Composite modified asphalt based on coal liquefied asphalt and rubber powder and preparation method of composite modified asphalt

Abstract

The invention relates to the technical field of asphalt materials, and particularly discloses composite modified asphalt based on coal liquefied asphalt and rubber powder and a preparation method of the composite modified asphalt. The preparation method comprises the following steps: heating the matrix asphalt to 170-180 DEG C, adding the coal liquefaction asphalt and the solubilizer, and stirring to obtain a first asphalt mixed system; keeping 170-180 DEG C, adding the pretreated rubber powder and a plasticizer into the first asphalt mixed system, mixing, stirring, and shearing at a high speed to obtain a second asphalt mixed system; slowly adding a stabilizer into the second asphalt mixed system at 180-185 DEG C, mixing, and shearing at a high speed at 170-180 DEG C to obtain composite modified asphalt; the composite modified asphalt comprises the following raw materials in parts by mass: 350-450 parts of matrix asphalt, 80-120 parts of coal liquefaction asphalt, 110-130 parts of pretreated rubber powder, 8-12 parts of a solubilizer, 15-30 parts of a plasticizer and 1-3 parts of a stabilizer.

Description

Technical Field

[0001] The invention relates to the technical field of asphalt materials, and specifically discloses a composite modified asphalt based on coal liquefaction asphalt and rubber powder and a preparation method thereof. Background Art

[0002] In recent years, with the continuous development of industry, waste rubber and coal liquefaction asphalt and other wastes have increased, causing environmental pollution. From the perspective of resource recycling and environmental protection, it is very necessary to transform and utilize waste rubber and coal liquefaction asphalt with high added value. The application of waste tires and coal liquefaction asphalt in road construction can not only consume a large amount of these solid wastes and solve the problem of environmental pollution, but also help improve the road performance of asphalt pavement and save construction costs.

[0003] CN101863637B discloses a road asphalt concrete admixture, which is prepared by adding an appropriate amount of plasticizer, rubber powder, coupling agent and dispersant to the coal direct liquefaction residue and mixing at high speed for 10 minutes at 140-165°C, and then replacing 10-40% of conventional matrix asphalt with the admixture for the preparation of asphalt concrete. The admixture prepared by this method has complex ingredients, a large amount of residue added, and a low mixing temperature, which makes it difficult for the liquefied residue to be evenly mixed with the rubber powder, and easily causes segregation and phase separation problems in the admixture.

[0004] CN201610703007.9 discloses a coal liquefaction residue composite asphalt and a preparation method thereof, wherein the coal liquefaction residue is mixed with base asphalt, a plasticizer and waste rubber powder to prepare the composite asphalt, which can replace the base asphalt as a road paving material. However, the performance of the composite asphalt is general, and the untreated waste rubber powder has shown obvious disadvantages and defects in actual use in road engineering.

[0005] In summary, a composite modified asphalt based on coal liquefaction asphalt and rubber powder with excellent performance is provided, which can meet the paving requirements of road projects, improve the utilization rate of coal liquefaction asphalt and waste tire rubber powder in road projects, solve the problems of asphalt resource shortage and environmental pollution, and reduce the production cost of composite modified asphalt, which is of great significance. Summary of the invention

[0006] The object of the present invention is to provide a composite modified asphalt based on coal liquefaction asphalt and rubber powder and a preparation method thereof, so as to solve the problems raised in the prior art.

[0007] To achieve the above object, the present invention provides the following technical solution: a method for preparing a composite modified asphalt based on coal liquefaction asphalt and rubber powder, comprising the following steps:

[0008] Step 1: heat the base asphalt to 170-180°C, add coal liquefied asphalt and solubilizer, and stir to obtain a first asphalt mixing system;

[0009] Step 2: heat the first asphalt mixture system at 180° C., add the pretreated rubber powder and the plasticizer, mix, stir, and high-speed shear to obtain a second asphalt mixture system;

[0010] Step 3: slowly add the stabilizer to the second asphalt mixture system at 180-185°C and mix; high-speed shear at 170-180°C to obtain a composite modified asphalt;

[0011] More optimally, the stirring time in step one is 10~40min, and the stirring rate is 1000~4000r / min; the stirring time in step two is 10~40min, and the stirring rate is 1000~4000r / min; the high-speed shearing time in step two is 5~30min, and the shearing rate is 2000~8000r / min; the high-speed shearing time in step three is 5~30min, and the shearing rate is 2000~6000r / min.

[0012] More optimally, the stirring time in step one is 20~30min, and the stirring rate is 2000~3000r / min; the stirring time in step two is 20~30min, and the stirring rate is 2000~3000r / min; the high-speed shearing time in step two is 10~20min, and the shearing rate is 4000~7000r / min; the high-speed shearing time in step three is 8~20min, and the shearing rate is 3000~5000r / min.

[0013] More optimally, the composite modified asphalt includes the following raw materials, calculated by weight: 350-450 parts of base asphalt, 80-120 parts of coal liquefaction asphalt, 110-130 parts of pretreated rubber powder, 8-12 parts of solubilizer, 15-30 parts of plasticizer, and 1-3 parts of stabilizer.

[0014] More optimally, the base asphalt is one of 70# road petroleum asphalt and 90# road petroleum asphalt; the stabilizer is one or a combination of elemental sulfur or sulfur-containing compounds; the solubilizer is one or a combination of phthalates, epoxy compounds, cycloalkane oils, aliphatic hydrocarbon oils, aromatic oils, turpentine, pine tar, and tung oil; the plasticizer is one or a combination of aliphatic dibasic acid esters, phthalates, phthalates, terephthalates, polybenzoates, benzoates, and polyol esters.

[0015] Preferably, the base asphalt is 70# road petroleum asphalt.

[0016] More optimally, the coal liquefaction asphalt (China Shenhua Coal to Oil Chemical Co., Ltd. of the State Energy Group) is the main by-product of coal liquefaction, with a yield of about 30% of the raw coal, an ash content of less than 15%, a softening point of 160~180°C, a mass change of less than 0.1%, and the residue after direct liquefaction of coal in the form of flakes or powder; the asphaltene content in the coal liquefaction asphalt is 60~85%, and the relative content of C and H elements is 70~90%.

[0017] Preferably, the coal liquefaction asphalt is in powder form.

[0018] More optimally, the preparation of the pretreated rubber powder includes the following steps: taking rubber powder, adding it to an internal mixer, mixing at 165-180°C for 10-20 minutes, extruding it through a screw extruder at 180-230°C, granulating it with an air-cooled die face pelletizing equipment, and crushing and grinding it to obtain a pretreated rubber powder of 80-100 mesh.

[0019] More optimally, the preparation of the pretreated rubber powder includes the following steps: taking rubber powder, adding it to an internal mixer, mixing it at 165°C for 15 minutes, extruding it through a screw extruder at 200°C, granulating it with an air-cooled die face pelletizing equipment, and crushing and grinding it to obtain a 100-mesh pretreated rubber powder.

[0020] More optimally, the rubber powder is waste rubber powder, which comes from waste tires.

[0021] More optimally, the ash content of the pretreated rubber powder is less than 8%, the carbon black content is greater than 28%, the rubber hydrocarbon content is greater than 48%, and the Mooney viscosity is 20-40M.

[0022] More optimally, the pretreated rubber powder is made by re-extruded granulation of rubber powder through a pure physical thermomechanical-twin screw extrusion method. During this process, the CS bonds in the waste rubber powder particles are broken, and desulfurization is completed. Under the action of the larger shear force during the desulfurization process, various filler systems in the waste rubber powder are destroyed, which promotes its adsorption and infiltration with the matrix asphalt.

[0023] More optimally, in step three, 10 to 15 parts of an asphalt modifier are further added to the second asphalt mixing system; the preparation of the asphalt modifier comprises the following steps: S1: uniformly mixing 1,2,4,5-tetrahydroxybenzene, 3-(4-bromophenyl)-6-methyl-2H-1,4-benzoxazine, 3-bromo-1-propylene, sodium carbonate and chloroform, pressurizing and heating to 70 to 80°C for reaction for 5 to 7 hours, and removing the solvent to obtain a modifier;

[0024] S2: Add reactive emulsifier, water and ethanol into a reaction vessel equipped with a stirrer, a heater, a thermometer and a reflux condenser, stir evenly, add ammonium persulfate aqueous solution and stir evenly, add butadiene, methacrylic acid, methyl acrylate, maleic anhydride, butyl acrylate, vinyltrimethoxysilane, methyl methacrylate, styrene, double-bond modified chitosan, modifier and dodecyl mercaptan, mix evenly, heat and react for 3 to 4 hours, remove the solvent, and obtain an asphalt modifier.

[0025] More optimally, step three includes the following steps: adding an asphalt modifier to the second asphalt mixing system at 180-185°C, and then slowly adding a stabilizer and mixing; high-speed shearing at 170-180°C to obtain a composite modified asphalt.

[0026] More optimally, in the modifier, the molar ratio of 1,2,4,5-tetrahydroxybenzene, 3-(4-bromophenyl)-6-methyl-2H-1,4-benzoxazine, 3-bromo-1-propylene, and sodium carbonate is 1: (1-1.5): (2.5-3): (3.5-4); the amount of chloroform added is 6-8 times the total mass of 1,2,4,5-tetrahydroxybenzene, 3-(4-bromophenyl)-6-methyl-2H-1,4-benzoxazine, 3-bromo-1-propylene, and sodium carbonate;

[0027] The ammonium persulfate aqueous solution comprises the following raw materials, calculated by weight: 1-2 parts of ammonium persulfate and 40-45 parts of water;

[0028] The asphalt modifier includes the following raw materials, calculated by mass: 3-4 parts of reactive emulsifier, 3-5 parts of butadiene, 8-10 parts of methacrylic acid, 20-25 parts of methyl acrylate, 3-5 parts of maleic anhydride, 10-15 parts of butyl acrylate, 10-15 parts of vinyltrimethoxysilane, 20-25 parts of methyl methacrylate, 6-8 parts of styrene, 6-8 parts of double-bond modified chitosan, 3-4 parts of modifier, and 0.1-0.2 parts of dodecyl mercaptan.

[0029] More optimally, the amount of chloroform added is 8 times the total mass of 1,2,4,5-tetrahydroxybenzene, 3-(4-bromophenyl)-6-methyl-2H-1,4-benzoxazine, 3-bromo-1-propylene, and sodium carbonate; the ammonium persulfate aqueous solution includes the following raw materials, calculated by mass: 1.5 parts of ammonium persulfate and 45 parts of water.

[0030] More optimally, the preparation of the double-bond modified chitosan includes the following steps: adding carboxymethyl chitosan to water and stirring evenly, maintaining 0-2°C, adding methacrylic anhydride dropwise, adjusting the pH to 7.5-8, stirring at 0-2°C for 20-24h, and post-treating to obtain double-bond modified chitosan.

[0031] More optimally, the post-treatment steps are: settling with ethanol, filtering the precipitate, washing the precipitate with ethanol three times, and drying.

[0032] More optimally, the double-bond modified chitosan comprises the following raw materials, calculated by weight: 2-3 parts of carboxymethyl chitosan, 150-180 parts of water, and 2-3 parts of methacrylic anhydride.

[0033] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: (1) The composite modified asphalt prepared by the present invention combines the low temperature and fatigue resistance advantages of rubber powder modified asphalt and the high dynamic modulus and high temperature characteristics of coal liquefaction asphalt. In addition, the present invention uses pretreated rubber powder and coal liquefaction asphalt to blend and replace part of the road petroleum asphalt, thereby reducing the amount of base asphalt used, increasing the utilization rate of coal liquefaction asphalt and waste tires in road engineering, solving the problems of asphalt resource shortage and environmental pollution, and realizing the effective recycling of solid waste, which has a positive impact on sustainable development. In addition, due to the low cost of raw materials and high cost performance, the technical solution reduces the project cost and has significant social and economic benefits. At the same time, the introduction of solubilizers and plasticizers optimizes the compatibility, overcomes the problems of low dynamic modulus of rubber powder modified asphalt and insufficient low temperature performance of coal liquefaction asphalt, and the composite modified asphalt significantly improves the anti-deformation and high temperature performance, enhances the road surface's resistance to rutting, water damage and durability, effectively copes with the rutting problem under heavy traffic conditions and extends the service life of the road. The composite modified asphalt preparation method provided by the present invention has precise control and is easy to operate, thereby ensuring an excellent modification effect and providing strong support for the production of high-performance composite modified asphalt.

[0034] (2) The present invention additionally adds an asphalt modifier, which is polymerized from double-bond monomers, wherein styrene and butadiene can improve the structural stability and weather resistance of the molecules; maleic anhydride improves the compatibility of various substances, thereby improving the system stability, elastic modulus and anti-rutting performance of the modified asphalt; the benzoxazine structure in the modifier has good heat resistance, mechanical properties and UV resistance, which helps to improve the weather resistance, stability and mechanical properties of the asphalt matrix; the double-bond modified chitosan has the effect of increasing viscosity and improving the elastic recovery ability of asphalt, and helps to increase steric hindrance and improve dispersibility; The amount of the asphalt modifier and double-bond modified chitosan added should not be too much. First of all, they contain multiple double bond structures that can participate in the reaction. The amount added determines the degree of branching of the asphalt modifier. An appropriate amount of branching structure helps to improve the mechanical properties of asphalt and can also form a network structure. It not only has good anti-migration properties, but also improves the anti-migration properties of other additives, thereby improving the overall aging resistance. However, if too much is added, first of all, due to its own large steric hindrance, it affects the polymerization of the asphalt modifier, resulting in a decrease in performance. It may also lead to excessive branching, which has a great impact on viscosity and processing performance, and instead leads to a decrease in performance. DETAILED DESCRIPTION

[0035] 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.

[0036] The following parts are by mass unless otherwise specified;

[0037] Example 1: Step 1: Heat 400 parts of base asphalt to 180°C, add 80 parts of coal liquefaction asphalt and 8 parts of aromatic oil solubilizer, stir at 2500r / min for 30min, and obtain a first asphalt mixing system;

[0038] Step 2: maintaining 180°C, adding 120 parts of pretreated rubber powder and 20 parts of dioctyl terephthalate plasticizer to the first asphalt mixture system and mixing, stirring at 2500 r / min for 30 min, and high-speed shearing at 7000 r / min for 15 min to obtain a second asphalt mixture system;

[0039] Step 3: Slowly add 2 parts of elemental sulfur stabilizer to the second asphalt mixing system at 180°C and mix, and high-speed shear at 4000r / min at 180°C for 10 minutes to obtain a composite modified asphalt.

[0040] Example 2: Step 1: Heat 400 parts of base asphalt to 175°C, add 100 parts of coal liquefaction asphalt and 11 parts of aliphatic hydrocarbon oil solubilizer, stir at 2500r / min for 25min, and obtain a first asphalt mixing system;

[0041] Step 2: maintaining 175°C, adding 115 parts of pretreated rubber powder and 22 parts of di-n-octyl phthalate plasticizer to the first asphalt mixture system and mixing, stirring at 2500 r / min for 25 min, and high-speed shearing at 6500 r / min for 10 min to obtain a second asphalt mixture system;

[0042] Step 3: Slowly add 1.5 parts of elemental sulfur stabilizer to the second asphalt mixing system at 180°C and mix, and high-speed shear at 3000r / min at 180°C for 8 minutes to obtain a composite modified asphalt.

[0043] Example 3: Step 1: Heat 400 parts of base asphalt to 180°C, add 90 parts of coal liquefaction asphalt and 10 parts of cycloparaffin oil solubilizer, stir at 2500r / min for 35min, and obtain a first asphalt mixing system;

[0044] Step 2: maintaining 180°C, adding 130 parts of pretreated rubber powder and 26 parts of polyol ester plasticizer to the first asphalt mixture system and mixing, stirring at 2500 r / min for 35 min, and high-speed shearing at 6500 r / min for 20 min to obtain a second asphalt mixture system;

[0045] Step 3: Slowly add 2.5 parts of sulfide stabilizer into the second asphalt mixture system at 180°C and mix, and high-speed shear at 4200 r / min at 180°C for 12 minutes to obtain a composite modified asphalt.

[0046] Example 4: Step 1: Heat 400 parts of base asphalt to 175°C, add 120 parts of coal liquefaction asphalt and 12 parts of aromatic oil solubilizer, stir at 2500r / min for 40min, and obtain a first asphalt mixing system;

[0047] Step 2: maintaining 175°C, adding 130 parts of pretreated rubber powder and 18 parts of polyol ester plasticizer to the first asphalt mixture system and mixing, stirring at 2500 r / min for 40 min, and high-speed shearing at 7500 r / min for 25 min to obtain a second asphalt mixture system;

[0048] Step 3: slowly add 3 parts of sulfide stabilizer into the second asphalt mixture system at 180°C and mix, and high-speed shear at 4500r / min at 180°C for 15 minutes to obtain a composite modified asphalt.

[0049] Example 5: Step 1: Heat 400 parts of base asphalt to 175°C, add 120 parts of coal liquefaction asphalt and 12 parts of aromatic oil solubilizer, stir at 2500r / min for 40min, and obtain a first asphalt mixing system;

[0050] Step 2: maintaining 175°C, adding 130 parts of pretreated rubber powder and 18 parts of polyol ester plasticizer to the first asphalt mixture system and mixing, stirring at 2500 r / min for 40 min, and high-speed shearing at 7500 r / min for 25 min to obtain a second asphalt mixture system;

[0051] Step 3: Add 12 parts of asphalt modifier to the second asphalt mixing system at 180° C., then slowly add 3 parts of sulfide stabilizer and mix, and high-speed shear at 4500 r / min at 180° C. for 15 minutes to obtain a composite modified asphalt;

[0052] Preparation method of asphalt modifier: S1: Take 3 parts of carboxymethyl chitosan, add 180 parts of water and stir evenly, keep 0°C, add 3 parts of methacrylic anhydride, adjust the pH to 8, stir at 0°C for 24 hours, and post-treat to obtain double-bond modified chitosan;

[0053] S2: 1,2,4,5-tetrahydroxybenzene, 3-(4-bromophenyl)-6-methyl-2H-1,4-benzoxazine, 3-bromo-1-propylene, sodium carbonate and chloroform are mixed evenly, pressurized and heated to 70-80°C, reacted for 5-7 hours, and the solvent is removed to obtain a modifier; the molar ratio of 1,2,4,5-tetrahydroxybenzene, 3-(4-bromophenyl)-6-methyl-2H-1,4-benzoxazine, 3-bromo-1-propylene and sodium carbonate is 1:1:3:4;

[0054] S3: Add 4 parts of reactive emulsifier, 420 parts of water and 80 parts of ethanol into a reaction vessel equipped with a stirrer, a heater, a thermometer and a reflux condenser, stir evenly at 92°C, add an aqueous solution of ammonium persulfate and stir evenly, add 5 parts of butadiene, 10 parts of methacrylic acid, 20 parts of methyl acrylate, 3 parts of maleic anhydride, 15 parts of butyl acrylate, 11 parts of vinyltrimethoxysilane, 25 parts of methyl methacrylate, 8 parts of styrene, 8 parts of double-bond modified chitosan, 4 parts of modifier and 0.2 parts of dodecyl mercaptan, mix evenly, react at 92°C for 4 hours, remove the solvent and obtain an asphalt modifier.

[0055] Comparative Example 1: Heat 400 parts of base asphalt to 180°C, add 120 parts of pretreated rubber powder and 8 parts of aromatic oil, 20 parts of dioctyl terephthalate, stir at 2500 r / min for 30 minutes, high-speed shear at 7000 r / min for 15 minutes, add 2 parts of elemental sulfur, mix, and high-speed shear at 4000 r / min at 180°C for 10 minutes to obtain a composite modified asphalt.

[0056] Comparative Example 2: Heat 400 parts of base asphalt to 180°C, add 140 parts of pretreated rubber powder and 10 parts of cycloalkane oil, 26 parts of polyol ester, stir at 2500 r / min for 30 minutes, high-speed shear at 7000 r / min for 15 minutes, add 2.5 parts of sulfide, mix, and high-speed shear at 4000 r / min at 180°C for 10 minutes to obtain a composite modified asphalt.

[0057] Comparative Example 3 (increasing the amount of double-bond modified chitosan and modifier added in the asphalt modifier, and the remaining method steps are consistent with Example 5): Step 1: Heat 400 parts of base asphalt to 175° C., add 120 parts of coal liquefaction asphalt and 12 parts of aromatic oil solubilizer, and stir at 2500 r / min for 40 minutes to obtain a first asphalt mixing system;

[0058] Step 2: maintaining 175°C, adding 130 parts of pretreated rubber powder and 18 parts of polyol ester plasticizer to the first asphalt mixture system and mixing, stirring at 2500 r / min for 40 min, and high-speed shearing at 7500 r / min for 25 min to obtain a second asphalt mixture system;

[0059] Step 3: Add 12 parts of asphalt modifier to the second asphalt mixing system at 180° C., then slowly add 3 parts of sulfide stabilizer and mix, and high-speed shear at 4500 r / min at 180° C. for 15 minutes to obtain a composite modified asphalt;

[0060] Preparation method of asphalt modifier: S1: Take 3 parts of carboxymethyl chitosan, add 180 parts of water and stir evenly, keep 0°C, add 3 parts of methacrylic anhydride, adjust the pH to 8, stir at 0°C for 24 hours, and post-treat to obtain double-bond modified chitosan;

[0061] S2: 1,2,4,5-tetrahydroxybenzene, 3-(4-bromophenyl)-6-methyl-2H-1,4-benzoxazine, 3-bromo-1-propylene, sodium carbonate and chloroform are mixed evenly, pressurized and heated to 70-80°C, reacted for 5-7 hours, and the solvent is removed to obtain a modifier; the molar ratio of 1,2,4,5-tetrahydroxybenzene, 3-(4-bromophenyl)-6-methyl-2H-1,4-benzoxazine, 3-bromo-1-propylene and sodium carbonate is 1:1:3:4;

[0062] S3: Add 4 parts of reactive emulsifier, 420 parts of water and 80 parts of ethanol into a reaction vessel equipped with a stirrer, a heater, a thermometer and a reflux condenser, stir evenly at 92°C, add an aqueous solution of ammonium persulfate and stir evenly, add 5 parts of butadiene, 10 parts of methacrylic acid, 20 parts of methyl acrylate, 3 parts of maleic anhydride, 15 parts of butyl acrylate, 11 parts of vinyltrimethoxysilane, 25 parts of methyl methacrylate, 8 parts of styrene, 12 parts of double bond modified chitosan, 6 parts of modifier and 0.2 parts of dodecyl mercaptan, mix evenly, react at 92°C for 4 hours, remove the solvent and obtain an asphalt modifier.

[0063] Comparative Example 4 (changing the amount of raw materials added in the modifier, and the other method steps are consistent with Example 5): Step 1: 400 parts of base asphalt are heated to 175° C., 120 parts of coal liquefaction asphalt and 12 parts of aromatic oil solubilizer are added, and stirred at 2500 r / min for 40 minutes to obtain a first asphalt mixing system;

[0064] Step 2: maintaining 175°C, adding 130 parts of pretreated rubber powder and 18 parts of polyol ester plasticizer to the first asphalt mixture system and mixing, stirring at 2500 r / min for 40 min, and high-speed shearing at 7500 r / min for 25 min to obtain a second asphalt mixture system;

[0065] Step 3: Add 12 parts of asphalt modifier to the second asphalt mixing system at 180° C., then slowly add 3 parts of sulfide stabilizer and mix, and high-speed shear at 4500 r / min at 180° C. for 15 minutes to obtain a composite modified asphalt;

[0066] Preparation method of asphalt modifier: S1: Take 3 parts of carboxymethyl chitosan, add 180 parts of water and stir evenly, keep 0°C, add 3 parts of methacrylic anhydride, adjust the pH to 8, stir at 0°C for 24 hours, and post-treat to obtain double-bond modified chitosan;

[0067] S2: 1,2,4,5-tetrahydroxybenzene, 3-(4-bromophenyl)-6-methyl-2H-1,4-benzoxazine, 3-bromo-1-propylene, sodium carbonate and chloroform are mixed evenly, pressurized and heated to 70-80°C, reacted for 5-7 hours, and the solvent is removed to obtain a modifier; the molar ratio of 1,2,4,5-tetrahydroxybenzene, 3-(4-bromophenyl)-6-methyl-2H-1,4-benzoxazine, 3-bromo-1-propylene and sodium carbonate is 1:3:1:4;

[0068] S3: Add 4 parts of reactive emulsifier, 420 parts of water and 80 parts of ethanol into a reaction vessel equipped with a stirrer, a heater, a thermometer and a reflux condenser, stir evenly at 92°C, add an aqueous solution of ammonium persulfate and stir evenly, add 5 parts of butadiene, 10 parts of methacrylic acid, 20 parts of methyl acrylate, 3 parts of maleic anhydride, 15 parts of butyl acrylate, 11 parts of vinyltrimethoxysilane, 25 parts of methyl methacrylate, 8 parts of styrene, 8 parts of double-bond modified chitosan, 4 parts of modifier and 0.2 parts of dodecyl mercaptan, mix evenly, react at 92°C for 4 hours, remove the solvent and obtain an asphalt modifier.

[0069] In the above examples, the test methods used are conventional methods unless otherwise specified; the raw materials used are commercially available unless otherwise specified, and the sources of the raw materials are as follows: aromatic oil (article number: yld-zy, Shandong Yonglida New Materials Technology Co., Ltd.); dioctyl terephthalate (CAS: 6422-86-2); elemental sulfur (CAS: 7704-34-9); aliphatic hydrocarbon oil (XK1096, Hubei Xinkang Pharmaceutical Chemical Co., Ltd.); di-n-octyl phthalate (CAS: 1 17-84-0); cycloalkane oil (Article No.: Tianjin Shifang 0015, Tianjin Shifang Chemical Co., Ltd. Nankai Branch); polyol ester (Article No.: Senfida 2776, Suzhou Senfida Chemical Co., Ltd.); sulfide (alkylphenol disulfide, CAS: 25085-50-1); carboxymethyl chitosan (Article No.: S30948, Shanghai Yuanye); methacrylic anhydride (CAS: 760-93-0); ethanol (CAS: 64-17-5); 1,2,4,5-tetrahydroxybenzene ( CAS: 636-32-8); 3-(4-bromophenyl)-6-methyl-2H-1,4-benzoxazine (CAS: 351003-33-3); 3-bromo-1-propylene (CAS: 106-95-6); sodium carbonate (Product No.: S24152, Shanghai Yuanye); chloroform (CAS: 67-66-3); ammonium persulfate (CAS: 7727-54-0); reactive emulsifier (polystyrene sulfonic acid, Product No. 8598479, Kanos); butadiene (CA S: 106-99-0); methacrylic acid (CAS: 79-41-4); methyl acrylate (CAS: 96-33-3); maleic anhydride (CAS: 108-31-6); butyl acrylate (CAS: 141-32-2); vinyl trimethoxysilane (CAS: 2768-02-7); methyl methacrylate (CAS: 80-62-6); styrene (CAS: 100-42-5); dodecyl mercaptan (CAS: 112-55-0).

[0070] Experiment: (1) The composite modified asphalt prepared in Examples 1 to 5 and Comparative Examples 1 to 2 was tested for its performance; see Table 1 and Table 2;

[0071] Table 1:

[0072] project Needle penetration 0.1cm Softening point℃ Elongation cm Viscosity Pa·s180℃ Needle penetration ratio% Residual elongation cm Quality change% Example 1 26 90 11 2.4 82 8 0.146 Example 2 23 90 14 2.6 84 10 0.169 Example 3 24 95 12 2.5 85 8 0.232 Example 4 19 >100 10 2.6 90 6 0.287 Example 5 20 >100 16 2.6 93 13 0.201 Comparative Example 1 46 66 18 3.1 80 13 0.511 Comparative Example 2 48 70 20 3.3 82 13 0.421

[0073] Table 2:

[0074] project Dynamic stability / (times•min-1) Freeze-thaw splitting strength ratio Maximum bending strain / με Dynamic modulus MPa Mixing temperature℃ Void rate% Example 1 9507 90.2 2944 15400 165 3.7 Example 2 9276 90.5 2868 16500 165 3.8 Example 3 9423 91 2989 16800 160 3.7 Example 4 9664 90.1 2878 17000 162 3.7 Example 5 10833 94 3191 18525 165 3.7 Comparative Example 1 6874 83.4 3392 9800 180 4.0 Comparative Example 2 7023 82.1 3218 9780 180 3.9

[0075] It can be seen from the above table that the penetration and ductility of the composite modified asphalt of the present invention are significantly reduced, and the softening point is significantly improved compared with the comparative example. The viscosity at 180°C decreases to a certain extent, indicating that the high-temperature performance of the composite modified asphalt of the present invention is significantly improved compared with the conventional rubber powder modified asphalt of the comparative example; the low-temperature ductility is reduced, which is caused by the high asphaltene and ash content in the coal liquefaction asphalt. However, due to the adjustment of the solubilizer and the plasticizer, it is still within the product index range. The viscosity of the modified asphalt of the embodiment is lower than that of the modified asphalt of the comparative example, indicating that the composite modified asphalt provided by the present invention has good construction and workability, can reduce the mixing temperature, and play a role in energy conservation and emission reduction.

[0076] The penetration ratio, residual ductility and mass change are asphalt indicators after aging. It can be seen from Table 1 that the above three indicators of the embodiments of the present invention are better than those of the comparative examples, indicating that the anti-aging performance of the composite modified asphalt of the present invention is better than that of the rubber powder modified asphalt of the comparative example.

[0077] The mixture properties of the embodiment and the comparative example are shown in Table 2. It can be seen from Table 2 that the dynamic stability and freeze-thaw splitting strength ratio of the composite modified asphalt prepared by the method proposed in the embodiment, which reflect the high temperature performance and water stability of the mixture, are higher than the corresponding indicators in the comparative example. The maximum bending strain of the asphalt mixture in the embodiment is lower than that in the comparative example, indicating that the addition of coal liquefaction asphalt has a certain negative impact on the low temperature performance of the asphalt mixture. The addition of solubilizers and plasticizers can reduce the impact of coal liquefaction asphalt on the low temperature performance of the mixture. It is still kept within the range of the index requirements (>2800με), but the addition of coal liquefaction asphalt greatly improves the dynamic modulus of the asphalt mixture, reaching the requirements of high modulus asphalt (>14000MPa). The fatigue resistance of the asphalt mixture is greatly enhanced, the rutting resistance, water damage resistance and durability of the road surface are enhanced, the maintenance cycle and the service life of the road are extended, and significant social and economic benefits are achieved.

[0078] (2) Example 5 is based on Example 4, with the addition of asphalt modifier, and the ductility, dynamic stability, freeze-thaw splitting strength ratio, maximum bending tensile strain, and dynamic modulus are significantly improved. It can be seen from the penetration ratio, residual ductility and mass change that its aging resistance is significantly enhanced; Comparative Examples 3-4 are set based on Example 5. Due to process changes, the performance is reduced, as shown in Table 3;

[0079] Table 3:

[0080] Elongation cm Residual elongation cm Quality change% Example 5 16 13 0.201 Comparative Example 3 13 10 0.248 Comparative Example 4 14 10 0.241

[0081] In summary, the composite modified asphalt prepared by the present invention has excellent performance and meets the requirements of sustainable development.

[0082] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A composite modified asphalt based on coal liquefaction asphalt and rubber powder, characterized in that: The invention comprises the following raw materials, calculated by weight: 350-450 parts of base asphalt, 80-120 parts of coal liquefaction asphalt, 110-130 parts of pretreated rubber powder, 8-12 parts of solubilizer, 15-30 parts of plasticizer and 1-3 parts of stabilizer.

2. The method for preparing a composite modified asphalt based on coal liquefaction asphalt and rubber powder according to claim 1, characterized in that: The method comprises the following steps: Step 1: heating the base asphalt to 170-180° C., adding coal liquefied asphalt and a solubilizing agent, and stirring to obtain a first asphalt mixing system; Step 2: maintaining the temperature at 170-180°C, adding the pretreated rubber powder and the plasticizer to the first asphalt mixture system, mixing, stirring, and high-speed shearing to obtain a second asphalt mixture system; Step 3: slowly add the stabilizer to the second asphalt mixing system at 180-185°C and mix, and high-speed shear at 170-180°C to obtain a composite modified asphalt.

3. The method for preparing a composite modified asphalt based on coal liquefaction asphalt and rubber powder according to claim 1, characterized in that: The preparation of the pretreated rubber powder comprises the following steps: Take rubber powder, add it into an internal mixer, mix it at 165-180℃ for 10-20 minutes, extrude it through a screw extruder at 180-230℃, granulate it with an air-cooled die face pelletizing equipment, crush and grind it, and then process it to obtain 80-100 mesh pretreated rubber powder.

4. The method for preparing a composite modified asphalt based on coal liquefaction asphalt and rubber powder according to claim 2, characterized in that: The stirring time in step one is 10-40 min, and the stirring rate is 1000-4000 r / min; the stirring time in step two is 10-40 min, and the stirring rate is 1000-4000 r / min; the high-speed shearing time in step two is 5-30 min, and the shearing rate is 2000-8000 r / min; the high-speed shearing time in step three is 5-30 min, and the shearing rate is 2000-6000 r / min.

5. The method for preparing a composite modified asphalt based on coal liquefaction asphalt and rubber powder according to claim 2, characterized in that: The matrix asphalt is one of 70# road petroleum asphalt and 90# road petroleum asphalt; the stabilizer is one or a combination of elemental sulfur or sulfur-containing compounds; the solubilizer is one or a combination of phthalates, epoxy compounds, cycloalkane oil, aliphatic hydrocarbon oil, aromatic oil, turpentine, pine tar, and tung oil; the plasticizer is one or a combination of aliphatic dibasic acid esters, phthalates, phthalates, terephthalates, polybenzoates, benzoates, and polyol esters.

6. The method for preparing a composite modified asphalt based on coal liquefaction asphalt and rubber powder according to claim 2, characterized in that: In step 3, 10 to 15 parts of an asphalt modifier are added to the second asphalt mixing system to obtain a composite modified asphalt; the preparation of the asphalt modifier comprises the following steps: S1: 1,2,4,5-tetrahydroxybenzene, 3-(4-bromophenyl)-6-methyl-2H-1,4-benzoxazine, 3-bromo-1-propylene, sodium carbonate and chloroform are uniformly mixed, pressurized and heated to 70 to 80° C. for reaction for 5 to 7 hours, and the solvent is removed to obtain a modifier; S2: Add reactive emulsifier, water and ethanol into the reaction container, stir evenly, add ammonium persulfate aqueous solution and stir evenly, add butadiene, methacrylic acid, methyl acrylate, maleic anhydride, butyl acrylate, vinyl trimethoxysilane, methyl methacrylate, styrene, double bond modified chitosan, modifier and dodecyl mercaptan, mix evenly, heat and react for 3-4 hours, remove the solvent and obtain the asphalt modifier.

7. The method for preparing a composite modified asphalt based on coal liquefaction asphalt and rubber powder according to claim 6, characterized in that: In the modifier, the molar ratio of 1,2,4,5-tetrahydroxybenzene, 3-(4-bromophenyl)-6-methyl-2H-1,4-benzoxazine, 3-bromo-1-propylene and sodium carbonate is 1: (1-1.5): (2.5-3): (3.5-4); the ammonium persulfate aqueous solution includes the following raw materials, calculated by weight: 1-2 parts of ammonium persulfate and 40-45 parts of water; the asphalt modifier includes the following raw materials, calculated by weight: 3-4 parts of reactive emulsifier, 3-5 parts of butadiene, 8-10 parts of methacrylic acid, 20-25 parts of methyl acrylate, 3-5 parts of maleic anhydride, 10-15 parts of butyl acrylate, 10-15 parts of vinyltrimethoxysilane, 20-25 parts of methyl methacrylate, 6-8 parts of styrene, 6-8 parts of double-bond modified chitosan, 3-4 parts of modifier and 0.1-0.2 parts of dodecyl mercaptan.

8. The method for preparing a composite modified asphalt based on coal liquefaction asphalt and rubber powder according to claim 6, characterized in that: The preparation of the double bond modified chitosan comprises the following steps: Take carboxymethyl chitosan and add it into water, stir evenly, maintain 0~2℃, add methacrylic anhydride dropwise, adjust the pH to 7.5~8, stir at 0~2℃ for 20~24h, and post-treat to obtain double-bond modified chitosan.

9. The method for preparing a composite modified asphalt based on coal liquefaction asphalt and rubber powder according to claim 8, characterized in that: The double-bond modified chitosan comprises the following raw materials, calculated by weight: 2-3 parts of carboxymethyl chitosan, 150-180 parts of water, and 2-3 parts of methacrylic anhydride.