High-performance composite modified asphalt material and preparation method thereof

Abstract

The invention relates to the field of road technology materials, in particular to a high-performance composite modified asphalt material and a preparation method thereof.The preparation method comprises the steps that S1, anhydrous toluene serves as a solvent, hydroxylated boron nitride and a coupling agent react for 4-6 h under the preset condition, an ethylenediamine solution is added to react for 3-5 h under the preset condition, and drying is conducted after vacuum filtration to obtain modified asphalt; modified boron nitride is obtained; s2, waste rubber is subjected to pretreatment and desulfurization treatment, desulfurized rubber is obtained, the modified boron nitride reacts with the desulfurized rubber, a mechanical ball milling method is adopted for treatment, and modified boron nitride grafted rubber powder is prepared; s3, taking petroleum heavy traffic asphalt 70 #, heating to 160-170 DEG C, shearing at a low speed, adding the modified boron nitride grafted rubber powder and the modified boron nitride at 170-200 DEG C, shearing at a high speed, and stirring in an oil bath at 170-200 DEG C to react for preset time, so as to obtain the high-performance composite modified asphalt material. Compared with the prior art, the soaking residual stability of the asphalt mixture of the high-performance composite modified material is greater than 93%, and the freeze-thaw splitting strength ratio is greater than 89%.

Description

Technical Field

[0001] The present invention relates to the field of road technical materials, and in particular to a high-performance composite modified asphalt material and a preparation method thereof. Background Art

[0002] Compared to cement pavements, asphalt pavements offer advantages such as smoothness, low dust levels, vibration and noise reduction, superior deformation resistance, and easy segmented maintenance. However, conventional asphalt still suffers from poor high- and low-temperature performance, as well as low adhesion, which reduces the pavement's load-bearing capacity and service life. With the increasing popularity of automobiles, increased road traffic volume and vehicle axle loads have increased, increasing road traffic loads. Conventional base asphalt is insufficient to meet the demands of road pavement construction under these increased traffic loads. Therefore, improvements to conventional asphalt are needed to produce a pavement material that meets these transportation construction requirements.

[0003] Currently, polymer materials are used as modifiers for road asphalt. Modified asphalt is obtained by performing single-penetration modification on base asphalt. The high and low temperature performance of the modified asphalt is significantly improved, and the road performance is improved. However, due to the poor compatibility between the asphalt and the modifier, phase separation or deterioration occurs when damaged by low temperature and water. The asphalt mixture made from the modified asphalt has poor performance retention in low temperature and humid environments, poor water immersion residual stability and low-temperature crack resistance, and reduced road load-bearing capacity.

[0004] In order to solve the limitations of the single permeability of asphalt modifiers in improving the road performance of base asphalt, and to improve the poor compatibility between asphalt and modifiers, which leads to poor performance retention of asphalt mixtures in low temperature and humid environments, poor water immersion residual stability and low-temperature crack resistance, the method of the present invention improves the interfacial compatibility between the modifier and the base asphalt to obtain a high-performance composite modified asphalt material, thereby improving the water immersion residual stability and low-temperature crack resistance of the asphalt mixture. Summary of the Invention

[0005] The purpose of the present invention is to provide a high-performance composite modified asphalt material and a preparation method thereof, aiming to solve the limitations of the single permeability of asphalt modifiers in improving the road performance of base asphalt, and to improve the poor compatibility between asphalt and modifiers, which leads to poor water immersion residual stability and low-temperature crack resistance of asphalt mixtures.

[0006] To achieve the above object, the present invention provides a method for preparing a high-performance composite modified asphalt material, the preparation method comprising the following steps:

[0007] S1, using anhydrous toluene as a solvent, reacting hydroxylated boron nitride with a coupling agent under preset conditions for 4-6 hours, adding an ethylenediamine solution and reacting under preset conditions for 3-5 hours, vacuum filtering and drying to obtain modified boron nitride;

[0008] S2, pre-treating and desulfurizing the waste rubber to obtain desulfurized rubber, mixing the modified boron nitride with the desulfurized rubber, and then subjecting the mixture to mechanical ball milling to prepare modified boron nitride grafted rubber powder;

[0009] S3, take petroleum heavy traffic asphalt 70# and heat it to 160-170℃, shear it at low speed, add modified boron nitride grafted rubber powder and modified boron nitride at 170-200℃ and shear it at high speed, stir and react in an oil bath at 170-200℃ for a preset time to obtain a high-performance composite modified asphalt material.

[0010] Preferably, in the above technical solution, in step S1, using anhydrous toluene as a solvent, the hydroxylated boron nitride and the coupling agent are reacted under preset conditions for 4-6 hours, an ethylenediamine solution is added and reacted under preset conditions for 3-5 hours, and the mixture is vacuum filtered and dried to obtain the modified boron nitride, specifically as follows:

[0011] S11, reflux boron nitride in a strong acid at 60-70°C for 6-7 hours, vacuum filter, and dry to obtain hydroxylated boron nitride;

[0012] S12, nitrogen is filled into a three-necked flask containing anhydrous toluene, and hydroxylated boron nitride is added in batches and stirred evenly. After the temperature of the three-necked flask is raised to 75-85°C, a coupling agent is slowly added and the reaction is carried out at a constant temperature for 4.5-5.5 hours. The temperature is raised to 90-100°C and ethylenediamine solution is slowly added and the reaction is carried out at a constant temperature for 3.5-4.5 hours. After vacuum filtration, the modified boron nitride is obtained.

[0013] Preferably, in the above technical solution, in step S12, the coupling agent is a titanate coupling agent.

[0014] Preferably, in the above technical solution, the titanate coupling agent is isopropoxy tris(ethylenediamino-N-ethoxy)peptide ester.

[0015] Preferably, in the above technical solution, the ratio of boron nitride to strong acid is 2-4:1.

[0016] Preferably, in the above technical solution, in step S12, a three-necked flask containing anhydrous toluene is filled with nitrogen at a flow rate of 10-15 L / min for 10-20 minutes, and the hydroxylated boron nitride is added in batches at a speed of 700-900 rpm and stirred evenly. The speed is adjusted to 300-500 rpm and the three-necked flask is heated to 75-85 ° C. After that, isopropoxy tris (ethylenediamino-N-ethoxy) peptide ester is slowly added, and the reaction is carried out at a constant temperature for 4.5-5.5 hours. The temperature is raised to 90-100 ° C. and the ethylenediamine solution is slowly added and the reaction is carried out at a constant temperature for 3.5-4.5 hours. After vacuum filtration, it is placed at 60-70 ° C. and dried for 5-6 hours to obtain modified boron nitride.

[0017] The principle of obtaining modified boron nitride with good interfacial compatibility according to the above technical solution is as follows: (1) using the strong oxidizing property of strong acid to form defect sites on the surface of boron nitride and introduce hydroxyl groups, which are reaction sites for reacting with titanate coupling agents; (2) using isopropoxy tris(ethylenediamine-N-ethoxy) peptide ester to form a defect site on the surface of boron nitride and introduce hydroxyl groups, which are reaction sites for reacting with titanate coupling agents;

[0018] (purchased from Nanjing Nengde New Material Technology Co., Ltd.) and ethylenediamine (purchased from Maoming Chuizi New Material Co., Ltd.) were used to treat hydroxylated boron nitride in two steps. First, isopropoxy tris(ethylenediamine-N-ethoxy) peptide ester activated hydroxylated boron nitride to form a Ti-O-BN covalent bond and provide some free amino groups. Then, ethylenediamine was added to further coordinate or replace the grafted group to the titanium center, and amino-containing groups were grafted on the surface of boron nitride. The amino groups formed hydrogen bonds with the polar groups in the matrix asphalt or rubber, thereby enhancing the interfacial stress transfer of the modified asphalt.

[0019] Furthermore, in step S11, the hydroxylated boron nitride is dried, and in step S12, anhydrous toluene is used as a solvent. Further, before adding the hydroxylated boron nitride, nitrogen is introduced into the reaction vessel to remove air, thereby creating an anhydrous reaction environment, avoiding side reactions between the reactants and water, and improving the purity of the obtained modified boron nitride.

[0020] Preferably, in the above technical solution, in step S2, the waste rubber is pretreated and desulfurized to obtain desulfurized rubber, the modified boron nitride is mixed with the desulfurized rubber, and then mechanically ball milled to produce the modified boron nitride grafted rubber powder, and the specific method is as follows:

[0021] S21, pretreatment: removing metal and other impurities from waste rubber tires, and cutting the waste tire rubber into 50-100mm rubber blocks;

[0022] S22, desulfurization treatment: under inert gas protection and vacuum conditions, the rubber block is heated to 180°C for 3 hours, and then cooled to obtain the desulfurized rubber;

[0023] S23, modified boron nitride grafted rubber powder: take the desulfurized rubber, modified boron nitride, and dimethyl chloromalonate in a preset ratio and add them to an open mill and mix them evenly. Then add sulfur powder and pressurize and react for 10-15 minutes. Use mechanical ball milling to prepare the modified boron nitride grafted rubber powder.

[0024] According to the above technical solution, the tensile strength of the modified boron nitride grafted rubber powder is improved. The principle is as follows: first, sulfur is removed to reduce the interference of the original sulfur on the subsequent vulcanization reaction; second, dimethyl chloromalonate is used as a bridging agent and sulfur powder to promote the formation of chemical bonds between the modified boron nitride and the rubber to achieve grafting, improve the affinity of the rubber, and thus enhance the interfacial compatibility between the rubber and the matrix asphalt.

[0025] Preferably, in the above technical solution, the desulfurized rubber, modified boron nitride and dimethyl chloromalonate are added to an open mill at a ratio of 100:5-15:1-2 and mixed evenly.

[0026] Preferably, in the above technical solution, the pressurized reaction parameters are set as follows: reaction pressure is 2-3 MPa, and reaction temperature is 150-160°C.

[0027] Preferably, in the above technical solution, the process parameters of the mechanical ball milling method are a ball-to-material ratio of 15-20:1, an oscillation frequency of 20-30 Hz, and a ball milling time of 5-6 h.

[0028] A high-performance composite modified asphalt material is prepared by the above-mentioned method for preparing the high-performance composite modified material.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The preparation method of the present invention obtains a high-performance composite modified material with better water immersion residual stability and freeze-thaw splitting strength ratio. The principle is: first, boron nitride is modified to improve the reactivity of boron nitride and improve its interfacial compatibility with rubber and asphalt; second, modified boron nitride is grafted onto rubber powder to improve the interfacial compatibility between rubber and asphalt, and high-performance composite modified asphalt is prepared in synergistic manner with modified boron nitride, thereby enhancing the performance retention ability of asphalt mixture in low temperature and humid environments, and improving its water immersion residual stability and low-temperature crack resistance; finally, the matrix asphalt, rubber grafted with modified boron nitride, and modified boron nitride are mixed and modified to form a ternary continuous phase of rubber-modified boron nitride-asphalt modified boron nitride, thereby enhancing interfacial stress transfer, avoiding local deformation caused by poor stress transfer between components when local pressure is applied, and at the same time improving the bearing capacity of the pavement. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0032] Example 1

[0033] A method for preparing a high-performance composite modified asphalt material, the method comprising:

[0034] S1, the steps for preparing modified boron nitride are as follows:

[0035] S11, reflux boron nitride in concentrated sulfuric acid at 60°C for 6 h, with the ratio of boron nitride to concentrated sulfuric acid being 3:1, vacuum filter and dry at 60°C for 6 h to obtain hydroxylated boron nitride;

[0036] S12, a three-necked flask containing 20 L of anhydrous toluene was charged with nitrogen at a flow rate of 10 L / min for 20 min, 500 g of hydroxylated boron nitride was added in batches with stirring at a speed of 800 rpm, and stirred evenly. The speed was adjusted to 400 rpm and the three-necked flask was heated to 80° C., and then a titanate coupling agent (isopropoxy tris(ethylenediamine-N-ethoxy) peptide ester) was slowly added. The reaction was carried out at a constant temperature for 5 h, and the temperature was raised to 95° C. The ethylenediamine solution was slowly added and the reaction was carried out at a constant temperature for 4 hours. After vacuum filtration, the solution was dried at 60° C. for 6 h to obtain modified boron nitride, wherein the ethylenediamine solution is prepared by uniformly mixing 5 L of anhydrous toluene and 600 mL of ethylenediamine with each other;

[0037] S2, using the modified boron nitride to obtain a modified boron nitride grafted rubber, the specific steps are as follows:

[0038] S21, pretreatment: removing metal and other impurities from waste rubber tires, and cutting the waste tire rubber into 50-100mm rubber blocks;

[0039] S22, desulfurization treatment: under inert gas protection and vacuum conditions, the rubber block is heated to 180°C for 3 hours, and then cooled to obtain the desulfurized rubber;

[0040] S23, modified boron nitride grafted rubber powder: take the desulfurized rubber, modified boron nitride, and dimethyl chloromalonate in a ratio of 50:5:1, add them to an open mill and mix them evenly, add sulfur powder, and react at a temperature of 160° C. and a pressure of 3 MPa for 15 minutes, and use a mechanical ball milling method to prepare the modified boron nitride grafted rubber powder, wherein the process parameters of the mechanical ball milling method are a ball-to-material ratio of 15:1, an oscillation frequency of 25 Hz, and a ball milling time of 6 hours;

[0041] S3: Take petroleum heavy traffic asphalt 70# and heat it to 170℃, shear it at 900 rpm, add modified boron nitride grafted rubber powder and modified boron nitride at 180℃, shear it at 3000 rpm for 30 minutes, stir it in an oil bath at 180℃ at 60 rpm for 2 hours to obtain a high-performance composite modified asphalt material.

[0042] A high-performance composite modified asphalt material is prepared by the above method, wherein the raw materials of the high-performance composite modified asphalt material are composed of modified boron nitride, modified boron nitride grafted rubber powder and petroleum heavy traffic asphalt 70#.

[0043] Example 2

[0044] A method for preparing a high-performance composite modified asphalt material, the method comprising:

[0045] S1, the steps for preparing modified boron nitride are as follows:

[0046] S11, reflux boron nitride in concentrated sulfuric acid at 60°C for 6 h, with the ratio of boron nitride to concentrated sulfuric acid being 3:1, vacuum filter and dry at 70°C for 4 h to obtain hydroxylated boron nitride;

[0047] S12, a three-necked flask containing 10 L of anhydrous toluene was charged with nitrogen at a flow rate of 10 L / min for 10 min, 250 g of hydroxylated boron nitride was added in batches with stirring at a speed of 700 rpm, and stirred evenly. The speed was adjusted to 500 rpm and the three-necked flask was heated to 80° C., and then a titanate coupling agent (isopropoxy tris(ethylenediamino-N-ethoxy) peptide ester) was slowly added. The reaction was carried out at a constant temperature for 5 h, and the temperature was raised to 90° C. The ethylenediamine solution was slowly added and the reaction was carried out at a constant temperature for 4 hours. After vacuum filtration, the solution was dried at 70° C. for 4 h to obtain modified boron nitride, wherein the ethylenediamine solution is prepared by uniformly mixing 2 L of anhydrous toluene and 300 mL of ethylenediamine with anhydrous toluene as a solvent;

[0048] S2, using the modified boron nitride to obtain a modified boron nitride grafted rubber, the specific steps are as follows:

[0049] S21, pretreatment: removing metal and other impurities from waste rubber tires, and cutting the waste tire rubber into 50-100mm rubber blocks;

[0050] S22, desulfurization treatment: under inert gas protection and vacuum conditions, the rubber block is heated to 180°C for 3 hours, and then cooled to obtain the desulfurized rubber;

[0051] S23, modified boron nitride grafted rubber powder: take the desulfurized rubber, modified boron nitride, and dimethyl chloromalonate in a ratio of 50:4:1, add them to an open mill and mix them evenly, add sulfur powder, and react at a temperature of 160° C. and a pressure of 3 MPa for 12 minutes, and use a mechanical ball milling method to prepare the modified boron nitride grafted rubber powder, wherein the process parameters of the mechanical ball milling method are a ball-to-material ratio of 20:1, an oscillation frequency of 30 Hz, and a ball milling time of 5 hours;

[0052] S3: Take petroleum heavy traffic asphalt 70# and heat it to 170℃, shear it at 800 rpm, add modified boron nitride grafted rubber powder and modified boron nitride at 180℃, shear it at 2500 rpm for 30 minutes, stir it in an oil bath at 180℃ at 60 rpm for 2 hours to obtain a high-performance composite modified asphalt material.

[0053] Example 3

[0054] A method for preparing a high-performance composite modified asphalt material, the method comprising:

[0055] S1, the steps for preparing modified boron nitride are as follows:

[0056] S11, reflux boron nitride in concentrated sulfuric acid at 60°C for 6 h, with the ratio of boron nitride to concentrated sulfuric acid being 3:1, vacuum filter and dry at 70°C for 5 h to obtain hydroxylated boron nitride;

[0057] S12, a three-necked flask containing 10 L of anhydrous toluene was charged with nitrogen at a flow rate of 10 L / min for 10 min, 250 g of hydroxylated boron nitride was added in batches with stirring at a speed of 800 rpm, and stirred evenly. The speed was adjusted to 500 rpm and the three-necked flask was heated to 85° C., and then a titanate coupling agent (isopropoxy tris(ethylenediamine-N-ethoxy) peptide ester) was slowly added. The reaction was carried out at a constant temperature for 5 h, and the temperature was raised to 95° C. The ethylenediamine solution was slowly added and the reaction was carried out at a constant temperature for 5 hours. After vacuum filtration, the solution was dried at 70° C. for 5 h to obtain modified boron nitride, wherein the ethylenediamine solution is prepared by uniformly mixing 2 L of anhydrous toluene and 300 mL of ethylenediamine with anhydrous toluene as a solvent;

[0058] S2, using the modified boron nitride to obtain a modified boron nitride grafted rubber, the specific steps are as follows:

[0059] S21, pretreatment: removing metal and other impurities from waste rubber tires, and cutting the waste tire rubber into 50-100mm rubber blocks;

[0060] S22, desulfurization treatment: under inert gas protection and vacuum conditions, the rubber block is heated to 180°C for 3 hours, and then cooled to obtain the desulfurized rubber;

[0061] S23, modified boron nitride grafted rubber powder: take the desulfurized rubber, modified boron nitride, and dimethyl chloromalonate in a ratio of 100:5-15:1-2, add them to an open mill and mix them evenly, add sulfur powder, and react at a temperature of 160° C. and a pressure of 3 MPa for 15 minutes, and use a mechanical ball milling method to prepare the modified boron nitride grafted rubber powder, wherein the process parameters of the mechanical ball milling method are a ball-to-material ratio of 20:1, an oscillation frequency of 30 Hz, and a ball milling time of 5 hours;

[0062] S3: Take petroleum heavy traffic asphalt 70# and heat it to 170℃, shear it at 900 rpm, add modified boron nitride grafted rubber powder and modified boron nitride at 180℃, shear it at 3000 rpm for 30min, stir it in an oil bath at 180℃ at 60 rpm for 2h, and obtain a high-performance composite modified asphalt material.

[0063] Comparative Example 1

[0064] A method for preparing a waste rubber modified asphalt material, the method comprising:

[0065] S1, preparing desulfurized rubber powder using waste rubber, the specific steps are as follows:

[0066] S11, pretreatment: removing metal and other impurities from waste rubber tires, and cutting the waste tire rubber into 50-100mm rubber blocks;

[0067] S12, desulfurization treatment: under inert gas protection and vacuum conditions, the rubber block is heated to 180° C. for 3 hours, cooled, and mechanically milled to obtain desulfurized rubber powder, wherein the process parameters of the mechanical ball milling method are a ball-to-material ratio of 15:1, an oscillation frequency of 25 Hz, and a ball milling time of 6 hours;

[0068] S2, take petroleum heavy traffic asphalt 70#, heat it to 170℃, shear it at 900 rpm, add desulfurized rubber powder and boron nitride at 180℃, shear it at 3000 rpm for 30min, stir it in an oil bath at 180℃ at 60 rpm for 2h, and obtain a composite modified asphalt material.

[0069] Comparative Example 2

[0070] A method for preparing a nano-boron nitride modified asphalt material, the method comprising:

[0071] S1, preparing desulfurized rubber powder using waste rubber, the specific steps are as follows:

[0072] S11, pretreatment: removing metal and other impurities from waste rubber tires, and cutting the waste tire rubber into 50-100mm rubber blocks;

[0073] S12, desulfurization treatment: under inert gas protection and vacuum conditions, the rubber block is heated to 180° C. for 3 hours, cooled, and mechanically milled to obtain desulfurized rubber powder, wherein the process parameters of the mechanical ball milling method are a ball-to-material ratio of 15:1, an oscillation frequency of 25 Hz, and a ball milling time of 6 hours;

[0074] S2: Take petroleum heavy traffic asphalt 70# and heat it to 170℃, shear it at 900 rpm, add desulfurized rubber powder at 180℃, shear it at 3000 rpm for 30min, stir it in an oil bath at 180℃ at 60 rpm for 2h to obtain rubber-modified asphalt material.

[0075] Comparative Example 3

[0076] A method for preparing a high-performance composite modified asphalt material, the method comprising:

[0077] S1, boron nitride was refluxed in concentrated sulfuric acid at 60°C for 6 h, with the ratio of boron nitride to concentrated sulfuric acid being 3:1, vacuum filtered, dried at 60°C for 6 h, and mechanically milled to obtain hydroxylated boron nitride powder. The process parameters of the mechanical ball milling method were a ball-to-material ratio of 20:1, an oscillation frequency of 30 Hz, and a ball milling time of 5 h;

[0078] S2, preparing desulfurized rubber powder using waste rubber, the specific steps are as follows:

[0079] S21, pretreatment: removing metal and other impurities from waste rubber tires, and cutting the waste tire rubber into 50-100mm rubber blocks;

[0080] S22, desulfurization treatment: Under inert gas protection and vacuum conditions, the rubber block is heated to 180° C. for 3 hours, cooled, and mechanically milled to obtain desulfurized rubber powder. The process parameters of the mechanical ball milling method are a ball-to-material ratio of 15:1, an oscillation frequency of 25 Hz, and a ball milling time of 6 hours.

[0081] S3: Take petroleum heavy traffic asphalt 70# and heat it to 170℃, shear it at 900 rpm, add desulfurized rubber powder and hydroxylated boron nitride powder at 180℃, shear it at 3000 rpm for 30min, stir it in an oil bath at 180℃ at 60 rpm for 2h, and obtain a composite modified asphalt material.

[0082] The tests were conducted using an AC-13 asphalt mixture, with the mineral material mix proportions based on the median gradation range specified in the Technical Specification for Highway Asphalt Pavement Construction (JTGF40-2004). The asphalt mixture was subjected to the Marshall immersion test and the Marshall stability test for asphalt mixtures according to T0709-2011. The test results are shown in Table 1. The asphalt mixture freeze-thaw splitting test was conducted according to T0729-2000. The test results are shown in Table 2.

[0083] Table 1 Stability test results of Examples 1-3 and Comparative Examples 1-3

[0084]

[0085] As can be seen from the above table, the water immersion residual stability of the asphalt mixtures of the high-performance composite modified asphalt materials obtained using the method of the present invention in Examples 1, 2 and 3 is significantly better than that of the asphalt mixtures of the asphalt materials obtained by the preparation methods of Comparative Examples 1, 2 and 3; compared with Comparative Example 1, Comparative Example 3 shows that the composite modified asphalt material obtained by adding desulfurized rubber and hydroxylated boron nitride powder to petroleum heavy traffic asphalt has better water immersion resistance than that obtained by adding desulfurized rubber powder and boron nitride.

[0086] Table 2 Cracking test results of Examples 1-3 and Comparative Examples 1-3

[0087]

[0088] As can be seen from the above table, the freeze-thaw splitting strength ratio of the asphalt mixtures of the high-performance composite modified asphalt materials obtained using the method of the present invention in Examples 1, 2 and 3 is significantly better than that of the asphalt mixtures of the asphalt materials obtained using the preparation methods of Comparative Examples 1, 2 and 3; compared with Comparative Example 1, Comparative Example 3 shows that the composite modified asphalt material obtained by adding desulfurized rubber and hydroxylated boron nitride powder to petroleum heavy traffic asphalt has better freeze-thaw crack resistance than that obtained by adding desulfurized rubber powder and boron nitride.

[0089] Comparative Example 4

[0090] A method for preparing a high-performance composite modified asphalt material, the method comprising:

[0091] S1, the steps for preparing modified boron nitride are as follows:

[0092] S11, reflux boron nitride in concentrated sulfuric acid at 60°C for 6 h, with the ratio of boron nitride to concentrated sulfuric acid being 3:1, vacuum filter and dry at 60°C for 6 h to obtain hydroxylated boron nitride;

[0093] S12, a three-necked flask containing 20 L of anhydrous toluene was charged with nitrogen at a flow rate of 10 L / min for 20 min, and 500 g of hydroxylated boron nitride was added in batches with stirring at 800 rpm. The stirring was uniform, and the speed was adjusted to 400 rpm. The three-necked flask was heated to 80°C, and then a titanate coupling agent (isopropoxy tris(ethylenediamino-N-ethoxy) peptide ester) was slowly added. The reaction was kept at a constant temperature for 5 h, and the mixture was vacuum filtered and dried at 60°C for 6 h to obtain modified boron nitride.

[0094] S2, preparing desulfurized rubber powder using waste rubber, the specific steps are as follows:

[0095] S21, pretreatment: removing metal and other impurities from waste rubber tires, and cutting the waste tire rubber into 50-100mm rubber blocks;

[0096] S22, desulfurization treatment: Under inert gas protection and vacuum conditions, the rubber block is heated to 180° C. for 3 hours, cooled, and mechanically milled to obtain desulfurized rubber powder. The process parameters of the mechanical ball milling method are a ball-to-material ratio of 15:1, an oscillation frequency of 25 Hz, and a ball milling time of 6 hours.

[0097] S23, modified boron nitride grafted rubber powder: take the desulfurized rubber, modified boron nitride, and dimethyl chloromalonate in a ratio of 50:5:1, add them to an open mill and mix them evenly, add sulfur powder, and react at a temperature of 160° C. and a pressure of 3 MPa for 15 minutes, and use a mechanical ball milling method to prepare the modified boron nitride grafted rubber powder, wherein the process parameters of the mechanical ball milling method are a ball-to-material ratio of 15:1, an oscillation frequency of 25 Hz, and a ball milling time of 5 hours;

[0098] S3: Take petroleum heavy traffic asphalt 70# and heat it to 170℃, shear it at 900 rpm, add modified boron nitride grafted rubber powder at 180℃, shear it at 3000 rpm for 30 minutes, stir it in an oil bath at 180℃ at 60 rpm for 2 hours to obtain a high-performance composite modified asphalt material.

[0099] Comparative Example 5

[0100] A method for preparing a high-performance composite modified asphalt material, the method comprising:

[0101] S1, taking the modified boron nitride prepared by the modified boron nitride preparation method in Comparative Example 4;

[0102] S2, using the modified boron nitride to obtain a modified boron nitride grafted rubber, the specific steps are as follows:

[0103] S21, pretreatment: removing metal and other impurities from waste rubber tires, and cutting the waste tire rubber into 50-100mm rubber blocks;

[0104] S22, desulfurization treatment: Under inert gas protection and vacuum conditions, the rubber block is heated to 180° C. for 3 hours, cooled, and mechanically milled to obtain desulfurized rubber powder. The process parameters of the mechanical ball milling method are a ball-to-material ratio of 15:1, an oscillation frequency of 25 Hz, and a ball milling time of 6 hours.

[0105] S3, take petroleum heavy traffic asphalt 70#, heat it to 170℃, shear it at 900 rpm, add desulfurized rubber powder and modified boron nitride at 180℃, shear it at 3000 rpm for 30 minutes, stir it in an oil bath at 180℃ at 60 rpm for 2 hours, and obtain a high-performance composite modified asphalt material.

[0106] Comparative Example 6

[0107] A method for preparing a high-performance composite modified asphalt material, the method comprising:

[0108] S1, modified boron nitride prepared by the modified boron nitride preparation method in Example 1;

[0109] S2, using the modified boron nitride to obtain a modified boron nitride grafted rubber, the specific steps are as follows:

[0110] S21, pretreatment: removing metal and other impurities from waste rubber tires, and cutting the waste tire rubber into 50-100mm rubber blocks;

[0111] S22, desulfurization treatment: Under inert gas protection and vacuum conditions, the rubber block is heated to 180° C. for 3 hours, cooled, and mechanically milled to obtain desulfurized rubber powder. The process parameters of the mechanical ball milling method are a ball-to-material ratio of 15:1, an oscillation frequency of 25 Hz, and a ball milling time of 6 hours.

[0112] S3, take petroleum heavy traffic asphalt 70#, heat it to 170℃, shear it at 900 rpm, add desulfurized rubber powder and modified boron nitride at 180℃, shear it at 3000 rpm for 30 minutes, stir it in an oil bath at 180℃ at 60 rpm for 2 hours, and obtain a high-performance composite modified asphalt material.

[0113] The tests were conducted using an AC-13 asphalt mixture, with the mineral material mix proportions based on the median of the gradation range specified in the Technical Specification for Highway Asphalt Pavement Construction (JTGF40-2004). The asphalt mixture was subjected to the Marshall immersion test and the Marshall stability test for asphalt mixtures according to T0709-2011. The test results are shown in Table 3. The asphalt mixture freeze-thaw splitting test was conducted according to T0729-2000. The test results are shown in Table 4.

[0114] Table 3 Stability test results of Examples 1-3 and Comparative Examples 4-5

[0115]

[0116] It can be seen from the above table that the asphalt mixtures of the high-performance composite modified asphalt materials obtained by the method of Examples 1-3 using the present invention are more stable than the asphalt mixtures of the asphalt materials obtained by the preparation methods of Comparative Examples 4-6. Although isopropoxy tris(ethylenediamino-N-ethoxy) peptide ester contains amino groups, the addition of ethylenediamine to treat boron nitride enhances the water immersion residual stability of the asphalt mixture to a certain extent, making its water immersion stability greater than 93%.

[0117] Table 4 Cracking test results of Examples 1-3 and Comparative Examples 4-5

[0118]

[0119]

[0120] As can be seen from the above table, the freeze-thaw splitting strength ratio (TSR) of the asphalt mixture of the high-performance composite asphalt material prepared by the method of the present invention is greater than 89%, which is better than the asphalt mixture obtained by other preparation methods.

[0121] The present invention can be implemented in various ways and is not limited to the embodiments described above. A person skilled in the art will appreciate that the present invention can be implemented in other specific ways without changing the technical concept or essential features of the present invention. Therefore, it should be understood that the embodiments described above are illustrative and not intended to limit the present invention.

Claims

1. A method for preparing a high-performance composite modified asphalt material, characterized in that: The preparation method comprises: S1, using anhydrous toluene as a solvent, reacting hydroxylated boron nitride with a coupling agent under preset conditions for 4-6 hours, adding an ethylenediamine solution and reacting under preset conditions for 3-5 hours, vacuum filtering and drying to obtain modified boron nitride; S2, pre-treating and desulfurizing the waste rubber to obtain desulfurized rubber, reacting the modified boron nitride with the desulfurized rubber, and then subjecting the reactants to mechanical ball milling to produce modified boron nitride grafted rubber powder; S3, take petroleum heavy traffic asphalt 70# and heat it to 160-170℃, shear it at low speed, add modified boron nitride grafted rubber powder and modified boron nitride at 170-200℃ and shear it at high speed, stir and react in an oil bath at 170-200℃ for a preset time to obtain a high-performance composite modified asphalt material.

2. The method for preparing a high-performance composite modified asphalt material according to claim 1, wherein: In step S1, using anhydrous toluene as a solvent, hydroxylated boron nitride and a coupling agent are reacted under preset conditions for 4-6 hours, an ethylenediamine solution is added and reacted under preset conditions for 3-5 hours, and the mixture is vacuum filtered and dried to obtain the modified boron nitride, specifically as follows: S11, reflux boron nitride in a strong acid at 60-70°C for 6-7 hours, vacuum filter, and dry to obtain hydroxylated boron nitride; S12, nitrogen is filled into a three-necked flask containing anhydrous toluene, and hydroxylated boron nitride is added in batches and stirred evenly. After the temperature of the three-necked flask is raised to 75-85°C, a coupling agent is slowly added and the reaction is carried out at a constant temperature for 4.5-5.5 hours. The temperature is raised to 90-100°C and ethylenediamine solution is slowly added and the reaction is carried out at a constant temperature for 3.5-4.5 hours. After vacuum filtration, the modified boron nitride is obtained.

3. The method for preparing a high-performance composite modified asphalt material according to claim 2, wherein: In the step S12, the coupling agent is a titanate coupling agent.

4. The method for preparing a high-performance composite modified asphalt material according to claim 3, wherein: The titanate coupling agent is isopropoxy tris(ethylenediamino-N-ethoxy)peptide ester.

5. The method for preparing a high-performance composite modified asphalt material according to claim 4, wherein: The ratio of the boron nitride to the strong acid is 2-4:

1.

6. The method for preparing a high-performance composite modified asphalt material according to claim 1, wherein: In step S2, the waste rubber is pretreated and desulfurized to obtain desulfurized rubber, the modified boron nitride is mixed with the desulfurized rubber, and then mechanically milled to produce modified boron nitride grafted rubber powder. The specific method is as follows: S21, pretreatment: removing metal and other impurities from waste rubber tires, and cutting the waste tire rubber into 50-100mm rubber blocks; S22, desulfurization treatment: Under inert gas protection and vacuum conditions, the rubber block is heated to 180-190°C for 3-5 hours, and then cooled to obtain desulfurized rubber; S23, modified boron nitride grafted rubber powder: take the desulfurized rubber, modified boron nitride, and dimethyl chloromalonate in a preset ratio and add them to an open mill and mix them evenly. Then add sulfur powder and pressurize and react for 10-15 minutes. Use mechanical ball milling to prepare the modified boron nitride grafted rubber powder.

7. The method for preparing a high-performance composite modified asphalt material according to claim 6, wherein: The desulfurized rubber, modified boron nitride and dimethyl chloromalonate are added into an open mill at a ratio of 100:5-15:1-2 and mixed evenly.

8. The method for preparing a high-performance composite modified asphalt material according to claim 6, wherein: The pressurized reaction parameters are set as follows: reaction pressure is 2-3 MPa, and reaction temperature is 150-160°C.

9. The method for preparing a high-performance composite modified asphalt material according to claim 6, wherein: The process parameters of the mechanical ball milling method are a ball-to-material ratio of 15-20:1, an oscillation frequency of 20-30 Hz, and a ball milling time of 5-6 h.

10. A high-performance composite modified asphalt material, characterized in that: The high-performance composite modified asphalt is prepared by the preparation method of the high-performance composite modified asphalt material according to any one of claims 1-9.

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