Composite asphalt material for road and preparation method thereof

Abstract

The invention discloses a composite asphalt material for a road and a preparation method thereof. The composite asphalt material for the road comprises the following components in parts by weight: 60-75 parts of modified asphalt, 18-25 parts of aggregate, 10-15 parts of mineral powder, 10-12 parts of filler modified hollow glass beads and 5-8 parts of binder modified phenolic resin. According to the invention, the matrix asphalt, the filler hollow glass beads and the binder phenolic resin are respectively modified, and the modified asphalt, the modified hollow glass beads and the modified phenolic resin play a synergistic effect with the mineral powder and the aggregate; the prepared road composite asphalt material has good mechanical properties, wear resistance, high-temperature stability, low-temperature crack resistance, aging resistance and fatigue resistance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of asphalt materials, in particular to a road composite asphalt material and a preparation method thereof. BACKGROUND

[0002] With the rapid development of urban construction in China, building highways and bridges has become an important part of the development of China's infrastructure. As a pavement material, it not only needs to have excellent mechanical properties and long service life, but also needs to have good wear resistance, high-temperature stability, low-temperature crack resistance and fatigue resistance. The traditional pavement asphalt has low strength, poor temperature resistance and short fatigue life, which has been unable to meet the needs of road construction. Moreover, after a period of service, the asphalt pavement will appear cracks and aging problems under the action of adverse environments such as ultraviolet light irradiation, extreme low temperature and continuous heavy vehicle load, and the surface layer of the pavement will deform under the action of long-time vehicle load.

[0003] In order to solve the above problems in the prior art, domestic and foreign researchers have carried out a large amount of research on road asphalt materials. For example, a composite modified asphalt and a preparation method thereof are disclosed in Chinese Patent No. CN119242063A, which belongs to the technical field of high polymer materials. The composite modified asphalt contains SBS modified asphalt, modified tire rubber powder, epoxy asphalt, SBR, high modulus anti-rutting agent, asphalt warm mixing agent, malin acid resin, rubber softening oil, ethylhexyl stearate, isopropyl stearate and the like. The SBS modified asphalt is modified by SBS modifier and further added with calcium stearate, isopropyl stearate, asphalt warm mixing agent and the like. The modified tire rubber powder is obtained by surface composite coating modification of waste tire rubber powder as raw material, basalt fiber, silica ash and AH-130 asphalt powder. The composite modified asphalt prepared by melting and blending of various components has good high temperature stability, low temperature crack resistance, fatigue resistance and water damage resistance, and better adapts to the use environment of elevated bridge pavement. However, the wear resistance and aging resistance of the asphalt material provided in the invention are poor, and further improvement is needed. In order to further improve the wear resistance of road asphalt material, Chinese Patent No. CN119081433A discloses a high-temperature-resistant and wear-resistant composite asphalt material, a preparation method and application thereof, which belongs to the technical field of highway pavement materials. The high-temperature-resistant and wear-resistant composite asphalt material comprises the following raw material components in mass percentage: 25-80% of lake asphalt, 3-6% of lignin sulfonate modified asphalt, 5-8% of waste ceramic particles and the balance of oyster shell modified rubber particles. The composition of the high-temperature-resistant and wear-resistant composite asphalt material is simple, the preparation process is simple and the performance is excellent, effectively solving the problems of poor wear resistance and limited service life of asphalt pavement with lake asphalt as the main raw material in the prior art, and providing a more economical and environmental protection technical scheme for highway pavement materials. However, the low temperature crack resistance, aging resistance and fatigue resistance of the composite asphalt material obtained in the invention have not been well improved. Therefore, it is a technical problem to be solved by the current researchers to develop a road asphalt material with good mechanical properties, wear resistance, high temperature stability, low temperature crack resistance and fatigue resistance, so as to prolong the service life of asphalt pavement. SUMMARY

[0004] In order to solve the problems existing in the prior art, the purpose of the present application is to provide a road composite asphalt material and a preparation method thereof. The base asphalt, the filler hollow glass microspheres and the adhesive phenolic resin are modified respectively, and the modified asphalt, the modified hollow glass microspheres and the modified phenolic resin play a synergistic effect with the mineral powder and the aggregate, thereby significantly improving the mechanical properties, wear resistance, high temperature stability, low temperature crack resistance, aging resistance and fatigue resistance of the road composite asphalt material.

[0005] To achieve the above object, the present application adopts the following technical solutions:

[0006] A road composite asphalt material, which comprises the following components in parts by weight: modified asphalt 60-75 parts, aggregate 18-25 parts, mineral powder 10-15 parts, filler modified hollow glass microsphere 10-12 parts and binder modified phenolic resin 5-8 parts.

[0007] Further, the preparation method of the modified asphalt is specifically as follows:

[0008] (1) heat the base asphalt to 180-220℃, keep warm for 2-4h to obtain molten asphalt;

[0009] (2) add the coupling agent γ-aminopropyl triethoxysilane into anhydrous ethanol, stir and mix uniformly, slowly add acetic acid to adjust the pH value of the solution to 4-5, heat and stir the above solution to 30-40℃, react for 20-40min; then add calcium sulfate whiskers, react at 75-80℃ for 40-60min; wash and filter while hot to obtain modified calcium sulfate whiskers;

[0010] (3) place the molten asphalt obtained in step (1) and SBS in a shear machine with a shear speed of 3500-4500rpm, shear and stir for 30-40min, slowly add rare earth compound cerium oxide powder and modified calcium sulfate whiskers at a temperature of 165-170℃, mix uniformly, then mechanically stir at a speed of 3500-4500rpm for 40-60min, after stirring is completed, stand for 1-2h to obtain modified asphalt.

[0011] Further, the mass ratio of the coupling agent γ-aminopropyl triethoxysilane, anhydrous ethanol and calcium sulfate whiskers in step (2) is 1:(26-40):(14-20); the mass ratio of the molten asphalt, SBS, cerium oxide powder and modified calcium sulfate whiskers in step (3) is 1:(0.5-0.8):(0.15-0.25):(0.3-0.4).

[0012] Further, the aggregate is bentonite powder, which is divided according to particle size and comprises continuous gradation with a particle size of 8-12mm, accounting for 50-70% of the total mass of the aggregate; continuous gradation with a particle size of 5-8mm, accounting for 30-50% of the total mass of the aggregate.

[0013] Further, the mineral powder is quicklime powder, which is divided according to particle size and comprises continuous gradation with a particle size of 4-6mm, accounting for 60-80% of the total mass of the mineral powder; continuous gradation with a particle size of 2-4mm, accounting for 20-40% of the total mass of the mineral powder.

[0014] Further, the preparation method of the filler modified hollow glass microsphere is specifically as follows:

[0015] 1) Put the hollow glass microsphere into a beaker, add sodium hydroxide solution, heat and reflux at 75-85 DEG C for 1.5-2.5 h, then wash with clean water until neutral, and dry to obtain pretreated hollow glass microsphere;

[0016] 2) Put the pretreated hollow glass microsphere obtained in step 1) into a flask, add anhydrous ethanol, then add coupling agent γ-aminopropyl triethoxysilane, and react at 80-85 DEG C for 2-4 h, then wash, suction filter and dry to obtain modified hollow glass microsphere.

[0017] Further, the use amount ratio of the hollow glass microsphere to sodium hydroxide solution in step 1) is 1:(0.3-0.4); and the mass ratio of the pretreated hollow glass microsphere to silane coupling agent in step 2) is 1:(0.15-0.2).

[0018] Further, the preparation method of the binder modified phenolic resin is specifically as follows:

[0019] Mix phenol and formaldehyde solution uniformly, under stirring, add sodium hydroxide solution to adjust pH to 7.5-8.5, heat to 75-80 DEG C and react for 60-80 min, then add nano-lignin, react at 85-90 DEG C for 2.5-3 h, then maintain the temperature, add montmorillonite and continue to stir at high speed for 1-1.5 h, and then reduce to room temperature to obtain modified phenolic resin.

[0020] Further, the molar ratio of phenol, formaldehyde and nano-lignin is (0.48-0.6):(1.2-1.8):(0.32-0.4); the mass percentage of formaldehyde in the formaldehyde solution is 35-40%; and the amount of montmorillonite is 4-6% of the total mass of phenol, formaldehyde and nano-lignin.

[0021] Further, a preparation method of the road composite asphalt material is provided, which comprises the following steps:

[0022] Step S1, mix aggregate and mineral powder, preheat at 160-180 DEG C for 3-5 min to obtain preheated mixture;

[0023] Step S2, add modified asphalt into a mixing pot, heat to 170-180 DEG C, mix, then add the preheated mixture obtained in step S1, stir for 2-4 min, then add modified hollow glass microsphere and binder modified phenolic resin, and stir and mix for 6-10 min to obtain the road composite asphalt material.

[0024] Compared with the prior art, the present application has the following positive and beneficial effects:

[0025] (1) The present application utilizes SBS, cerium oxide powder and modified calcium sulfate whisker to compound modify asphalt to obtain modified asphalt. Since SBS has good viscoelasticity, it can help asphalt maintain sufficient flexibility in low temperature environment, thereby reducing the risk of pavement cracking due to temperature change, and the structural support of modified calcium sulfate whisker reduces the internal stress concentration of pavement asphalt material in cold shrinkage process, thereby reducing the formation of cracks. SBS and modified calcium sulfate whisker synergistically improve the low temperature crack resistance and fatigue resistance of the composite asphalt material; cerium oxide is distributed in the three-dimensional grid structure of SBS crosslinking, making the three-dimensional grid structure more compact and firm, thereby improving the anti-aging property and high temperature stability of the composite asphalt material. Meanwhile, cerium oxide plays a bridging role through its surface, making asphalt molecules wrap or adsorb around cerium oxide to form larger particles. The existence of these particles also improves the high temperature stability and wear resistance of the composite asphalt material; and the unique structure of rare earth element cerium can capture free radicals through its numerous empty orbits of atoms and ions, slowing down the generation of oxygen-containing functional groups in the asphalt aging process, thereby delaying the oxidation aging process of asphalt and improving the anti-aging ability of the composite asphalt material; by improving the calcium sulfate whisker, amine groups and ethoxyl groups are introduced into asphalt molecules, which can react with the hydroxyl or carboxyl groups of modified phenolic resin, increasing the bonding force between asphalt material and phenolic resin, thereby improving the mechanical properties of the composite asphalt material. Moreover, the modified calcium carbonate whisker synergistically acts with mineral powder and aggregate to effectively improve the wear resistance, low temperature crack resistance and mechanical properties of the composite asphalt material.

[0026] (2) The present application firstly adopts nanometer lignin to replace part of phenol to react with formaldehyde to obtain lignin modified phenol formaldehyde resin, and then the lignin modified phenol formaldehyde resin is modified by montmorillonite to obtain modified phenol formaldehyde resin; because lignin contains a large number of hydroxyl, carboxyl, aromatic and other groups, a large substituent group is introduced into the lignin modified phenol formaldehyde resin, and gradually cross-linked to form a macromolecular network structure, which makes the lignin modified phenol formaldehyde resin have high thermal stability and mechanical strength, and because montmorillonite has its own characteristics, the addition of montmorillonite can further enhance the high temperature stability of the phenol formaldehyde resin, thereby improving the high temperature stability of the composite asphalt material; the lignin modified phenol formaldehyde resin can form a uniform cross-linked network during the curing process, fill the micro pores and cracks in the composite asphalt material, and improve the mechanical strength of the composite asphalt material; and the montmorillonite has good swelling and filling properties, can form a fine filling layer in the composite asphalt material, further reduce internal defects and stress concentration points, and the lignin and montmorillonite jointly modify the phenol formaldehyde resin, so that the composite asphalt material can uniformly expand and shrink under high and low temperature conditions, reduce the cracking phenomenon caused by uneven stress, thereby improving the high temperature stability, low temperature crack resistance and fatigue resistance of the composite asphalt material. The modified phenol formaldehyde resin contains a variety of active groups such as hydroxyl and carboxyl on the molecular chain, which can chemically react or physically adsorb with the amine groups or other groups on the surface of the modified asphalt and the modified filler glass microspheres to form a firm chemical bond or physical combination, which greatly enhances the interaction and compatibility between the composite asphalt materials, thereby improving the mechanical strength of the composite asphalt material, and at high temperature, the binding force can resist the damage of thermal stress, thereby improving the high temperature stability and fatigue resistance of the composite asphalt material.

[0027] (3) The present application uses silane coupling agent γ-aminopropyl triethoxysilane to modify the surface of hollow glass microspheres, and the nitrogen atoms on the surface of the modified hollow glass microspheres form hydrogen bonds with the hydrogen atoms on the modified asphalt and modified phenol formaldehyde resin, thereby enhancing the interaction between the filler hollow glass microspheres and the modified asphalt and modified phenol formaldehyde resin, and improving the mechanical properties, anti-aging properties and high temperature stability of the composite asphalt material.

[0028] (4) The present application can effectively improve the water stability of the composite asphalt material, improve the high temperature resistance, low temperature crack resistance and fatigue resistance of the composite asphalt material by using lime powder as mineral powder and bentonite powder as aggregate, and the particle size grading of the mineral powder and aggregate can improve the wear resistance and strength of the composite asphalt material; and the synergistic effect of the modified asphalt, filler modified hollow glass microspheres, binder modified phenol formaldehyde resin, mineral powder and aggregate can improve the mechanical properties, wear resistance, high temperature stability, low temperature crack resistance and fatigue resistance of the road composite asphalt material. DETAILED DESCRIPTION

[0029] The technical solutions of the present application are further specifically illustrated by the following examples, which are for the purpose of illustrating the present application and are not a limitation of the present application. Based on the examples in the present application, all other examples obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present application.

[0030] The experimental methods in the examples are all conventional methods unless otherwise specified; the reagents and materials can be obtained from commercial channels unless otherwise specified.

[0031] Example 1

[0032] A road composite asphalt material comprises the following components in parts by weight: modified asphalt 60 parts, aggregate 18 parts, mineral powder 12 parts, filler modified hollow glass microspheres 10 parts, and binder modified phenolic resin 5 parts. Among them, the aggregate is bentonite powder, which is divided according to particle size and includes continuous gradation with a particle size of 8-12 mm, accounting for 70% of the total mass of the aggregate; continuous gradation with a particle size of 5-8 mm, accounting for 30% of the total mass of the aggregate; the mineral powder is quicklime powder, which is divided according to particle size and includes continuous gradation with a particle size of 4-6 mm, accounting for 60% of the total mass of the mineral powder; continuous gradation with a particle size of 2-4 mm, accounting for 40% of the total mass of the mineral powder.

[0033] A preparation method of the above-mentioned road composite asphalt material, comprising the following steps:

[0034] Step S1, mix the aggregate and mineral powder, preheat at 160℃ for 5min to obtain a preheated mixture;

[0035] Step S2, add the modified asphalt into a mixing pot, heat to 170℃, after mixing, add the preheated mixture obtained in step S1, stir for 4min, add modified hollow glass microspheres and binder modified phenolic resin, and stir and mix for 10min to obtain the road composite asphalt material.

[0036] The preparation method of the modified asphalt in this example is as follows:

[0037] (1) Heat the base asphalt to 180℃ and keep for 4h to obtain molten asphalt;

[0038] (2) Stir and mix the coupling agent γ-aminopropyl triethoxysilane in anhydrous ethanol until uniform, slowly add acetic acid to adjust the pH value of the solution to 4-5, heat and stir the above-mentioned solution to 30℃, and react for 40min; then add calcium sulfate whiskers and react at 75℃ for 60min; while hot, wash and filter to obtain modified calcium sulfate whiskers; wherein the mass ratio of γ-aminopropyl triethoxysilane, anhydrous ethanol and calcium sulfate whiskers is 1:26:14;

[0039] (3) the molten pitch obtained in step (1) is placed in a shearing machine with a shearing speed of 3500 rpm for shearing stirring for 40 min, and at a temperature of 165 ℃, a rare earth compound cerium oxide powder and modified calcium sulfate whisker are slowly added and uniformly mixed, and then mechanical stirring is carried out at a speed of 3500 rpm for 60 min, and after stirring is completed, standing for 1 h, to obtain a modified pitch. The mass ratio of the molten pitch, SBS, cerium oxide powder and modified calcium sulfate whisker is 1:0.5:0.15:0.3.

[0040] The preparation method of the filler modified hollow glass microsphere in the embodiment is as follows:

[0041] 1) The hollow glass microspheres are placed in a beaker, and a sodium hydroxide solution is added, and reflux reaction is carried out at 75 ℃ for 2.5 h, and then washed with clean water until neutral, and dried to obtain pretreated hollow glass microspheres; wherein the use amount ratio of the hollow glass microspheres and the sodium hydroxide solution is 1:0.3;

[0042] 2) The pretreated hollow glass microspheres obtained in step 1) are placed in a flask, anhydrous ethanol is added, and then a coupling agent γ-aminopropyl triethoxysilane is added, and reaction is carried out at 80 ℃ for 4 h, and then washed, suction filtered and dried to obtain modified hollow glass microspheres; wherein the mass ratio of the pretreated hollow glass microspheres and the silane coupling agent is 1:0.15.

[0043] The preparation method of the binder modified phenolic resin in the embodiment is as follows:

[0044] The phenol and formaldehyde solution are uniformly mixed, and under stirring conditions, a sodium hydroxide solution is added to adjust the pH to 7.5-8.5, and the temperature is raised to 75 ℃ for reaction for 80 min, and then nano-lignin is added, and reaction is carried out at 85 ℃ for 3 h, and then the temperature is maintained, and montmorillonite is added and continues to be sheared and stirred at high speed for 1.5 h, and then the temperature is lowered to room temperature, to obtain the modified phenolic resin. The molar ratio of the phenol, formaldehyde and nano-lignin is 0.48:1.2:0.32; the mass percentage of formaldehyde in the formaldehyde solution is 35%; and the amount of the montmorillonite is 4% of the total mass of the phenol, formaldehyde and nano-lignin.

[0045] Example 2

[0046] The application discloses a kind of road composite asphalt material, including the following weight parts of component: modified asphalt 70 parts, aggregate 22 parts, mineral powder 15 parts, filler modified hollow glass bead 11 parts and binder modified phenolic resin 6 parts.Wherein, aggregate is bentonite powder, bentonite powder is divided according to particle size, including particle size is 8-12mm continuous gradation, 500% of the total mass of aggregate;Particle size is 5-8mm continuous gradation, 50% of the total mass of aggregate;Mineral powder is quicklime powder, quicklime powder is divided according to particle size, including particle size is 4-6mm continuous gradation, 70% of the total mass of mineral powder;Particle size is 2-4mm continuous gradation, 30% of the total mass of mineral powder.

[0047] A kind of above-mentioned preparation method of road composite asphalt material, including the following steps:

[0048] Step S1, aggregate and mineral powder are mixed, preheated at 170 DEG C for 4 min, to obtain preheated mixture;

[0049] Step S2, modified asphalt is added to mixing kettle, heated to 175 DEG C, after mixing, the preheated mixture obtained in step S1 is added, stirs 3 min, modified hollow glass bead and binder modified phenolic resin are added, and then stirred and mixed for 8 min, to obtain road composite asphalt material.

[0050] The preparation method of modified asphalt in the embodiment is specifically as follows:

[0051] (1) the base asphalt is heated to 200 DEG C, and kept for 3h, to obtain molten asphalt;

[0052] (2) coupling agent γ-aminopropyl triethoxysilane is added to anhydrous ethanol and stirred and mixed uniformly, acetic acid is slowly added dropwise to adjust the pH value of the solution to 4-5, the above-mentioned solution is heated and stirred to 35 DEG C, and reacts for 30 min;Then, calcium sulfate whisker is added, and reacts for 50 min at 78 DEG C;While hot, wash and filter, to obtain modified calcium sulfate whisker;Wherein, the mass ratio of γ-aminopropyl triethoxysilane, anhydrous ethanol and calcium sulfate whisker is 1:32:18;

[0053] (3) the molten asphalt obtained in step (1) and SBS are placed in a shear machine with a shear speed of 4000 rpm for shear stirring for 35 min, rare earth compound cerium oxide powder and modified calcium sulfate whisker are slowly added at a temperature of 168 DEG C, mixed uniformly, and then mechanically stirred at a speed of 4000 rpm for 50 min, and after stirring is completed, it is placed for 1.5h, to obtain modified asphalt. Wherein, the mass ratio of molten asphalt, SBS, cerium oxide powder and modified calcium sulfate whisker is 1:0.7:0.2:0.35.

[0054] The preparation method of filler modified hollow glass bead in the embodiment is specifically as follows:

[0055] 1) hollow glass microspheres were placed in a beaker, sodium hydroxide solution was added, heated to 80℃ and refluxed for 2h, then washed with water until neutral, and dried to obtain pretreated hollow glass microspheres; wherein the ratio of the amount of hollow glass microspheres to sodium hydroxide solution was 1:0.35;

[0056] 2) the pretreated hollow glass microspheres obtained in step 1) were placed in a flask, anhydrous ethanol was added, then a coupling agent γ-aminopropyl triethoxysilane was added, and reacted at 82℃ for 3h, then washed, filtered and dried to obtain modified hollow glass microspheres; wherein the mass ratio of pretreated hollow glass microspheres to silane coupling agent was 1:0.18.

[0057] The preparation method of the binder modified phenolic resin in this embodiment is as follows:

[0058] Phenol and formaldehyde solution were mixed uniformly, under stirring, sodium hydroxide solution was added to adjust the pH to 7.5-8.5, the temperature was raised to 78℃ and reacted for 70min, then nano-lignin was added, the temperature was maintained at 88℃ and reacted for 2.8h, then the temperature was lowered to room temperature after montmorillonite was added and high-speed shearing stirring was continued for 1.2h, to obtain the modified phenolic resin. The molar ratio of phenol, formaldehyde and nano-lignin was 0.5:1.5:0.35; the mass percentage of formaldehyde in the formaldehyde solution was 37%; the amount of montmorillonite was 5% of the total mass of phenol, formaldehyde and nano-lignin.

[0059] Example 3

[0060] A road composite asphalt material, comprising the following components in parts by weight: modified asphalt 75 parts, aggregate 25 parts, mineral powder 10 parts, filler modified hollow glass microspheres 12 parts and binder modified phenolic resin 8 parts. The aggregate is bentonite powder, which is divided according to particle size, including continuous gradation with particle size of 8-12mm, accounting for 60% of the total mass of the aggregate; continuous gradation with particle size of 5-8mm, accounting for 40% of the total mass of the aggregate; the mineral powder is quicklime powder, which is divided according to particle size, including continuous gradation with particle size of 4-6mm, accounting for 80% of the total mass of the mineral powder; continuous gradation with particle size of 2-4mm, accounting for 20% of the total mass of the mineral powder.

[0061] A preparation method of the above road composite asphalt material, comprising the following steps:

[0062] Step S1, the aggregate and mineral powder were mixed and preheated at 180℃ for 3min to obtain a preheated mixture;

[0063] Step S2, the modified asphalt was added to a mixing pot and heated to 180℃, then the preheated mixture obtained in step S1 was added, stirred for 2min, then the modified hollow glass microspheres and the binder modified phenolic resin were added and stirred for 6min to obtain the road composite asphalt material.

[0064] The preparation method of the modified asphalt in the embodiment is specifically as follows:

[0065] (1) The base asphalt is heated to 220°C and kept for 2 hours to obtain molten asphalt;

[0066] (2) The coupling agent γ-aminopropyl triethoxysilane is added into anhydrous ethanol and stirred to mix uniformly, acetic acid is slowly added dropwise to adjust the pH value of the solution to 4-5, and the above solution is heated and stirred to 40°C and reacted for 20 minutes; then calcium sulfate whiskers are added, and the reaction is carried out at 80°C for 40 minutes; hot washing and filtration are performed to obtain modified calcium sulfate whiskers; wherein the mass ratio of γ-aminopropyl triethoxysilane, anhydrous ethanol and calcium sulfate whiskers is 1:40:20;

[0067] (3) The molten asphalt obtained in step (1) and SBS are placed in a shear machine with a shear speed of 4500 rpm for shear stirring for 30 minutes, rare earth compound cerium oxide powder and modified calcium sulfate whiskers are slowly added at a temperature of 170°C, mixed uniformly, and then mechanical stirring is carried out at a speed of 4500 rpm for 40 minutes, and after stirring is completed, it is left to stand for 2 hours to obtain modified asphalt. The mass ratio of molten asphalt, SBS, cerium oxide powder and modified calcium sulfate whiskers is 1:0.80.25(0.3).

[0068] The preparation method of the filler modified hollow glass microbeads in the embodiment is specifically as follows:

[0069] 1) The hollow glass microbeads are placed in a beaker, sodium hydroxide solution is added, and reflux reaction is carried out at 85°C for 1.5 hours, then washed with clean water until neutral, and dried to obtain pretreated hollow glass microbeads; wherein the dosage ratio of hollow glass microbeads to sodium hydroxide solution is 1:0.4;

[0070] 2) The pretreated hollow glass microbeads obtained in step 1) are placed in a flask, anhydrous ethanol is added, and then the coupling agent γ-aminopropyl triethoxysilane is added, and the reaction is carried out at 85°C for 2 hours, and then washed, filtered and dried to obtain modified hollow glass microbeads; wherein the mass ratio of pretreated hollow glass microbeads to silane coupling agent is 1:0.2.

[0071] The preparation method of the binder modified phenolic resin in the embodiment is specifically as follows:

[0072] Mixing phenol and formaldehyde solution uniformly, under stirring condition, adding sodium hydroxide solution to adjust pH to 7.5-8.5, increasing temperature to 80℃ and reacting for 60 min, adding nano-lignin, reacting for 2.5 h under 90℃, then maintaining temperature, adding montmorillonite and continuing high-speed shearing stirring for 1 h, and then decreasing to room temperature to obtain modified phenolic resin. The molar ratio of phenol, formaldehyde and nano-lignin is 0.6:1.8:0.4; the mass percentage of formaldehyde in the formaldehyde solution is 40%; and the amount of montmorillonite is 6% of the total mass of phenol, formaldehyde and nano-lignin.

[0073] Comparative Example 1

[0074] The road composite asphalt material and the preparation method thereof in the present comparative example are completely same as those in Example 2, and the only difference is that no rare earth compound cerium oxide powder is added in the modified asphalt.

[0075] Comparative Example 2

[0076] The road composite asphalt material and the preparation method thereof in the present comparative example are completely same as those in Example 2, and the only difference is that no modified calcium sulfate whisker is added in the modified asphalt.

[0077] Comparative Example 3

[0078] The road composite asphalt material and the preparation method thereof in the present comparative example are completely same as those in Example 2, and the only difference is that no SBS is added in the modified asphalt.

[0079] Comparative Example 4

[0080] The road composite asphalt material and the preparation method thereof in the present comparative example are completely same as those in Example 2, and the only difference is that the modified hollow glass microsphere is replaced by an equal amount of ordinary hollow glass microsphere.

[0081] Comparative Example 5

[0082] The road composite asphalt material and the preparation method thereof in the present comparative example are completely same as those in Example 2, and the only difference is that no nano-lignin is added in the modified phenolic resin.

[0083] Comparative Example 6

[0084] The road composite asphalt material and the preparation method thereof in the present comparative example are completely same as those in Example 2, and the only difference is that no montmorillonite is added in the modified phenolic resin.

[0085] Test Example

[0086] In order to further embody the technical effect of the present application, the road composite asphalt materials obtained in Examples 1-3 and Comparative Examples 1-6 are tested as follows:

[0087] The Highway Engineering Asphalt and Asphalt Mixture Test Regulation (JTG E20-2011) was used to test the road composite asphalt materials obtained in Examples 1-3 and Comparative Examples 1-6 as follows:

[0088] (1) Mechanical property test: the road composite asphalt materials obtained in Examples 1-3 and Comparative Examples 1-6 were tested for relevant mechanical properties according to the GB / T50784-2013 standard;

[0089] (2) Wear resistance test: the road composite asphalt materials obtained in Examples 1-3 and Comparative Examples 1-6 were tested for friction coefficient using a pendulum friction coefficient tester, the test points were taken for each sample, and 5 pendulum value tests were performed, then the average value of the 5 test readings represented the pendulum value of the test point, the friction coefficient of the road surface was calculated, and the calculation formula was: the friction coefficient of the road surface = the average value of the pendulum value of the test point / 100, which was the friction coefficient of the road surface;

[0090] The Highway Engineering Asphalt and Asphalt Mixture Test Regulation (JTG E20-2011) was used to test the road composite asphalt materials obtained in Examples 1-3 and Comparative Examples 1-6 as follows:

[0091] (3) High temperature stability test: the road composite asphalt materials were loaded into a test mold, rolled back and forth 8 times with a wheel roller, and then oven-cured according to the modified molding conditions, then the test piece was rolled back and forth 4 times, and after compaction and molding, it was placed in a ventilated room for 7 days, then the deformation after rolling of a certain load vehicle was tested to measure the high temperature stability;

[0092] (4) Low temperature crack resistance test: the road composite asphalt materials were loaded into a test mold, rolled back and forth 8 times with a wheel roller, then placed in a 5°C oven for 24h, then rolled back and forth 4 times after taking out, and then cured for 7 days to cut the small beam test piece, and then tested for low temperature crack resistance, with the bending tensile strength as the indicator of the low temperature crack resistance;

[0093] (5) Fatigue resistance test: the four-point bending beam test was used to test the fatigue resistance of the road composite asphalt materials;

[0094] (6) Aging resistance test: the road composite asphalt materials were placed in an aging test box, a 420W high-pressure mercury lamp was used as the aging lamp, an aluminum reflector lamp shade was installed, and the high-pressure mercury lamp was irradiated for 72h, and the softening point and ductility of the asphalt pavement material were recorded;

[0095] Table 1 Performance test results of the road composite asphalt materials prepared in Examples 1-3 and Comparative Examples 1-6

[0096]

[0097] As can be seen from the data in Table 1, the mechanical properties, wear resistance, high-temperature stability, low-temperature crack resistance, fatigue resistance and aging resistance of the road composite asphalt materials obtained in Examples 1-3 are all superior to those of Comparative Examples 1-6.

[0098] As can be seen from the comparison of Comparative Examples 1-3 and Example 2, because SBS has good viscoelasticity, it can help the asphalt to maintain sufficient flexibility in a low-temperature environment, thereby reducing the risk of cracking of the pavement due to temperature changes, and the structural support of the modified calcium sulfate whisker reduces the internal stress concentration of the pavement asphalt material during cold shrinkage, thereby reducing the formation of cracks, and the synergistic effect of SBS and the modified calcium sulfate whisker improves the low-temperature crack resistance and fatigue resistance of the road composite asphalt material; the cerium oxide is distributed in the three-dimensional grid structure of SBS, making the three-dimensional grid structure more compact and firm, thereby improving the aging resistance and high-temperature stability of the composite asphalt material, and at the same time, the cerium oxide plays a bridging role through its surface, making the asphalt molecules wrap or adsorb around the cerium oxide to form larger particles, and the existence of these particles also improves the high-temperature stability and wear resistance of the composite asphalt material; and because of the unique structure of the rare earth element, its numerous empty orbits of atoms and ions can capture free radicals, slowing down the generation of oxygen-containing functional groups in the asphalt aging process, thereby delaying the oxidation and aging process of the asphalt, and improving the aging resistance of the composite asphalt material. Moreover, by introducing amine groups and ethoxyl groups into the asphalt molecules through the modified calcium sulfate whisker, the amine groups and ethoxyl groups can react with the hydroxyl groups or carboxyl groups of the modified phenolic resin, increasing the bonding force between the asphalt material and the phenolic resin, thereby improving the mechanical properties of the composite asphalt material, and the synergistic effect of the modified calcium carbonate whisker and the mineral powder and aggregate also effectively improves the wear resistance, low-temperature crack resistance and mechanical properties of the composite asphalt material; in summary, the SBS, cerium oxide and modified calcium sulfate whisker composite modify the asphalt, and the three components play a synergistic effect, which can improve the comprehensive performance of the road composite asphalt material.

[0099] As can be seen from the comparison of Comparative Example 4 and Example 2, the present application uses silane coupling agent γ-aminopropyl triethoxysilane to modify the surface of the hollow glass microbeads, and the nitrogen atoms on the surface of the modified hollow glass microbeads form hydrogen bonds with the hydrogen atoms on the modified asphalt and the modified phenolic resin, thereby enhancing the interaction between the filler hollow glass microbeads and the modified asphalt and the modified phenolic resin, and improving the mechanical properties, aging resistance and high-temperature stability of the composite asphalt material.

[0100] As can be seen from the comparison of Comparative Examples 5-6 and Example 2, because the lignin contains a large number of hydroxyl groups, carboxyl groups, aromatic groups and the like, a large substituent group is introduced into the lignin-modified phenolic resin, and gradually cross-linked to form a macromolecular network structure, which makes the lignin-modified phenolic resin have high thermal stability and mechanical strength, and because of the characteristics of the montmorillonite, the addition of the montmorillonite can further enhance the high-temperature stability of the phenolic resin, thereby improving the high-temperature stability of the composite asphalt material; the lignin-modified phenolic resin can form a uniform cross-linked network during the curing process, fill the small pores and cracks in the composite asphalt material, and improve the mechanical strength of the composite asphalt material; and the montmorillonite has good swelling and filling properties, can form a fine filling layer in the composite asphalt material, further reduce internal defects and stress concentration points, and the lignin and the montmorillonite jointly modify the phenolic resin, so that the composite asphalt material can uniformly expand and contract under high and low temperature conditions, reduce the cracking phenomenon caused by uneven stress, thereby improving the high-temperature stability, low-temperature crack resistance and fatigue resistance of the composite asphalt material. The modified phenolic resin as a binder contains a variety of active groups such as hydroxyl groups and carboxyl groups on the molecular chain, which can chemically react or physically adsorb with the amine groups or other groups on the surface of the modified asphalt and the modified filler glass microspheres, form a firm chemical bond or physical combination, and this combination greatly enhances the interaction and compatibility between the composite asphalt materials, thereby improving the mechanical strength of the composite asphalt material, and at high temperatures, this combination can resist the damage of thermal stress, thereby improving the high-temperature stability and fatigue resistance of the composite asphalt material.

[0101] In summary, the matrix asphalt, the filler hollow glass microspheres and the binder phenolic resin are modified respectively, the modified asphalt, the modified hollow glass microspheres and the modified phenolic resin play a synergistic effect with the mineral powder and the aggregate, and the prepared road composite asphalt material has good mechanical properties, wear resistance, high-temperature stability, low-temperature crack resistance, aging resistance and fatigue resistance.

[0102] Finally, it should be noted that although the embodiments of the present application have been shown and described, those skilled in the art can understand that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and spirits of the present application, and any equivalent changes and improvements made within the scope of the present application should still fall within the scope of the present application.

Claims

1. A composite asphalt material for road use, characterized in that: The composite asphalt material for road use comprises the following components in parts by weight: 60-75 parts of modified asphalt, 18-25 parts of aggregate, 10-15 parts of mineral powder, 10-12 parts of filler-modified hollow glass microspheres, and 5-8 parts of binder-modified phenolic resin.

2. A composite asphalt material for road use according to claim 1, characterized in that: The preparation method of the modified asphalt is specifically as follows: (1) Heating the base asphalt to 180-220°C and keeping it warm for 2-4 hours to obtain molten asphalt; (2) adding the coupling agent γ-aminopropyltriethoxysilane to anhydrous ethanol and stirring to mix evenly, slowly adding acetic acid to adjust the pH value of the solution to 4-5, heating and stirring the above solution to 30-40°C, and reacting for 20-40 minutes; then adding calcium sulfate whiskers, and reacting at 75-80°C for 40-60 minutes; washing and filtering while hot to obtain modified calcium sulfate whiskers; (3) The molten asphalt obtained in step (1) and SBS are placed in a shearing machine with a shear speed of 3500-4500 rpm for shear stirring for 30-40 minutes. At a temperature of 165-170 ° C, rare earth compound cerium oxide powder and modified calcium sulfate whiskers are slowly added and mixed evenly. Then, mechanical stirring is carried out at a speed of 3500-4500 rpm for 40-60 minutes. After stirring, it is allowed to stand for 1-2 hours to obtain modified asphalt.

3. A composite asphalt material for road use according to claim 2, characterized in that: In the step (2), the mass ratio of the coupling agent γ-aminopropyltriethoxysilane, anhydrous ethanol and calcium sulfate whiskers is 1:(26-40):(14-20); in the step (3), the mass ratio of the molten asphalt to SBS, cerium oxide powder and modified calcium sulfate whiskers is 1:(0.5-0.8):(0.15-0.25):(0.3-0.4).

4. The composite asphalt material for road use according to claim 1, characterized in that: The aggregate is bentonite powder, which is classified by particle size into 8-12mm continuous gradation, accounting for 50-70% of the total mass of the aggregate; and 5-8mm continuous gradation, accounting for 30-50% of the total mass of the aggregate.

5. The composite asphalt material for road use according to claim 1, characterized in that: The mineral powder is quicklime powder, which is classified by particle size into 4-6mm continuous gradation, accounting for 60-80% of the total mass of the mineral powder; and 2-4mm continuous gradation, accounting for 20-40% of the total mass of the mineral powder.

6. The composite asphalt material for road use according to claim 1, characterized in that: The preparation method of the filler-modified hollow glass microspheres is as follows: 1) Place the hollow glass microspheres in a beaker, add sodium hydroxide solution, heat and reflux at 75-85° C. for 1.5-2.5 hours, then wash with water until neutral and dry to obtain pretreated hollow glass microspheres; 2) The pretreated hollow glass microspheres obtained in step 1) are placed in a flask, anhydrous ethanol is added, and then a coupling agent, γ-aminopropyltriethoxysilane, is added, and the mixture is reacted at 80-85° C. for 2-4 hours, washed, filtered, and dried to obtain modified hollow glass microspheres.

7. The composite asphalt material for road use according to claim 6, characterized in that: In the step 1), the ratio of the hollow glass microspheres to the sodium hydroxide solution is 1:(0.3-0.4); and in the step 2), the mass ratio of the pretreated hollow glass microspheres to the silane coupling agent is 1:(0.15-0.2).

8. The composite asphalt material for road use according to claim 1, characterized in that: The preparation method of the binder-modified phenolic resin is specifically as follows: Phenol and formaldehyde solution are mixed evenly, and sodium hydroxide solution is added under stirring to adjust the pH to 7.5-8.

5. The temperature is raised to 75-80°C and reacted for 60-80 minutes. Nano-lignin is added and reacted at 85-90°C for 2.5-3 hours. Then, montmorillonite is added while maintaining the temperature and high-speed shear stirring is continued for 1-1.5 hours. The temperature is then cooled to room temperature to obtain the modified phenolic resin.

9. The composite asphalt material for road use according to claim 8, characterized in that: The molar ratio of phenol, formaldehyde and nano-lignin is (0.48-0.6):(1.2-1.8):(0.32-0.4); the mass percentage of formaldehyde in the formaldehyde solution is 35-40%; and the amount of montmorillonite used is 4-6% of the total mass of phenol, formaldehyde and nano-lignin.

10. A method for preparing a composite asphalt material for road use according to any one of claims 1 to 9, characterized in that: The steps include: Step S1: mixing aggregate and mineral powder, and preheating at 160-180° C. for 3-5 minutes to obtain a preheated mixture; Step S2: Add the modified asphalt into a mixing pot, heat to 170-180° C., mix, add the preheated mixture obtained in step S1, stir for 2-4 minutes, add the modified hollow glass microspheres and the binder-modified phenolic resin, and stir and mix for another 6-10 minutes to obtain a composite asphalt material for road use.

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