A kind of multifunctional modified emulsified asphalt and preparation method thereof

Abstract

The invention provides a multifunctional modified emulsified asphalt and a preparation method thereof, which belongs to the technical field of asphalt, and comprises the following components by weight: 400-450 parts of hard asphalt, 150-200 parts of soft asphalt, 100-120 parts of modified styrene-butadiene latex, 50-60 parts of modified filler, 20-25 parts of emulsifier, 10-15 parts of stabilizer, 8-12 parts of defoamer, pH value regulator and 350-400 parts of water. The multifunctional modified emulsified asphalt prepared by the invention can improve the low-temperature and high-temperature properties of the emulsified asphalt at the same time, and has excellent aging resistance and high stability, and can be used for synchronous paving of ultra-thin wear layer technology for bridge deck paving.

Description

Technical Field

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

[0002] Emulsified asphalt is a liquid product formed by dispersing viscous asphalt in water containing an emulsifier through emulsification technology. Traditionally used road asphalt must be melted at high temperatures before use, while emulsified asphalt can be used at room temperature, which greatly simplifies the construction process and reduces energy consumption and environmental pollution. Emulsified asphalt shows its unique advantages in the repair and maintenance of asphalt pavements. The technology of synchronous paving of ultra-thin wearing layers has significant economic benefits and social value in the maintenance of bridge deck pavement. However, this synchronous construction process places more stringent requirements on the bonding materials between layers. Traditional emulsified asphalt or modified emulsified asphalt often fails to meet the performance standards required for synchronous paving of ultra-thin wearing layers.

[0003] When emulsified asphalt is used for simultaneous paving of ultra-thin wear layers for bridge deck maintenance, the following technical problems may be encountered: (1) The demulsification speed of emulsified asphalt needs to be moderate. Too fast demulsification may lead to poor asphalt film formation, while too slow demulsification will affect construction efficiency and interlayer bonding effect. (2) Traditional emulsified asphalt or modified emulsified asphalt is a spray type with a low solid content, resulting in a small film thickness and weak bonding strength of the bonding layer, making it difficult to meet the technical requirements of simultaneous paving of ultra-thin wear layers. (3) Due to the low solid content and improper combination of emulsifier types, the demulsification speed of traditional emulsified asphalt is slow, making it difficult to meet the technical requirements of simultaneous paving of fast demulsification. (4) The higher the solid content, the greater the difficulty of emulsification, and the storage stability is difficult to guarantee.

[0004] In the existing technology, emulsified asphalt is modified by using styrene butadiene latex. Although this method has shown remarkable performance in improving the low-temperature performance of asphalt, it is still insufficient in enhancing its high-temperature stability and is difficult to meet the application needs of different regions. In addition, the adhesion between emulsified asphalt modified by styrene butadiene latex and stone is relatively weak, which may lead to phenomena such as falling particles or rutting in actual applications.

[0005] Therefore, there is an urgent need for a multifunctional modified emulsified asphalt and a preparation method thereof. Summary of the invention

[0006] The purpose of the present invention is to provide a multifunctional modified emulsified asphalt and a preparation method thereof.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A multifunctional modified emulsified asphalt, comprising the following components in parts by weight: 400-450 parts of hard asphalt, 150-200 parts of soft asphalt, 100-120 parts of modified styrene-butadiene latex, 50-60 parts of modified filler, 20-25 parts of emulsifier, 10-15 parts of stabilizer, 8-12 parts of defoamer, pH value regulator and 350-400 parts of water;

[0009] The preparation method of the modified styrene butadiene latex comprises the following steps: under the condition of 1.0MPa-1.5MPa, 150-170 parts of deionized water, 2-4 parts of 1-allyloxy-3-(4-nonylphenol)-2-propanol polyoxyethylene (10) ether ammonium sulfate (Guangzhou Shanghe Chemical Technology Co., Ltd., model: DNS-86), 35-40 parts of butadiene, 60-65 parts of styrene, 2-4 parts of methacrylic acid, 2-4 parts of acrylonitrile, and 5-9 parts of silicone monomer are mixed, the temperature is raised to 50-80°C, 0.5-0.8 parts of ammonium persulfate are added, the reaction is carried out for 2-3h, 0.3-0.7 parts of n-dodecyl mercaptan are added, the reaction is carried out for 1-1.5h, and the temperature is cooled to room temperature to obtain the modified styrene butadiene latex.

[0010] Furthermore, the organosilicon monomer is a mixture of tetravinyltetramethylcyclotetrasilazane (Anhui Mingyi Silicon Industry Co., Ltd., CAS No.: 5162-63-0), vinyltriethoxysilane (CAS No.: 78-08-0) and allyltrimethoxysilane (CAS No.: 2551-83-9) in a weight ratio of (1.2-1.5): (0.2-0.4): 1.

[0011] The softening point of emulsified asphalt is an important physical index, which refers to the temperature at which the asphalt component in the emulsified asphalt begins to soften and flow under specified conditions. This index reflects the temperature sensitivity of asphalt, that is, as the temperature rises, the faster the asphalt softens. The higher the softening point, the stronger the ability of the asphalt to maintain its shape and not easily deform at high temperatures. In the prior art, emulsified asphalt is generally modified directly using styrene butadiene latex, and the softening point of the obtained emulsified asphalt is low. The present invention can improve the softening point of emulsified asphalt by modifying styrene butadiene latex. Analysis is that acrylonitrile and organosilicon monomers are introduced when preparing modified styrene butadiene latex. The introduction of acrylonitrile can increase the polarity of the polymer chain, thereby increasing the glass transition temperature of the material. The organosilicon monomer forms a three-dimensional network structure through cross-linking, which helps to improve the modulus and hardness of the material, thereby increasing the softening point.

[0012] Furthermore, the hard asphalt is a mixture of 70# heavy cross-linking asphalt, 90# heavy cross-linking asphalt and 110# heavy cross-linking asphalt in a weight ratio of (1.4-1.6):1:(0.2-0.4).

[0013] Furthermore, the soft asphalt is a mixture of 10# construction asphalt and 30# construction asphalt in a weight ratio of (1.3-1.5):1.

[0014] In the prior art, 70# heavy traffic asphalt is usually modified by styrene butadiene latex, but it is found that the needle penetration of the multifunctional modified emulsified asphalt prepared by modifying 70# heavy traffic asphalt with the modified styrene butadiene latex of the present invention is not ideal. The present invention can make the multifunctional modified emulsified asphalt maintain a suitable needle penetration by compounding a plurality of hard asphalts and soft asphalts at the same time, and at the same time make the multifunctional modified emulsified asphalt maintain a good ductility at low temperature. However, the ductility of the multifunctional modified emulsified asphalt after aging under this condition is not ideal.

[0015] Furthermore, the preparation method of the modified filler comprises the following steps:

[0016] (1) mixing kaolin, diatomaceous earth and carboxylated double-walled carbon nanotubes to obtain a mixed filler;

[0017] (2) Under a nitrogen atmosphere, 1 part by weight of 3-isocyanatepropyltrimethoxysilane and 0.12-0.15 parts by weight of a mixed filler are mixed, 40-45 parts by weight of N,N-dimethylformamide are added, the mixture is stirred at 100-105° C. for 2-3 hours, centrifuged, and freeze-dried to obtain a first modified filler;

[0018] (3) 10 parts by weight of the first modified filler and 70-75 parts by weight of ethanol are mixed, and then 10-15 parts by weight of a nano-titanium dioxide aqueous solution is added dropwise, stirred at 55-60° C. for 2-3 hours, centrifuged, and freeze-dried to obtain a modified filler.

[0019] Furthermore, the weight ratio of kaolin, diatomaceous earth and carboxylated double-walled carbon nanotubes is (1.5-1.7):1:(0.3-0.5).

[0020] Furthermore, the weight percentage of nano-titanium dioxide in the nano-titanium dioxide aqueous solution is 20-30%. The particle size of nano-titanium dioxide is 5-10nm, and the specific surface area is 20-30m 2 / g.

[0021] The present invention attempts to improve the stability of emulsified asphalt by adding fillers, but the dispersion effect of natural fillers in emulsified asphalt is not ideal. The present invention can improve the 1d stability of emulsified asphalt by modifying the filler. Analysis shows that the modified filler can improve the interfacial adhesion between asphalt, modified styrene-butadiene latex and water in the multifunctional modified emulsified asphalt, making the emulsified asphalt more uniform and stable. And when a specific ratio of fillers is compounded with a specific ratio of hard asphalt and soft asphalt, the ductility of the emulsified asphalt after aging can be improved.

[0022] In order to improve the stability of the multifunctional modified emulsified asphalt 5d, the emulsifier further comprises C8-C10 fatty alcohol polyoxyethylene ether, distearyl dimethyl ammonium chloride and hexadecyl trimethyl ammonium chloride in a weight ratio of 1: (1.2-1.4): (0.5-0.8).

[0023] Furthermore, the stabilizer is selected from one or more of methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, and hydroxypropyl methyl cellulose.

[0024] Furthermore, the defoaming agent is selected from one or more of TEGO 901W defoaming agent, TEGO 902W defoaming agent, and TEGO 801W defoaming agent.

[0025] Furthermore, the pH adjuster is one or more of acetic acid, hydrochloric acid or sulfuric acid.

[0026] The invention provides a method for preparing a multifunctional modified emulsified asphalt, comprising the following steps: adding an emulsifier into deionized water, adjusting the pH to 2-3 with a pH regulator, heating the water to 80-85°C, adding the water to a colloid mill, starting the colloid mill, slowly adding hard asphalt heated to 155-160°C into the colloid mill, adding soft asphalt heated to 145-150°C after the addition, adding the remaining components, stirring evenly, and obtaining the multifunctional modified emulsified asphalt.

[0027] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0028] 1. The present invention can improve the softening point of emulsified asphalt by modifying styrene butadiene latex; at the same time, the modified styrene butadiene latex can enable the emulsified asphalt to maintain a good ductility at low temperatures.

[0029] 2. The present invention selects hard asphalt and soft asphalt at the same time, and then modifies it by modified styrene-butadiene latex, so that the multifunctional modified emulsified asphalt can maintain a suitable penetration, and at the same time, the emulsified asphalt can maintain a good ductility at low temperature.

[0030] 3. The present invention can improve the 1d stability of emulsified asphalt by modifying the filler.

[0031] 4. When a specific ratio of filler is compounded with a specific ratio of hard asphalt and soft asphalt, the ductility of the emulsified asphalt after aging can be improved.

[0032] 5. The present invention can improve the stability of the multifunctional modified emulsified asphalt 5d by adding an emulsifier in a specific ratio. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] The raw materials used in the following examples of the present invention are all commercially available products:

[0035] 70# heavy traffic asphalt, 90# heavy traffic asphalt, and 110# heavy traffic asphalt were purchased from Hebei Dezhishan Petrochemical Co., Ltd.

[0036] 10# construction asphalt and 30# construction asphalt were purchased from Weifang Changxu Building Materials Co., Ltd. and produced by Qilu Petrochemical.

[0037] 1-Allyloxy-3-(4-nonylphenol)-2-propanol polyoxyethylene (10) ether ammonium sulfate was purchased from Guangzhou Shanghe Chemical Technology Co., Ltd., CAS No.: 184719-88-8.

[0038] Tetravinyltetramethylcyclotetrasilazane was purchased from Anhui Mingyi Silicon Industry Co., Ltd., CAS No.: 5162-63-0.

[0039] Kaolin, 325 mesh residue 0.5%, specific surface area 23m 2 / g. Purchased from Ningbo Jiahe New Material Technology Co., Ltd.

[0040] Diatomaceous earth, median mesh number 1000. Guangdong Senda Diatomaceous Earth Material Co., Ltd., model SD3004A#.

[0041] Carboxylated double-walled carbon nanotubes, 0.5-2 μm in length and 5-15 nm in diameter, were purchased from Jiangsu Xianfeng Nanomaterials Technology Co., Ltd.

[0042] Nano titanium dioxide, the particle size of nano titanium dioxide is 5-10nm, and the specific surface area is 20-30m 2 / g. Purchased from Beijing Dekedao Gold Technology Co., Ltd.

[0043] C8-C10 fatty alcohol polyoxyethylene ether was purchased from Hubei Chengfeng Chemical Co., Ltd., CAS No.: 111-09-3.

[0044] Distearyl dimethyl ammonium chloride was purchased from Shandong Wangtong Chemical Co., Ltd., CAS: 107-64-2.

[0045] Hexadecyltrimethylammonium chloride was purchased from Shandong Haochen New Material Technology Co., Ltd., CAS: 112-02-7. Example 1

[0046] The present embodiment provides a multifunctional modified emulsified asphalt, comprising the following components in parts by weight: 420 parts of hard asphalt, 170 parts of soft asphalt, 110 parts of modified styrene-butadiene latex, 55 parts of modified filler, 23 parts of emulsifier, 12 parts of stabilizer, 10 parts of defoamer, 380 parts of water and pH regulator.

[0047] The hard asphalt is a mixture of 70# heavy cross-linking asphalt, 90# heavy cross-linking asphalt and 110# heavy cross-linking asphalt in a weight ratio of 1.5:1:0.3.

[0048] The soft asphalt is a mixture of 10# construction asphalt and 30# construction asphalt in a weight ratio of 1.4:1.

[0049] The emulsifier comprises C8-C10 fatty alcohol polyoxyethylene ether, distearyl dimethyl ammonium chloride and hexadecyl trimethyl ammonium chloride in a weight ratio of 1:1.3:0.6.

[0050] The stabilizer is methylcellulose.

[0051] The defoamer is TEGO 901W defoamer.

[0052] The pH adjuster is acetic acid.

[0053] In terms of weight, the preparation method of the modified styrene butadiene latex comprises the following steps: under the condition of 1.2 MPa, 160 parts of deionized water, 3 parts of 1-allyloxy-3-(4-nonylphenol)-2-propanol polyoxyethylene (10) ether ammonium sulfate, 37 parts of butadiene, 62 parts of styrene, 3 parts of methacrylic acid, 3 parts of acrylonitrile, and 7 parts of silicone monomer are mixed, the temperature is raised to 60°C, 0.6 parts of ammonium persulfate are added, the reaction is carried out for 2.5 hours, 0.5 parts of n-dodecyl mercaptan are added, the reaction is carried out for 1.2 hours, and the temperature is cooled to room temperature to obtain the modified styrene butadiene latex.

[0054] The organic silicon monomer is a mixture of tetravinyltetramethylcyclotetrasilazane, vinyltriethoxysilane and allyltrimethoxysilane in a weight ratio of 1.3:0.3:1.

[0055] The preparation method of the modified filler comprises the following steps:

[0056] (1) mixing kaolin, diatomaceous earth and carboxylated double-walled carbon nanotubes in a weight ratio of 1.6:1:0.4 to obtain a mixed filler;

[0057] (2) Under a nitrogen atmosphere, 1 part by weight of 3-isocyanatepropyltrimethoxysilane and 0.14 parts by weight of a mixed filler were mixed, 42 parts by weight of N,N-dimethylformamide were added, the mixture was stirred at 102° C. for 2.6 h, centrifuged, and freeze-dried to obtain a first modified filler;

[0058] (3) 10 parts by weight of the first modified filler and 72 parts by weight of ethanol were mixed, and then 13 parts by weight of a nano-titanium dioxide aqueous solution was added dropwise, wherein the weight percentage of nano-titanium dioxide in the nano-titanium dioxide aqueous solution was 25%, and the mixture was stirred at 58° C. for 2.7 h, centrifuged, and freeze-dried to obtain a modified filler.

[0059] The preparation method of the multifunctional modified emulsified asphalt comprises the following steps: adding an emulsifier to deionized water, adjusting the pH to 2.5 with a pH regulator, heating to 82° C., adding the water to a colloid mill, starting the colloid mill, slowly adding heavy traffic asphalt heated to 157° C. to the colloid mill, adding soft asphalt heated to 148° C. after the addition is complete, adding the remaining components, stirring evenly, and obtaining the multifunctional modified emulsified asphalt. Example 2

[0060] The present embodiment provides a multifunctional modified emulsified asphalt, comprising the following components in parts by weight: 400 parts of hard asphalt, 200 parts of soft asphalt, 100 parts of modified styrene-butadiene latex, 60 parts of modified filler, 20 parts of emulsifier, 15 parts of stabilizer, 8 parts of defoamer, 400 parts of water and pH regulator.

[0061] The hard asphalt is a mixture of 70# heavy cross-linking asphalt, 90# heavy cross-linking asphalt and 110# heavy cross-linking asphalt in a weight ratio of 1.4:1:0.4.

[0062] The soft asphalt is a mixture of 10# construction asphalt and 30# construction asphalt in a weight ratio of 1.5:1.

[0063] The emulsifier comprises C8-C10 fatty alcohol polyoxyethylene ether, distearyl dimethyl ammonium chloride and hexadecyl trimethyl ammonium chloride in a weight ratio of 1:1.2:0.8.

[0064] The stabilizer is carboxymethyl cellulose.

[0065] The defoamer is TEGO 902W defoamer.

[0066] The pH adjuster is acetic acid.

[0067] The preparation method of the modified styrene butadiene latex comprises the following steps: under the condition of 1.5 MPa, 150 parts of deionized water, 4 parts of 1-allyloxy-3-(4-nonylphenol)-2-propanol polyoxyethylene (10) ether ammonium sulfate, 35 parts of butadiene, 65 parts of styrene, 2 parts of methacrylic acid, 4 parts of acrylonitrile and 5 parts of silicone monomer are mixed, the temperature is raised to 80°C, 0.5 parts of ammonium persulfate are added, the reaction is carried out for 3 hours, 0.3 parts of n-dodecyl mercaptan are added, the reaction is carried out for 1.5 hours, and the temperature is cooled to room temperature to obtain the modified styrene butadiene latex.

[0068] The organic silicon monomer is a mixture of tetravinyltetramethylcyclotetrasilazane, vinyltriethoxysilane and allyltrimethoxysilane in a weight ratio of 1.2:0.4:1.

[0069] The preparation method of the modified filler comprises the following steps:

[0070] (1) mixing kaolin, diatomaceous earth and carboxylated double-walled carbon nanotubes in a weight ratio of 1.5:1:0.5 to obtain a mixed filler;

[0071] (2) Under a nitrogen atmosphere, 1 part by weight of 3-isocyanatepropyltrimethoxysilane and 0.12 parts by weight of a mixed filler were mixed, 45 parts by weight of N,N-dimethylformamide were added, the mixture was stirred at 100° C. for 3 h, centrifuged, and freeze-dried to obtain a first modified filler;

[0072] (3) 10 parts by weight of the first modified filler and 75 parts by weight of ethanol were mixed, and then 10 parts by weight of a nano-titanium dioxide aqueous solution was added dropwise, wherein the weight percentage of nano-titanium dioxide in the nano-titanium dioxide aqueous solution was 30%, and the mixture was stirred at 55° C. for 3 h, centrifuged, and freeze-dried to obtain a modified filler.

[0073] The preparation method of the multifunctional modified emulsified asphalt comprises the following steps: adding an emulsifier to deionized water, adjusting the pH to 2 with a pH regulator, heating to 85° C., adding the water to a colloid mill, starting the colloid mill, slowly adding heavy traffic asphalt heated to 155° C. to the colloid mill, adding soft asphalt heated to 145° C. after the addition is complete, adding the remaining components, stirring evenly, and obtaining the multifunctional modified emulsified asphalt.

[0074] Comparative Example 1

[0075] The difference between this comparative example and Example 1 is that the preparation method of the modified styrene-butadiene latex is different, specifically, 3 parts of acrylonitrile and 7 parts of organosilicon monomer are replaced by 10 parts of organosilicon monomer.

[0076] Comparative Example 2

[0077] The difference between this comparative example and Example 1 is that the organic silicon monomer is a mixture of tetravinyltetramethylcyclotetrasilazane, vinyltriethoxysilane and allyltrimethoxysilane in a weight ratio of 1:1:1.

[0078] Comparative Example 3

[0079] The difference between this comparative example and Example 1 is that kaolin, diatomaceous earth and carboxylated double-walled carbon nanotubes are mixed in a weight ratio of 1:1:1.

[0080] Comparative Example 4

[0081] The difference between this comparative example and Example 1 is that the hard asphalt is a mixture of 70# heavy cross-linking asphalt, 90# heavy cross-linking asphalt and 110# heavy cross-linking asphalt in a weight ratio of 1:1:1.

[0082] Comparative Example 5

[0083] The difference between this comparative example and Example 1 is that the soft asphalt is a mixture of 10# construction asphalt and 30# construction asphalt in a weight ratio of 1:1.

[0084] Comparative Example 6

[0085] The difference between this comparative example and Example 1 is that 420 parts of hard asphalt and 170 parts of soft asphalt are replaced by 490 parts of hard asphalt and 100 parts of soft asphalt.

[0086] Comparative Example 7

[0087] The difference between this comparative example and Example 1 is that the emulsifier includes C8-C10 fatty alcohol polyoxyethylene ether, distearyl dimethyl ammonium chloride and cetyl trimethyl ammonium chloride in a weight ratio of 1:1:1.

[0088] Performance Testing

[0089] The performance tests were performed on the multifunctional modified emulsified asphalts prepared in Examples 1-2 and Comparative Examples 1-7.

[0090] The performance test was carried out with reference to the standard technical requirements in the Technical Specifications for Highway Asphalt Pavement Construction (JTGF40-2004). The 1d stability and 5d stability of the samples were tested according to the T0655 test method; the evaporation residue content index was tested according to the T0651 test method; the softening point index was tested according to the T0606 test method; the 5℃ elongation index was tested according to the T0605 test method; the needle penetration (100g, 25℃, 5s) index was tested according to the T0604 test method. According to the Test Procedures for Asphalt and Asphalt Mixtures for Highway Engineering (JTGE20-2011), 40g of asphalt was taken in a rotary thin film oven (RTFO) for 100min during aging, and the elongation retention rate after aging was determined = elongation after aging / elongation before aging*100%.

[0091] The test results are shown in Table 1:

[0092] Table 1 Performance test results

[0093]

[0094] It can be seen from the above performance test results that the multifunctional modified emulsified asphalts of Examples 1-2 have excellent comprehensive performance, especially the comprehensive performance of Example 1 is the most outstanding, which is mainly due to the synergistic effect of multiple components.

[0095] However, the comparative examples are significantly inferior to the embodiments in the corresponding performance tests because they do not adopt the necessary technical solutions. The preparation method of the modified styrene-butadiene latex in comparative example 1 is different, and the softening point and ductility of the multifunctional modified emulsified asphalt are both reduced; the ratio of the organosilicon monomer in comparative example 2 is different, which affects the cross-linking structure of the multifunctional modified emulsified asphalt, further causing the softening point of the multifunctional modified emulsified asphalt to decrease. The filler composition in comparative example 3 is different, and the stability of the multifunctional modified emulsified asphalt 1d decreases, while affecting the anti-aging performance of the multifunctional modified emulsified asphalt. The different ratios of hard asphalt in comparative example 4, the different ratios of soft asphalt in comparative example 5, and the different amounts of hard asphalt and soft asphalt added in comparative example 6 all affect the anti-aging performance of the multifunctional modified emulsified asphalt. The different ratios of emulsifiers in comparative example 7 affect the stability of the multifunctional modified emulsified asphalt 5d. The above experimental results further prove the importance of the technical solution defined in the present invention for its technical effect.

[0096] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A multifunctional modified emulsified asphalt, characterized in that: The invention comprises the following components in parts by weight: 400-450 parts of hard asphalt, 150-200 parts of soft asphalt, 100-120 parts of modified styrene-butadiene latex, 50-60 parts of modified filler, 20-25 parts of emulsifier, 10-15 parts of stabilizer, 8-12 parts of defoamer, 350-400 parts of water and pH value regulator; The preparation method of the modified styrene butadiene latex comprises the following steps: under the condition of 1.0MPa-1.5MPa, 150-170 parts of deionized water, 2-4 parts of 1-allyloxy-3-(4-nonylphenol)-2-propanol polyoxyethylene (10) ether ammonium sulfate, 35-40 parts of butadiene, 60-65 parts of styrene, 2-4 parts of methacrylic acid, 2-4 parts of acrylonitrile and 5-9 parts of silicone monomer are mixed, the temperature is raised to 50-80°C, 0.5-0.8 parts of ammonium persulfate are added, the reaction is carried out for 2-3h, 0.3-0.7 parts of n-dodecyl mercaptan are added, the reaction is carried out for 1-1.5h, and the temperature is cooled to room temperature to obtain the modified styrene butadiene latex; The organosilicon monomer is a mixture of tetravinyltetramethylcyclotetrasilazane, vinyltriethoxysilane and allyltrimethoxysilane in a weight ratio of (1.2-1.5):(0.2-0.4):1; The hard asphalt is a mixture of 70# heavy traffic asphalt, 90# heavy traffic asphalt and 110# heavy traffic asphalt in a weight ratio of (1.4-1.6):1:(0.2-0.4); The soft asphalt is a mixture of 10# construction asphalt and 30# construction asphalt in a weight ratio of (1.3-1.5):1; The preparation method of the modified filler comprises the following steps: (1) mixing kaolin, diatomaceous earth and carboxylated double-walled carbon nanotubes to obtain a mixed filler; (2) Under a nitrogen atmosphere, 1 part by weight of 3-isocyanatepropyltrimethoxysilane and 0.12-0.15 parts by weight of a mixed filler are mixed, 40-45 parts by weight of N,N-dimethylformamide are added, the mixture is stirred at 100-105° C. for 2-3 hours, centrifuged, and freeze-dried to obtain a first modified filler; (3) 10 parts by weight of the first modified filler and 70-75 parts by weight of ethanol are mixed, and then 10-15 parts by weight of a nano-titanium dioxide aqueous solution is added dropwise, stirred at 55-60° C. for 2-3 hours, centrifuged, and freeze-dried to obtain a modified filler; The weight ratio of kaolin, diatomaceous earth and carboxylated double-walled carbon nanotubes is (1.5-1.7):1:(0.3-0.5); The emulsifier comprises C8-C10 fatty alcohol polyoxyethylene ether, distearyl dimethyl ammonium chloride and hexadecyl trimethyl ammonium chloride in a weight ratio of 1: (1.2-1.4): (0.5-0.8).

2. The multifunctional modified emulsified asphalt according to claim 1, characterized in that: The weight percentage of nano-titanium dioxide in the nano-titanium dioxide aqueous solution is 20-30%, the particle size of nano-titanium dioxide is 5-10nm, and the specific surface area is 20-30m 2 / g.

3. The multifunctional modified emulsified asphalt according to claim 1, characterized in that: The stabilizer is selected from one or more of methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose and hydroxypropyl methyl cellulose.

4. A method for preparing the multifunctional modified emulsified asphalt according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: adding an emulsifier into deionized water, adjusting the pH to 2-3 with a pH regulator, heating the water to 80-85°C, adding the water into a colloid mill, starting the colloid mill, slowly adding hard asphalt heated to 155-160°C into the colloid mill, adding soft asphalt heated to 145-150°C, adding the remaining components, stirring evenly, and obtaining a multifunctional modified emulsified asphalt.

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