

[0083] Example 13 provides a red mud asphalt mixture. The preparation method of the red mud asphalt mixture refers to Example 11. The only difference between Example 13 and Example 11 is that in step 6), silicon dioxide is replaced by silicon dioxide modified by a silane coupling agent.

[0084] Embodiment 14

[0085] Example 14 provides a red mud asphalt mixture. The preparation method of the red mud asphalt mixture refers to Example 13. The only difference between Example 14 and Example 13 is that in step 6), the average particle size of the silane coupling agent modified silica is 20 nm.

[0086] Embodiment 15

[0087] Example 15 provides a red mud asphalt mixture. The preparation method of the red mud asphalt mixture refers to Example 13. The only difference between Example 15 and Example 13 is that in step 6), the average particle size of the silane coupling agent modified silica is 500 nm.

[0088] Example 16

[0089] Example 16 provides a red mud asphalt mixture. The preparation method of the red mud asphalt mixture refers to Example 13. The only difference between Example 16 and Example 13 is that it also includes step 8): adding 0.8 parts by weight of calcium alginate to the mixture obtained in step 7).

[0090] Embodiment 17

[0091] Example 17 provides a red mud asphalt mixture. The preparation method of the red mud asphalt mixture refers to Example 16. The only difference between Example 17 and Example 16 is that in step 8), 7 parts by weight of mineral fiber are further added.

[0092] Comparative Example 1

[0093] The preparation method of the asphalt mixture provided in Comparative Example 1 is as follows:

[0094] 1) Heat and melt the 70# base asphalt.

[0095] 2) Preheat the crushed stone and natural sand to 160℃.

[0096] 3) Take 9 parts by weight of the melted asphalt obtained in step 1), add 70 parts by weight of preheated crushed stone and 30 parts by weight of preheated natural sand, and stir at 160-180° C. for 8 minutes to obtain an asphalt mixture.

[0097] Comparative Example 2

[0098] The preparation method of the red mud asphalt mixture provided in Comparative Example 2 is as follows:

[0099] 1) Crush the Bayer red mud and grind it until there is no lumps or agglomerates on the surface.

[0100] 2) Heat and melt the 70# base asphalt.

[0101] 3) Preheat the crushed stone and natural sand to 160℃.

[0102] 4) Take 9 parts by weight of the melted asphalt obtained in step 2), add 9 parts by weight of the red mud obtained in step 1), and stir at 160-180° C. for 8 minutes.

[0103] 5) Add 70 parts by weight of preheated crushed stone and 30 parts by weight of preheated natural sand to the mixture obtained in step 4), and stir at 160-180° C. for 8 min to obtain a red mud asphalt mixture.

[0104] Comparative Example 3

[0105] The preparation method of the red mud asphalt mixture provided in Comparative Example 3 is as follows:

[0106] 1) Crush the Bayer red mud and grind it until there is no lumps or agglomerates on the surface.

[0107] 2) Mix KH-560 silane coupling agent and ethanol in a weight ratio of 15:75 to obtain a coupling agent solution.

[0108] 3) Heat and melt the 70# base asphalt.

[0109] 4) Preheat the crushed stone and natural sand to 160℃.

[0110] 5) 6.25 parts by weight of the red mud obtained in step 1), 0.75 parts by weight of the coupling agent solution obtained in step 2), 2 parts by weight of bisphenol A epoxy resin, and 9 parts by weight of the melted asphalt obtained in step 3) were mixed and stirred at 160-180° C. for 8 min.

[0111] 6) Add 70 parts by weight of preheated crushed stone and 30 parts by weight of preheated natural sand to the mixture obtained in step 5), and stir at 160-180° C. for 8 min to obtain a red mud asphalt mixture.

[0112] Performance Testing

[0113] For the red mud asphalt mixtures provided in Examples 1 to 17 and Comparative Examples 1 to 3 of the present application, the following performance tests were performed in accordance with JTG E20-2011 "Test Procedures for Asphalt and Asphalt Mixtures for Highway Engineering":

[0114] The Marshall stability and water residual stability of red mud asphalt mixture were tested according to T0709-2011 “Marshall stability test for asphalt mixture”.

[0115] The dynamic stability of red mud asphalt mixture is tested according to T0719-2011 "Asphalt mixture rutting test".

[0116] The low-temperature splitting strength ratio of red mud asphalt mixture is tested according to T0729-2000 "Freeze-thaw splitting test of asphalt mixture".

[0117] The maximum bending strain is tested according to T0715-2011 "Asphalt Mixture Bending Test".

[0118] The test results are shown in Table 1.

[0119] Table 1 Marshall stability, water immersion residual stability, dynamic stability, low temperature splitting strength ratio, maximum bending strain test results of Examples 1-17 and Comparative Examples 1-3

[0120]

[0121] The present application is described in detail below in conjunction with the experimental data provided in Table 1.

[0122] Examples 1-3 investigated the effect of the amount of coarse aggregate and fine aggregate added on the performance of red mud asphalt mixture. The results showed that when the weight ratio of coarse aggregate to fine aggregate was 7:3, the performance of the red mud asphalt mixture was better in all aspects.

[0123] Taking Example 2 as a control, Examples 4-5 investigated the effects of the addition amounts of asphalt and modified red mud on the performance of red mud asphalt mixtures. The results showed that when the weight ratio of asphalt to modified red mud was 1:1, the performance of the red mud asphalt mixture was better in all aspects.

[0124] Taking Example 2 as a control, Examples 6-7 investigated the effect of the weight ratio of red mud, bisphenol A epoxy resin, and coupling agent solution in modified red mud on the performance of red mud asphalt mixture. The results showed that when the weight ratio of red mud, bisphenol A epoxy resin, and coupling agent solution in modified red mud was 25:8:3, the performance of the red mud asphalt mixture was better in all aspects.

[0125] Taking Example 2 as a control, Examples 8-9 investigated the effect of the weight ratio of the coupling agent and the chemical solvent in the coupling agent solution on the performance of the red mud asphalt mixture. The results showed that when the weight ratio of the coupling agent and the chemical solvent in the coupling agent solution was 15:75, the performance of the red mud asphalt mixture was better in all aspects.

[0126] Examples 10-12 added silica on the basis of Example 2, and investigated the effect of the amount of silica added on the performance of red mud asphalt mixture. The results showed that after adding silica, various performances of the red mud asphalt mixture were improved. This is because silica can fill the gap between asphalt and red mud. Comprehensively comparing various performances of the red mud asphalt mixture, Example 11 is relatively superior.

[0127] Taking Example 11 as a control, Example 13 replaced silica with silane coupling agent modified silica. The results showed that compared with silica, silane coupling agent modified silica has better compatibility with asphalt, thereby effectively filling the gap between asphalt and red mud, and further enhancing the water resistance, high temperature deformation resistance and low temperature crack resistance of the red mud asphalt mixture.

[0128] Taking Example 13 as a control, Examples 14-15 investigated the effect of the particle size of silane coupling agent modified silica on the performance of red mud asphalt mixture. The results showed that silane coupling agent modified silica with an average particle size of 200 nm can effectively fill the gap between asphalt and red mud, making the performance improvement of red mud asphalt mixture more obvious.

[0129] Example 16 adds alginate on the basis of Example 13. The results show that the viscosity of alginate makes the bonding between red mud and asphalt tighter. After adding alginate, the water resistance, high-temperature deformation resistance and low-temperature crack resistance of the red mud asphalt mixture are improved.

[0130] Example 17 adds mineral fiber on the basis of Example 16. The results show that the high-temperature deformation resistance of the red mud asphalt mixture with the addition of mineral fiber is significantly improved, and the water resistance and low-temperature crack resistance are also improved. This is because mineral fiber helps to evenly disperse asphalt, red mud and other components in the red mud asphalt mixture.

[0131] Compared with Example 2, the overall performance of the asphalt mixture of Example 1 is reduced, indicating that after adding modified red mud, the water resistance, high-temperature deformation resistance and low-temperature crack resistance of the asphalt mixture are improved relative to ordinary asphalt mixture. The present application realizes the utilization of red mud and achieves an effect superior to that of ordinary asphalt mixture.

[0132] Compared with Example 2, the overall performance of the red mud asphalt mixture of Comparative Example 2 is reduced, indicating that the unmodified red mud has poor compatibility with asphalt, which is not conducive to improving the water resistance, high-temperature deformation resistance and low-temperature crack resistance of the asphalt mixture.

[0133] Compared with Example 2, the overall performance of the red mud asphalt mixture of Comparative Example 3 is reduced, indicating that when asphalt, red mud, bisphenol A type epoxy resin, and coupling agent solution are mixed in one pot, the compatibility of the components is poor, resulting in poor water resistance, high-temperature deformation resistance, and low-temperature crack resistance of the asphalt mixture; Example 2 first mixes the red mud with the coupling agent solution, then adds bisphenol A type epoxy resin to obtain modified red mud, and then adds the modified red mud to the asphalt, which can make the components fully compatible, thereby obtaining a red mud asphalt mixture with better performance.

[0134] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A red mud asphalt mixture, characterized in that: The invention is prepared by mixing the following raw materials in parts by weight: 60-80 parts of coarse aggregate, 20-40 parts of fine aggregate, 8-10 parts of asphalt, 8-10 parts of modified red mud, 0.5-1 part of alginate, and 6-8 parts of mineral fiber; wherein the coarse aggregate is crushed stone, and the fine aggregate is natural sand; The modified red mud is prepared from red mud, bisphenol A epoxy resin, and coupling agent solution in a weight ratio of (20-30): (6-10): (2-4); The alginate is selected from one or more of sodium alginate, potassium alginate and calcium alginate; The preparation method of the modified red mud comprises the following steps: mixing the coupling agent solution and the red mud, adding bisphenol A epoxy resin, and mixing to obtain the modified red mud.

2. The red mud asphalt mixture according to claim 1, characterized in that: The coupling agent solution comprises 10-20 parts by weight of a coupling agent and 70-80 parts by weight of an organic solvent, wherein the coupling agent is selected from one or more of a silane coupling agent, a titanate coupling agent, and an aluminate coupling agent, and the organic solvent is selected from one or more of ethanol, ethylene glycol, and acetone.

3. The red mud asphalt mixture according to claim 1, characterized in that: The coupling agent solution and red mud are mixed in the following manner: spraying the coupling agent solution on the red mud and stirring, wherein the stirring speed is 100-200 rpm and the stirring time is 40-60 min.

4. The red mud asphalt mixture according to claim 1, characterized in that: The red mud asphalt mixture also includes 0.5-1 parts by weight of silicon dioxide.

5. The red mud asphalt mixture according to claim 4, characterized in that: The silicon dioxide is silicon dioxide modified by a silane coupling agent, and the average particle size of the silicon dioxide modified by a silane coupling agent is 20-500 nm.

6. A method for preparing the red mud asphalt mixture according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Heat and melt the asphalt; S2. Preheating the coarse aggregate and the fine aggregate; S3. Add silane coupling agent-modified silica and modified red mud to the melted asphalt obtained in step S1, and stir at 160-180°C for 5-10 minutes; S4. Add the preheated coarse aggregate and fine aggregate to the mixture obtained in step S3 and stir at 160-180°C for 5-10min; S5. Add alginate and mineral fiber to the mixture obtained in step S4, and stir at 160-180° C. for 5-10 minutes.

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