A composite modified asphalt concrete and its preparation method

Abstract

The present invention discloses a composite modified asphalt concrete and a preparation method thereof, belonging to the technical field of asphalt mixtures. The present invention comprises the following components by weight: 4-6 parts of 90# asphalt, 1-5 parts of modified bamboo fiber, 70-80 parts of coarse aggregate coated with a chlorosilicon composite material, and 15-30 parts of fine aggregate coated with a chlorosilicon composite material. The present invention prepares a chlorosilicon composite material containing chlorosilicon, polybenzene rings, and multiple branched chains, coats the coarse aggregate and the fine aggregate with it, connects bamboo fiber and polychlorotrifluoroethylene with 2-methyl-4-chloropropionic acid to obtain modified bamboo fiber, and incorporates the aggregate coated with the chlorosilicon composite material and the modified bamboo fiber into the asphalt, thereby improving the high and low temperature resistance and waterproof performance of the composite modified asphalt concrete.

Description

Technical Field

[0001] The present invention belongs to the technical field of asphalt mixtures, and particularly relates to a composite modified asphalt concrete and a preparation method thereof. Background Art

[0002] As a common pavement form in highway construction, the research and application of asphalt pavement materials have always been widely concerned. How to improve the high and low temperature resistance and waterproof performance of asphalt pavement is a technical problem that needs to be solved urgently. In addition, traditional asphalt pavement is a dense asphalt mixture, and it is easy to cause waterlogging disasters when the drainage system is not timely during heavy rain. Asphalt mixtures not only need to have high water resistance, but also need to have good water permeability to ensure the normal use of asphalt pavement.

[0003] Patent application CN104058638A discloses an asphalt mixture, which improves the high temperature and low temperature resistance of the prepared asphalt mixture by adding basalt fibers. However, basalt fibers themselves are inorganic materials and have poor compatibility with the asphalt matrix. Excessive filling of inorganic materials in asphalt materials will affect the water permeability of asphalt mixtures themselves.

[0004] In view of the technical defects in this regard, a solution is proposed now. Summary of the Invention

[0005] The purpose of the present invention is to provide a composite modified asphalt concrete and a preparation method thereof to solve the technical defects proposed in the background art.

[0006] The purpose of the present invention can be achieved by the following technical solutions: A composite modified asphalt concrete, comprising the following components by weight: 4-6 parts of 90# asphalt, 1-5 parts of modified bamboo fibers, 70-80 parts of coarse aggregate coated with chlorosilicon composite material, and 15-30 parts of fine aggregate coated with chlorosilicon composite material.

[0007] The composite modified asphalt concrete prepared by the present invention comprises asphalt, coarse and fine aggregates coated with chlorosilicon composite material, and modified bamboo fibers.

[0008] Further, the chlorosilicon composite material is prepared by the following steps:

[0009] S1. Mix and stir polystyrene, benzoyl peroxide and toluene, heat up to 60-70 °C under a nitrogen atmosphere, then dropwise add 15-20 mL of vinyltrimethoxysilane. After the dropping is completed, activate at this temperature for 30-60 min to obtain a reaction system; then distill the reaction system under reduced pressure to prepare a trimethoxysilane / polystyrene solid;

[0010] The reaction formula of polystyrene and vinyltrimethoxysilane is as follows:

[0011]

[0012] The reaction principle of polystyrene and vinyltrimethoxysilane is as follows:

[0013] In the present invention, vinyltrimethoxysilane is used as a polymerization monomer. Under the action of the catalyst benzoyl peroxide, polystyrene and vinyltrimethoxysilane undergo an addition polymerization reaction to prepare solid trimethoxysilane / polystyrene.

[0014] S2. Trimethoxysilane / polystyrene, phosphorus trichloride and acetone are mixed evenly, and then aluminum chloride is added. The temperature is raised to 30 - 40 °C, and the mixture is reacted at 100 r / min for 2 - 3 h. Then the temperature is raised to 80 - 85 °C and reacted for 2 h to obtain a solid. The solid is washed three times with deionized water to obtain a modified silicone material;

[0015] The reaction principle of trimethoxysilane / polystyrene and phosphorus trichloride is as follows:

[0016] Using Lewis acid aluminum chloride as a catalyst, trimethoxysilane / polystyrene and phosphorus trichloride undergo a nucleophilic substitution reaction to prepare a modified silicone material.

[0017] The reaction formula of trimethoxysilane / polystyrene and phosphorus trichloride is as follows:

[0018]

[0019] S3. 3,3,3'-Trihydroxytriphenoxysilane and the modified silicone material are mixed, and the temperature is raised to 120 - 140 °C and reacted for 1 - 2 h to obtain a solid chlorosilicon composite material.

[0020] The reaction principle of 3,3,3'-trihydroxytriphenoxysilane and the chlorosilicon composite material is as follows:

[0021] The phenolic hydroxyl group of 3,3,3'-trihydroxytriphenoxysilane and the chloride ions in the modified silicone material undergo a nucleophilic substitution reaction again to prepare a chlorosilicon composite material.

[0022] The reaction formula of 3,3,3'-trihydroxytriphenoxysilane and the chlorosilicon composite material is as follows:

[0023]

[0024] Furthermore, the dosage ratio of polystyrene, benzoyl peroxide, toluene and vinyltrimethoxysilane is 10 - 20 g : 0.1 g : 200 mL : 15 - 20 mL; the pressure of vacuum distillation is 100 Pa, and the temperature of vacuum distillation is 110 - 120 °C.

[0025] Further, the dosage ratio of trimethoxysilane / polystyrene, phosphorus trichloride, acetone and aluminum chloride is 30 - 40 g: 10 - 13 g: 200 mL: 0.1 g; in step S3, 3 ’ 3 ’ 3 ’ - The dosage ratio of tris - hydroxytriphenoxysilane and the modified silicone material is 15 - 20 g: 40 - 50 g.

[0026] Further, the coated coarse aggregate of the chlorosilicon composite material is prepared by the following steps:

[0027] A1. Crush, grind and sieve basalt to obtain primary coarse aggregate particles with a particle size of 10 - 15 mm and secondary coarse aggregate particles with a particle size of 5 - 10 mm respectively; by weight, mix 10 parts of the primary coarse aggregate particles and 10 parts of the secondary coarse aggregate particles evenly to obtain the coarse aggregate;

[0028] A2. By weight, mix 5 parts of the coarse aggregate and 100 - 110 parts of the chlorosilicon composite material evenly, and then dry at 150 - 160 °C for 3 - 4 h to obtain the coated recycled coarse aggregate.

[0029] Further, the coated fine aggregate of the chlorosilicon composite material is prepared by the following steps:

[0030] Grind and sieve silica fume to obtain fine aggregate with a particle size of 1 - 3 mm; by weight, mix 3 parts of the fine aggregate with a particle size of 1 - 3 mm and 100 - 110 parts of the chlorosilicon composite material, and then dry at 150 - 160 °C for 3 - 4 h to obtain the fine aggregate coated with chlorosilicon resin.

[0031] In the asphalt mixture, the aggregate gradation has a very important impact on the performance, strength and durability of the concrete, etc. In the present invention, basalt with a particle size of 10 - 15 mm is used as the primary coarse aggregate particles, basalt with a particle size of 5 - 10 mm is used as the secondary coarse aggregate particles, and silica fume with a particle size of 1 - 3 mm is used as the fine aggregate. The above - mentioned aggregate particles are all treated by coating with chlorosilicon resin.

[0032] Further, the preparation method of the modified bamboo fiber includes the following steps:

[0033] B1. Mix bamboo fiber and 1% wt of NaOH solution, soak at room temperature for 1 - 2 h, and then filter to obtain alkalized bamboo fiber; wash the alkalized bamboo fiber three times with deionized water, dry at 70 - 80 °C for 2 - 3 h to obtain dried bamboo fiber; grind the dried bamboo fiber to obtain bamboo fiber powder with a particle size of 300 mesh, 400 mesh or 500 mesh;

[0034] B2. Mix 2-methyl-4-chloropropionic acid and ethanol to obtain a 2-methyl-4-chloropropionic acid solution. Then add bamboo fiber powder to the 2-methyl-4-chloropropionic acid solution, mix and stir to obtain a mixed solid-liquid. Then add polychlorotrifluoroethylene to the mixed solid-liquid and react at 70 - 80 °C for 1 - 2 h to obtain modified bamboo fiber.

[0035] The main components of bamboo fiber are cellulose, hemicellulose and lignin, and there are a large number of hydroxyl groups. Polychlorotrifluoroethylene is a chain crystalline polymer with a -CF2-CFCl- structure. The presence of fluorine atoms destroys the symmetry of the molecular structure of polychlorotrifluoroethylene and improves the reactivity of the polymer. As a polyfunctional monomer, the carboxyl group and chloride ion of 2-methyl-4-chloropropionic acid can react with the hydroxyl groups of bamboo fiber. The carboxyl group of 2-methyl-4-chloropropionic acid can react with the hydroxyl groups of bamboo fiber, thus becoming a reaction intermediate bridge to improve the adsorption capacity of bamboo fiber and polychlorotrifluoroethylene, and then the modified bamboo fiber is prepared.

[0036] Furthermore, in step B1, the dosage ratio of bamboo fiber to NaOH solution is 10 g:100 mL; in step B2, the dosage ratio of 2-methyl-4-chloropropionic acid to ethanol is 20 - 30 g:50 mL, and the dosage of polychlorotrifluoroethylene is 10 g.

[0037] The present invention also provides a preparation method of a composite modified asphalt concrete, comprising the following steps:

[0038] Heat 90# asphalt at 135 - 140 °C until it becomes completely fluid, and then add the modified bamboo fiber, coarse aggregate coated with chlorosilicon composite material, and fine aggregate coated with chlorosilicon composite material to the 90# asphalt, shear and stir, and mix evenly to obtain the composite modified asphalt concrete.

[0039] Furthermore, the speed of shear stirring is 2500 - 3000 r / min, the time of shear stirring is 1 - 2 h, and the temperature of shear stirring is 140 - 145 °C.

[0040] The present invention has the following beneficial effects:

[0041] 1. The present invention coats coarse aggregate and fine aggregate with a chlorosilicon composite material, thereby improving the high and low temperature resistance and waterproofness of the prepared composite modified asphalt mixture. Polystyrene, as a single straight-chain polymer compound, itself has certain waterproofness and high and low temperature resistance; in the present invention, polystyrene and vinyltrimethoxysilane are subjected to addition polymerization to introduce silicon element, further improving its own waterproofness and high and low temperature resistance. However, linear polymer materials are prone to the problem of long-chain entanglement. In order to introduce branched chains into trimethoxysilane / polystyrene, the present invention first reacts trimethoxysilane / polystyrene with phosphorus trichloride to introduce chlorine element into trimethoxysilane / polystyrene, and then 3,3,3-trihydroxytriphenoxysilane undergoes nucleophilic substitution with the chlorine element, thereby preparing a composite organosilicon material with branched chains and improving the stability of the polymer material itself. In addition, the introduced branched-chain trimethoxysilane / polystyrene contains a polybenzene ring structure and silicon element, which is beneficial to further improving its own high and low temperature resistance. The present invention utilizes the polyphenolic hydroxyl group of 3,3,3-trihydroxytriphenoxysilane to undergo nucleophilic substitution reaction with halogen, thereby avoiding the pollution of halogen to the asphalt mixture after the chlorosilicon composite material is incorporated into the asphalt mixture. And the excess phenolic hydroxyl groups in 3,3,3-trihydroxytriphenoxysilane can improve the compatibility between the prepared chlorosilicon composite material and coarse aggregate and fine aggregate.

[0042] 2. Modified bamboo fibers are added to the composite modified asphalt concrete prepared by the present invention. The bamboo fibers treated with alkali solution can eliminate a certain amount of hemicellulose, lignin, etc. in the bamboo fibers; in addition, alkali treatment usually reduces the diameter of the fibers, thereby enabling the fibers to have a larger matrix contact area and effectively improving the adhesion performance between the bamboo fibers and asphalt, coarse aggregate and fine aggregate. The present invention modifies bamboo fibers and polytetrafluoroethylene together with 2-methyl-4-chloropropionic acid; the polyhydroxyl groups on the surface of the bamboo fibers can react with the chloride ions and carboxyl functional groups of 2-methyl-4-chloropropionic acid, and the chloride ions in polytetrafluoroethylene can react with the carboxyl group of 2-methyl-4-chloropropionic acid, thereby using 2-methyl-4-chloropropionic acid as a reaction connecting bridge to composite the bamboo fibers and polytetrafluoroethylene; polychlorotrifluoroethylene is a chain-like crystalline polymer with a -CF2-CFCl- structure and itself has good temperature resistance and waterproofness, thereby further improving the high and low temperature resistance and waterproofness of the prepared composite modified asphalt mixture. The bamboo fibers and asphalt form a blend, and through the adsorption and stabilization effect of the bamboo fibers and the fiber interface strengthening effect, the high temperature stability and low temperature crack resistance of the asphalt mixture are improved. Detailed implementation mode

[0043] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0044] Example 1

[0045] This example provides a preparation method of a chlorosilicon composite material for composite modified asphalt concrete, including the following steps:

[0046] 1. Add 10 g of polystyrene, 0.1 g of benzoyl peroxide and 200 mL of toluene into a 500 mL three-necked flask. The three-necked flask is filled with nitrogen, and then the mixture is stirred and heated to 60 °C. Use a constant pressure dropping funnel to drop 15 mL of vinyltrimethoxysilane. After the dropping is completed, activate for 30 min at this temperature to obtain a reaction system; then carry out vacuum distillation on the reaction system to prepare a trimethoxysilane / polystyrene solid; the pressure of the vacuum distillation is 100 Pa, and the temperature of the vacuum distillation is 110 °C.

[0047] 2. Add 30 g of trimethoxysilane / polystyrene, 10 g of phosphorus trichloride and 200 mL of acetone into a four-necked flask, mix evenly, then add 0.1 g of aluminum chloride into the four-necked flask, heat up to 30 °C, and react with mixing at 100 r / min for 2 h, then heat up to 80 °C and react for 2 h to obtain a solid; wash the solid three times with deionized water to obtain a modified silicone material.

[0048] 3. Mix 15 g of 3’3’3’-trihydroxytriphenoxysilane and 40 g of the modified silicone material, add them into a beaker, heat up to 120 °C, and react for 1 h to prepare a chlorosilicon composite material.

[0049] Example 2

[0050] This example provides a preparation method of a chlorosilicon composite material for composite modified asphalt concrete, including the following steps:

[0051] 1. Add 15 g of polystyrene, 0.1 g of benzoyl peroxide and 200 mL of toluene into a 500 mL three-necked flask. The three-necked flask is filled with nitrogen, and then the mixture is stirred and heated to 66 °C. Use a constant pressure dropping funnel to drop 16 mL of vinyltrimethoxysilane. After the dropping is completed, activate for 50 min at this temperature to obtain a reaction system; then carry out vacuum distillation on the reaction system to prepare a trimethoxysilane / polystyrene solid; the pressure of the vacuum distillation is 100 Pa, and the temperature of the vacuum distillation is 115 °C.

[0052] 2. 35 g of trimethoxysilane / polystyrene, 12 g of phosphorus trichloride and 200 mL of acetone were added to a four-necked flask and mixed evenly. Then, 0.1 g of aluminum chloride was added to the four-necked flask, and the temperature was raised to 33 °C. The mixture was reacted at 100 r / min for 2.5 h, and then the temperature was raised to 82 °C and reacted for 2 h to obtain a solid. The solid was washed three times with deionized water to obtain a modified silicone material.

[0053] 3. 16 g of 3’3’3’-trihydroxytriphenoxysilane and 44 g of the modified silicone material were mixed and added to a beaker. The temperature was raised to 130 °C and reacted for 1.5 h to prepare a chlorosilicon composite material.

[0054] Example 3

[0055] This example provides a preparation method of a chlorosilicon composite material for composite modified asphalt concrete, including the following steps:

[0056] 1. 20 g of polystyrene, 0.1 g of dibenzoyl peroxide and 200 mL of toluene were added to a 500 mL three-necked flask. The three-necked flask was filled with nitrogen, and then the mixture was stirred and heated to 70 °C. 20 mL of vinyltrimethoxysilane was added dropwise using a constant pressure dropping funnel. After the addition was complete, it was activated at this temperature for 60 min to obtain a reaction system. Then, the reaction system was subjected to vacuum distillation to prepare a trimethoxysilane / polystyrene solid. The pressure of the vacuum distillation was 100 Pa, and the temperature of the vacuum distillation was 120 °C.

[0057] 2. 40 g of trimethoxysilane / polystyrene, 13 g of phosphorus trichloride and 200 mL of acetone were added to a four-necked flask and mixed evenly. Then, 0.1 g of aluminum chloride was added to the four-necked flask, and the temperature was raised to 40 °C. The mixture was reacted at 100 r / min for 2 - 3 h, and then the temperature was raised to 85 °C and reacted for 2 h to obtain a solid. The solid was washed three times with deionized water to obtain a modified silicone material.

[0058] 3. 20 g of 3’3’3’-trihydroxytriphenoxysilane and 50 g of the modified silicone material were mixed and added to a beaker. The temperature was raised to 140 °C and reacted for 2 h to prepare a chlorosilicon composite material.

[0059] Example 4

[0060] This example provides a preparation method of a chlorosilicon composite material-coated aggregate for composite modified asphalt concrete, including the following steps:

[0061] 1. Crush, grind, and sieve basalt to obtain primary coarse aggregate particles with a particle size of 10 mm and secondary coarse aggregate particles with a particle size of 5 mm respectively; mix 10 parts of the primary coarse aggregate particles and 10 parts of the secondary coarse aggregate particles evenly by weight to obtain coarse aggregate; grind and sieve silica fume to obtain fine aggregate with a particle size of 1 mm.

[0062] 2. Mix 5 parts of the coarse aggregate and 100 parts of the chlorosilicon composite material, stir well, and then dry in an oven at 150 °C for 3 h to obtain coarse aggregate coated with chlorosilicon resin; mix 3 parts of the fine aggregate with a particle size of 1 mm and 100 parts of the chlorosilicon composite material, stir well, and then dry in an oven at 150 °C for 3 h to obtain fine aggregate coated with chlorosilicon resin.

[0063] Example 5

[0064] This example provides a preparation method of aggregate coated with chlorosilicon composite material for composite modified asphalt concrete, including the following steps:

[0065] 1. Crush, grind, and sieve basalt to obtain primary coarse aggregate particles with a particle size of 12 mm and secondary coarse aggregate particles with a particle size of 8 mm respectively; mix 10 parts of the primary coarse aggregate particles and 10 parts of the secondary coarse aggregate particles evenly by weight to obtain coarse aggregate; grind and sieve silica fume to obtain fine aggregate with a particle size of 3 mm.

[0066] 2. Mix 5 parts of the coarse aggregate and 105 parts of the chlorosilicon composite material, stir well, and then dry in an oven at 155 °C for 3.3 h to obtain coarse aggregate coated with chlorosilicon resin; mix 3 parts of the fine aggregate with a particle size of 2 mm and 100 parts of the chlorosilicon composite material, stir well, and then dry in an oven at 155 °C for 3.3 h to obtain fine aggregate coated with chlorosilicon resin.

[0067] Example 6

[0068] This example provides a preparation method of aggregate coated with chlorosilicon composite material for composite modified asphalt concrete, including the following steps:

[0069] 1. Crush, grind, and sieve basalt to obtain primary coarse aggregate particles with a particle size of 15 mm and secondary coarse aggregate particles with a particle size of 10 mm respectively; mix 10 parts of the primary coarse aggregate particles and 10 parts of the secondary coarse aggregate particles evenly by weight to obtain coarse aggregate; grind and sieve silica fume to obtain fine aggregate with a particle size of 3 mm.

[0070] 2. Mix 5 parts of coarse aggregate and 110 parts of chlorosilicon composite material, and mix thoroughly. Then dry in an oven at 160 °C for 4 h to obtain coarse aggregate coated with chlorosilicon resin. Mix 3 parts of fine aggregate with a particle size of 3 mm and 100 parts of chlorosilicon composite material, mix thoroughly, and then dry in an oven at 160 °C for 4 h to obtain fine aggregate coated with chlorosilicon resin.

[0071] Example 7

[0072] This example provides a method for preparing modified bamboo fiber for composite modified asphalt concrete, including the following steps:

[0073] 1. Mix 10 g of bamboo fiber with 100 mL of 1% wt NaOH solution, soak at room temperature for 1 h, then filter to obtain a solid, which is the alkalized bamboo fiber. Wash the alkalized bamboo fiber three times with deionized water, then put it into a vacuum oven and dry at 70 °C for 2 h to obtain the dried bamboo fiber. Then grind the dried bamboo fiber with a grinder to obtain bamboo fiber powder with a particle size of 300 mesh.

[0074] 2. Mix 10 g of 2-methyl-4-chloropropionic acid and 50 mL of ethanol and add them to a beaker to obtain a 2-methyl-4-chloropropionic acid solution. Then add 20 g of bamboo fiber powder to 50 mL of the 2-methyl-4-chloropropionic acid solution, mix and stir at 100 r / min for 20 min to prepare a mixed solid-liquid. Then add 10 g of polychlorotrifluoroethylene to the mixed solid-liquid, transfer the beaker to a water bath, heat up to 70 °C, react for 1 h, then filter to obtain the modified bamboo fiber.

[0075] Example 8

[0076] This example provides a method for preparing modified bamboo fiber for composite modified asphalt concrete, including the following steps:

[0077] 1. Mix 10 g of bamboo fiber with 100 mL of 1% wt NaOH solution, soak at room temperature for 1.6 h, then filter to obtain a solid, which is the alkalized bamboo fiber. Wash the alkalized bamboo fiber three times with deionized water, then put it into a vacuum oven and dry at 70 °C for 2 h to obtain the dried bamboo fiber. Then grind the dried bamboo fiber with a grinder to obtain bamboo fiber powder with a particle size of 400 mesh.

[0078] 2. Mix 10 g of mecoprop and 50 mL of ethanol in a beaker to obtain a mecoprop solution. Then add 25 g of bamboo fiber powder to 55 mL of the mecoprop solution, mix and stir at 100 r / min for 20 min to prepare a mixed solid-liquid. Then add 10 g of polychlorotrifluoroethylene to the mixed solid-liquid, transfer the beaker to a water bath, heat up to 75 °C, react for 1.5 h, and then filter to obtain modified bamboo fiber.

[0079] Example 9

[0080] This example provides a preparation method of modified bamboo fiber for composite modified asphalt concrete, including the following steps:

[0081] 1. Mix 10 g of bamboo fiber and 100 mL of 1% wt NaOH solution, soak at room temperature for 2 h, and then filter to obtain a solid, which is the alkalized bamboo fiber. Wash the alkalized bamboo fiber three times with deionized water, then put it into a vacuum oven and dry at 80 °C for 3 h to obtain dried bamboo fiber. Then grind the dried bamboo fiber with a grinder to obtain bamboo fiber powder with a particle size of 500 mesh.

[0082] 2. Mix 10 g of mecoprop and 50 mL of ethanol in a beaker to obtain a mecoprop solution. Then add 30 g of bamboo fiber powder to 50 mL of the mecoprop solution, mix and stir at 100 r / min for 20 min to prepare a mixed solid-liquid. Then add 10 g of polychlorotrifluoroethylene to the mixed solid-liquid, transfer the beaker to a water bath, heat up to 80 °C, react for 2 h, and then filter to obtain modified bamboo fiber.

[0083] Example 10

[0084] This example provides a preparation method of composite modified asphalt concrete, including the following steps:

[0085] By weight, 4 parts of 90# asphalt are heated at 135 °C until it becomes completely fluid, and then 1 part of the modified bamboo fiber prepared in Example 7, 70 parts of the coarse aggregate coated with chlorosilicon composite material prepared in Example 4, and 15 parts of the fine aggregate coated with chlorosilicon composite material prepared in Example 4 are added to the asphalt for shear stirring and fully mixed evenly to obtain composite modified asphalt concrete. The speed of shear stirring is 2500 r / min, the time of shear stirring is 1 h, and the temperature of shear stirring is 140 °C.

[0086] Example 11

[0087] This example provides a preparation method of composite modified asphalt concrete, including the following steps:

[0088] By weight, 5 parts of 90# asphalt are heated at 138 °C until it becomes completely fluid, and then 2 parts of the modified bamboo fiber prepared in Example 8, 75 parts of the coarse aggregate coated with the chlorosilicon composite material prepared in Example 5, and 25 parts of the fine aggregate coated with the chlorosilicon composite material prepared in Example 5 are added to the asphalt for shear stirring and thoroughly mixed to obtain the composite modified asphalt concrete. The speed of shear stirring is 2600 r / min, the time of shear stirring is 1.5 h, and the temperature of shear stirring is 142 °C.

[0089] Example 12

[0090] This example provides a preparation method of composite modified asphalt concrete, which includes the following steps:

[0091] By weight, 6 parts of 90# asphalt are heated at 140 °C until it becomes completely fluid, and then 5 parts of the modified bamboo fiber prepared in Example 9, 80 parts of the coarse aggregate coated with the chlorosilicon composite material prepared in Example 6, and 30 parts of the fine aggregate coated with the chlorosilicon composite material prepared in Example 6 are added to the asphalt for shear stirring and thoroughly mixed to obtain the composite modified asphalt concrete. The speed of shear stirring is 3000 r / min, the time of shear stirring is 2 h, and the temperature of shear stirring is 145 °C.

[0092] Comparative Example 1

[0093] The difference between this comparative example and Example 12 is that the added coarse aggregate is not coated with the chlorosilicon composite material.

[0094] Comparative Example 2

[0095] The difference between this comparative example and Example 12 is that when preparing the chlorosilicon composite material in Example 3, steps 2 and 3 are cancelled, and trimethoxysilane / polystyrene is used as the coating material.

[0096] Comparative Example 3

[0097] The difference between this comparative example and Example 12 is that bamboo fiber is used to replace the modified bamboo fiber.

[0098] Performance test:

[0099] 1. According to the "Test Regulations for Highway Engineering Aggregates" (JTGE - 2005), the water absorption rate of the composite modified asphalt mixture prepared in Examples 10 - 12 is detected.

[0100] 2. According to the "Test Regulations for Highway Engineering Aggregates" (JCJJ / T190), the permeability coefficient of the composite modified asphalt mixture prepared in Examples 10 - 12 is detected.

[0101] 3. According to the "Test Regulations for Asphalt and Asphalt Mixtures in Highway Engineering", the rutting test was carried out on the composite modified asphalt mixtures prepared in Examples 10-12, and the dynamic stability values were measured.

[0102] 4. The trabecular low-temperature bending test was used to measure the failure stiffness modulus values of the composite modified asphalt mixtures prepared in Examples 10-12.

[0103] The test results are shown in Table 1:

[0104] Table 1

[0105]

[0106] Data analysis:

[0107] In the composite modified asphalt concrete prepared in Examples 10-12 of the present invention, both the coarse aggregate and the fine aggregate are wrapped with a chlorosilicon composite material, and a thin film is formed on the surfaces of the coarse aggregate and the fine aggregate, so that the water absorption rates of the prepared composite modified asphalt concrete all decrease.

[0108] However, compared with inorganic materials, the organic thin film material has good permeability and does not reduce its own permeability coefficient, so it will not affect the drainage capacity of the prepared composite modified asphalt concrete, which is manifested as that the composite modified asphalt concrete prepared in Examples 10-12 all have good permeability coefficients.

[0109] The composite modified asphalt concrete prepared in Examples 10-12 of the present invention all have good high and low temperature resistance, specifically manifested as having better dynamic stability values and failure stiffness modulus values. However, in Comparative Example 1, the coarse aggregate was not coated with a chlorosilicon composite material, and in Comparative Example 2, the coarse aggregate was coated with polystyrene capped with vinyltrimethoxysilane, both of which will reduce the high and low temperature resistance of the prepared composite modified asphalt concrete, specifically manifested as the decrease of the dynamic stability values and the failure stiffness modulus values. And in Comparative Example 3, the bamboo fiber was not modified, which will also reduce the high and low temperature resistance of the prepared composite modified asphalt concrete.

[0110] The above content is only an example and illustration of the structure of the present invention. Those skilled in the art of the present technology make various modifications or supplements to the described specific embodiments or use similar methods to replace them. As long as they do not deviate from the structure of the invention or exceed the scope defined by this claims, they should all fall within the protection scope of the present invention.

[0111] In the description of this specification, the descriptions referring to the terms "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples.

[0112] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the present invention to only the specific implementation manners. Obviously, according to the content of this specification, many modifications and changes can be made. These embodiments are selected and specifically described in this specification in order to better explain the principles and practical applications of the present invention, so that those skilled in the relevant technical field can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A composite modified asphalt concrete, characterized in that: The invention comprises the following components in parts by weight: 4-6 parts of 90# asphalt, 1-5 parts of modified bamboo fiber, 70-80 parts of coarse aggregate coated with chlorosilicon composite material, and 15-30 parts of fine aggregate coated with chlorosilicon composite material; The chlorosilicon composite material is prepared by the following steps: S1, polystyrene, dibenzoyl peroxide and toluene are mixed and stirred, and the temperature is raised to 60-70° C. under a nitrogen atmosphere, and then 15-20 mL of ethylene trimethoxysilane is added dropwise. After the addition is completed, the mixture is activated at this temperature for 30-60 minutes to obtain a reaction system; the reaction system is then distilled under reduced pressure to prepare a trimethoxysilane / polystyrene solid; S2, trimethoxysilane / polystyrene, phosphorus trichloride and acetone are mixed evenly, and then aluminum chloride is added, the temperature is raised to 30-40°C, mixed and reacted at 100r / min for 2-3h, and then the temperature is raised to 80-85°C, and reacted for 2h to obtain a solid; the solid is washed three times with deionized water to obtain a modified organosilicon material; S3, mixing 3,3',3''-trihydroxytriphenoxysilane and modified organic silicon material, heating to 120-140° C., reacting for 1-2 hours, to obtain a solid chlorosilicon composite material; The preparation method of the modified bamboo fiber comprises the following steps: B1. Mix bamboo fiber and 1%wt NaOH solution, soak at room temperature for 1-2h, and then filter to obtain alkalized bamboo fiber; wash the alkalized bamboo fiber three times with deionized water, dry at 70-80°C for 2-3h to obtain dried bamboo fiber; grind the dried bamboo fiber to obtain bamboo fiber powder with a particle size of 300 mesh, 400 mesh or 500 mesh; B2. Mix 2-methyl-4-chloropropionic acid and ethanol to obtain a 2-methyl-4-chloropropionic acid solution; then add bamboo fiber powder to the 2-methyl-4-chloropropionic acid solution, mix and stir to obtain a mixed solid-liquid; then add polytrifluorochloroethylene to the mixed solid-liquid, react at 70-80° C. for 1-2 hours, and obtain modified bamboo fiber.

2. The composite modified asphalt concrete according to claim 1, characterized in that: In step S1, the usage ratio of polystyrene, dibenzoyl peroxide, toluene and ethylene trimethoxysilane is 10-20 g: 0.1 g: 200 mL: 15-20 mL; the pressure of the vacuum distillation is 100 Pa, and the temperature of the vacuum distillation is 110-120° C.

3. The composite modified asphalt concrete according to claim 1, characterized in that: In step S2, the usage ratio of trimethoxysilane / polystyrene, phosphorus trichloride, acetone and aluminum chloride is 30-40g:10-13g:200mL:0.1g; in step S3, the usage ratio of 3,3',3''-trihydroxytriphenoxysilane and modified silicone material is 15-20g:40-50g.

4. The composite modified asphalt concrete according to claim 1, characterized in that: The coarse aggregate coated with the chlorosilicone composite material is prepared by the following steps: A1. Crushing, grinding and sieving basalt to obtain primary coarse aggregate particles with a particle size of 10-15 mm and secondary coarse aggregate particles with a particle size of 5-10 mm; mixing 10 parts of the primary coarse aggregate particles and 10 parts of the secondary coarse aggregate particles uniformly by weight to obtain coarse aggregate; A2. According to parts by weight, 5 parts of coarse aggregate and 100-110 parts of chlorosilicone composite material are mixed evenly, and then dried at 150-160° C. for 3-4 hours to obtain coarse aggregate coated with chlorosilicone composite material.

5. The composite modified asphalt concrete according to claim 1, characterized in that: The fine aggregate coated with the chlorosilicone composite material is prepared by the following steps: The silicon powder is ground and sieved to obtain fine aggregate with a particle size of 1-3 mm; 3 parts of fine aggregate with a particle size of 1-3 mm and 100-110 parts of chlorosilicon composite material are mixed by weight, and then dried at 150-160° C. for 3-4 hours to obtain fine aggregate coated with chlorosilicon composite material.

6. The composite modified asphalt concrete according to claim 5, characterized in that: In step B1, the usage ratio of bamboo fiber and NaOH solution is 10g:100mL; in step B2, the usage ratio of 2-methyl-4-chloropropionic acid and ethanol is 20-30g:50mL, and the usage of polytrifluorochloroethylene is 10g.

7. A method for preparing a composite modified asphalt concrete according to any one of claims 1 to 6, characterized in that: The preparation method of the composite modified asphalt concrete is as follows: heating 90# asphalt at 135-140° C. until it is in a completely fluid state, then adding modified bamboo fiber, coarse aggregate coated with chlorosilicon composite material, and fine aggregate coated with chlorosilicon composite material to the 90# asphalt, shearing and stirring, and mixing evenly to obtain the composite modified asphalt concrete.

8. The method for preparing a composite modified asphalt concrete according to claim 7, characterized in that: The shear stirring speed is 2500-3000 r / min, the shear stirring time is 1-2 h, and the shear stirring temperature is 140-145° C.

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