Preparation method of anti-cracking asphalt

Abstract

The invention provides a preparation method of anti-cracking asphalt, and belongs to the technical field of compositions of asphalt materials, and the anti-cracking asphalt is prepared from the following raw materials in parts by weight: matrix asphalt, composite fibers, lauryl dimethyl amine oxide, carboxymethyl cellulose ether, UV-326 and water in a mass ratio of (90-110): (0.8-1.2): (0.24-0.36): (0.7-0.9): (0.45-0.55): (25-35). The anti-cracking asphalt disclosed by the invention is excellent in performance, the dynamic stability of a track test is 9493-9634 times / min, the low-temperature bending failure strain is 3200-3315 mu epsilon, the Marshall residual stability in water is 96.4-96.8%, the freeze-thaw splitting strength ratio is 94.9-95.8%, and the fatigue life is 2.4 * 10 < 6 >-2.6 * 10 < 6 > times.

Description

Technical Field

[0001] The present invention belongs to the technical field of asphalt material compositions, and particularly relates to a preparation method of anti-cracking asphalt. Background Art

[0002] Asphalt is a dark brown complex mixture composed of hydrocarbon compounds with different molecular weights and their non-metallic derivatives. It belongs to high-viscosity organic liquids, and its main components include asphaltenes, resins, etc. It is in a liquid, semi-solid or solid state at normal temperature and has characteristics such as waterproof, moisture-proof, and anti-corrosion. Asphalt is one of the most commonly used materials for building roads. However, asphalt is prone to softening at high temperatures and brittle cracking at low temperatures, resulting in insufficient durability and inability to meet more severe high and low temperature climate conditions. In the hot summer season, ruts are likely to appear on asphalt roads under heavy loads. In the cold winter season, temperature shrinkage cracks are likely to occur on asphalt roads, making it difficult to meet the road use requirements and safety requirements. With the improvement of traffic engineering grades, higher requirements are further put forward for the strength, deformation stability, fatigue durability, etc. of paving materials, and at the same time, special requirements such as high adhesiveness and water impermeability are also put forward in terms of use performance.

[0003] By modifying asphalt, including adding polymers such as rubber, fibers, resins, thermoplastic elastomers, etc. into asphalt, an elastic network structure is formed in the asphalt through swelling and adsorption. This network structure has ideal elasticity, plasticity, and extensibility, which improves the performance of asphalt.

[0004] Among them, fiber materials are cheap and abundant, so there are many studies on fiber-modified asphalt. However, the categories of fiber materials are numerous and complex, and their basic properties are quite different, resulting in differences in the modification effect of asphalt and the road use performance of modified asphalt mixtures. Among them, the factors that have a greater impact on the properties of asphalt mainly include the strength, heat resistance of the fiber itself, and the oil absorption rate and dispersibility in asphalt.

[0005] Patent CN117105555B discloses a composite fiber for asphalt pavement and its preparation method. In this solution, the composite fiber is formed by mixing modified wood fiber and modified high-silica glass fiber. Among them, the wood fiber is surface roughened with an alkaline compound and caprolactam, and the surface of the high-silica glass fiber is coated with a coupling agent. At the same time, the fibers are intertwined with each other, and the obtained composite fiber has good affinity with the asphalt matrix, and the strength and stability of the mixture are high. However, the modified wood fiber has a high oil absorption rate and adsorbs the light oil components in the asphalt, resulting in an increase in the relative content of asphaltenes and a significant increase in viscosity, which may affect the workability of construction and requires adjustment of construction temperature or process; the modified wood fiber and the modified high-silica glass fiber are intertwined with each other, although the strength is improved, but the dispersibility is also reduced, affecting the anti-cracking effect of asphalt. Summary of the Invention

[0006] In view of the problems existing in the prior art, the present invention provides a preparation method of crack-resistant asphalt to achieve the following invention purposes: to provide a crack-resistant asphalt, which has good low-temperature crack resistance, high-temperature stability and long-term fatigue resistance when applied to the road surface.

[0007] To solve the above technical problems, the technical solutions adopted by the present invention are as follows: A preparation method of crack-resistant asphalt, comprising the following raw materials in parts by weight: matrix asphalt, composite fiber, lauryl dimethyl amine oxide, carboxymethyl cellulose ether, UV-326, water, and the mass ratio is 90-110:0.8-1.2:0.24-0.36:0.7-0.9:0.45-0.55:25-35; The preparation method is as follows: add lauryl dimethyl amine oxide and carboxymethyl cellulose ether into water, stir at 80-120 r / min for 8-12 min to form an emulsion, then add it into the matrix asphalt at 140-180 °C, stir at 2000-4000 r / min until the asphalt cools to 40-60 °C, then add the composite fiber and UV-326, and continue to stir at the stirring rate for 15-25 min to obtain crack-resistant asphalt; The method for preparing the composite fiber includes basalt fiber pretreatment, preparation of PET emulsion, and compounding; The method for pretreating the basalt fiber is as follows: wash the basalt fiber with a length of 2-4 mm with deionized water, and then soak it in a silane coupling agent solution for 25-35 min to obtain pretreated basalt fiber; The silane coupling agent solution includes KH-570, ethanol, deionized water, and acetic acid, and the mass ratio of KH-570, ethanol, deionized water, and acetic acid is 0.8-1.2:70-90:18-20:0.08-0.12; The mass ratio of the basalt fiber to the silane coupling agent solution is 0.8-1.2:7-13; The method for preparing the PET emulsion is as follows: add sodium dodecyl sulfate into deionized water to make an emulsifier aqueous solution, then heat and melt the PET resin at 180-220 °C, add it into the emulsifier aqueous solution, stir at 2500-3500 r / min for 50-70 min, and finally perform ultrasonic treatment for 8-12 min to obtain the PET emulsion; The mass ratio of sodium dodecyl sulfate, deionized water, and PET resin is 2.5-3.5:90-110:30-40; The composite method is as follows: add pretreated basalt fibers and nano-SiO₂ into PET emulsion, after ultrasonic treatment for 10 - 20 min, filter, dry at 75 - 85 °C for 2.8 - 3.2 h, then perform heat treatment at 180 - 220 °C for 20 - 40 min to melt and crosslink the PET emulsion particles to form a continuous coating layer, then soak in concentrated sulfuric acid at 50 - 60 °C for 20 - 40 min, filter, dry at 45 - 55 °C for 1.5 - 2.5 h to obtain composite fibers; The mass ratio of the pretreated basalt fibers, nano-SiO₂, and PET emulsion is 4 - 6∶0.6 - 0.8∶18 - 22; The particle size of the nano-SiO₂ is 25 - 35 nm; The mass fraction of the concentrated sulfuric acid is 90 - 95%; For the composite fibers, the inner core basalt fiber has a diameter of 9 - 11 μm, and the outer PET skin has a thickness of 4 - 6 μm.

[0008] Compared with the prior art, the beneficial effects of the present invention are as follows: The composite fibers of the present invention adopt a core-shell structure, with the "shell" being PET fibers and the "core" being basalt fibers. PET fibers have a moderate oil absorption rate and good dispersibility in asphalt, but low strength. Basalt fibers have a low oil absorption rate and poor dispersibility in asphalt, but high strength. The composite fibers obtained through the core-shell structure make up for the deficiencies of both, having high strength, moderate oil absorption rate, and good dispersibility in asphalt; The breaking strength of the composite fibers of the present invention is 1983 - 1996 MPa, the elastic modulus is 9.0×10 3 ~9.2×10 3 MPa, the elongation at break is 2.2 - 2.4%, and the oil absorption rate is 291 - 305%; For the anti-cracking asphalt prepared by the present invention in road surface tests, the dynamic stability of the rutting test is 9493 - 9634 times / min, the low-temperature bending failure strain is 3200 - 3315 με, the residual stability of the immersion Marshall test is 96.4 - 96.8%, the freeze-thaw splitting strength ratio is 94.9 - 95.8%, and the fatigue life is 2.4×10 6 ~2.6×10 6 times. Detailed implementation manners

[0009] Example 1 1. Pretreatment of basalt fibers Clean basalt fibers with a length of 3 mm with deionized water, then soak them in a silane coupling agent solution for 30 min to obtain pretreated basalt fibers; The silane coupling agent solution includes KH-570, ethanol, deionized water, and acetic acid, where the mass ratio of KH-570, ethanol, deionized water, and acetic acid is 1∶80∶19∶0.1; The mass ratio of the basalt fiber to the silane coupling agent solution is 1∶10.

[0010] 2. Preparation of PET emulsion Sodium dodecyl sulfate is added to deionized water to make an emulsifier aqueous solution. Then, the PET resin is heated and melted at 200 °C and added to the emulsifier aqueous solution. It is stirred at 3000 r / min for 60 min, and finally ultrasonically treated for 10 min to obtain a PET emulsion; The mass ratio of sodium dodecyl sulfate, deionized water, and PET resin is 3∶100∶35.

[0011] 3. Composite The pretreated basalt fiber and nano-SiO₂ are added to the PET emulsion. After ultrasonically treating for 15 min, it is filtered, dried at 80 °C for 3 h, and then heat-treated at 200 °C for 30 min to melt and crosslink the PET emulsion particles to form a continuous coating layer. Then, it is soaked in concentrated sulfuric acid at 55 °C for 30 min, filtered, and dried at 50 °C for 2 h to obtain a composite fiber; The mass ratio of the pretreated basalt fiber, nano-SiO₂, and PET emulsion is 5∶0.7∶20; The particle size of the nano-SiO₂ is 30 nm; The mass fraction of the concentrated sulfuric acid is 93%; For the composite fiber, the inner core basalt fiber has a diameter of 10 μm, and the outer layer PET skin has a thickness of 5 μm.

[0012] 4. Mixing Lauryl dimethyl amine oxide and carboxymethyl cellulose ether are added to water and stirred at 100 r / min for 10 min to form an emulsion. Then, it is added to the matrix asphalt at 160 °C and stirred at 3000 r / min until the asphalt cools to 50 °C. Then, the composite fiber and UV-326 are added, and the stirring rate is maintained and stirred for another 20 min to obtain crack-resistant asphalt; The mass ratio of the matrix asphalt, composite fiber, lauryl dimethyl amine oxide, carboxymethyl cellulose ether, UV-326, and water is 100∶1∶0.3∶0.8∶0.5∶30.

[0013] Example 2 1. Pretreatment of basalt fiber The basalt fiber with a length of 2 mm is cleaned with deionized water and then added to the silane coupling agent solution and soaked for 25 min to obtain the pretreated basalt fiber; The silane coupling agent solution includes KH-570, ethanol, deionized water, and acetic acid, where the mass ratio of KH-570, ethanol, deionized water, and acetic acid is 0.8∶70∶18∶0.08; The mass ratio of the basalt fiber to the silane coupling agent solution is 0.8∶7.

[0014] 2. Preparation of PET emulsion Sodium dodecyl sulfate is added to deionized water to make an aqueous emulsifier solution. Then, PET resin is heated and melted at 180°C and added to the aqueous emulsifier solution. It is stirred at 2500 r / min for 50 min, and finally ultrasonically treated for 8 min to obtain a PET emulsion; The mass ratio of sodium dodecyl sulfate, deionized water, and PET resin is 2.5∶90∶30.

[0015] 3. Composite The pretreated basalt fiber and nano-SiO2 are added to the PET emulsion. After ultrasonically treating for 10 min, it is filtered, dried at 75°C for 2.8 h, and then heat-treated at 180°C for 20 min to melt and crosslink the PET emulsion particles. Then, it is soaked in concentrated sulfuric acid at 50°C for 20 min, filtered, and dried at 45°C for 1.5 h to form a continuous coating layer, obtaining composite fibers; The mass ratio of the pretreated basalt fiber, nano-SiO2, and PET emulsion is 4∶0.6∶18; The particle size of the nano-SiO2 is 25 nm; The mass fraction of the concentrated sulfuric acid is 90%; For the composite fiber, the diameter of the inner core basalt fiber is 9 μm, and the thickness of the outer layer PET skin is 4 μm.

[0016] 4. Mixing Lauryl dimethyl amine oxide and carboxymethyl cellulose ether are added to water and stirred at 80 r / min for 8 min to form an emulsion. Then, it is added to the matrix asphalt at 140°C and stirred at 2000 r / min until the asphalt cools to 40°C. Then, composite fibers and UV-326 are added, and the stirring rate is maintained and stirred for another 15 min to obtain anti-cracking asphalt; The mass ratio of the matrix asphalt, composite fiber, lauryl dimethyl amine oxide, carboxymethyl cellulose ether, UV-326, and water is 90∶0.8∶0.24∶0.7∶0.45∶25.

[0017] Example 3 1. Pretreatment of basalt fiber The basalt fiber with a length of 4 mm is cleaned with deionized water and then added to the silane coupling agent solution and soaked for 35 min to obtain the pretreated basalt fiber; The silane coupling agent solution includes KH-570, ethanol, deionized water, and acetic acid, where the mass ratio of KH-570, ethanol, deionized water, and acetic acid is 1.2∶90∶20∶0.12; The mass ratio of the basalt fiber to the silane coupling agent solution is 1.2∶13.

[0018] 2. Preparation of PET emulsion Sodium dodecyl sulfate is added to deionized water to make an aqueous solution of emulsifier, and then the PET resin is heated and melted at 220°C and added to the aqueous solution of emulsifier. It is stirred at 3500 r / min for 70 min and finally ultrasonically treated for 12 min to obtain a PET emulsion; The mass ratio of the sodium dodecyl sulfate, deionized water, and PET resin is 3.5∶110∶40.

[0019] 3. Composite The pretreated basalt fiber and nano-SiO2 are added to the PET emulsion. After ultrasonically treating for 20 min, it is filtered, dried at 85°C for 3.2 h, and then heat-treated at 220°C for 40 min to melt and crosslink the PET emulsion particles to form a continuous coating layer. Then it is soaked in concentrated sulfuric acid at 60°C for 40 min, filtered, and dried at 55°C for 2.5 h to obtain composite fibers; The mass ratio of the pretreated basalt fiber, nano-SiO2, and PET emulsion is 6∶0.8∶22; The particle size of the nano-SiO2 is 35 nm; The mass fraction of the concentrated sulfuric acid is 95%; For the composite fiber, the inner core basalt fiber has a diameter of 11 μm and the outer layer PET skin has a thickness of 6 μm.

[0020] 4. Mixing Lauryl dimethyl amine oxide and carboxymethyl cellulose ether are added to water and stirred at 120 r / min for 12 min to form an emulsion, and then added to the matrix asphalt at 180°C. After stirring at 4000 r / min until the asphalt cools to 60°C, the composite fiber and UV-326 are added, and the stirring rate is maintained to continue stirring for 25 min to obtain anti-cracking asphalt; The mass ratio of the matrix asphalt, composite fiber, lauryl dimethyl amine oxide, carboxymethyl cellulose ether, UV-326, and water is 110∶1.2∶0.36∶0.9∶0.55∶35.

[0021] Example 4 Add lauryldimethylamine oxide and carboxymethyl cellulose ether to water, stir at 120 r / min for 12 min to form an emulsion, then add it to the matrix asphalt at 180 °C, stir at 4000 r / min until the asphalt cools to 60 °C, add basalt fiber and UV-326, and continue stirring at the same stirring rate for 25 min to obtain crack-resistant asphalt; The mass ratio of the matrix asphalt, basalt fiber, lauryldimethylamine oxide, carboxymethyl cellulose ether, UV-326, and water is 110∶1.2∶0.36∶0.9∶0.55∶35.

[0022] Example 5 Add lauryldimethylamine oxide and carboxymethyl cellulose ether to water, stir at 120 r / min for 12 min to form an emulsion, then add it to the matrix asphalt at 180 °C, stir at 4000 r / min until the asphalt cools to 60 °C, add PET fiber and UV-326, and continue stirring at the same stirring rate for 25 min to obtain crack-resistant asphalt; The mass ratio of the matrix asphalt, PET fiber, lauryldimethylamine oxide, carboxymethyl cellulose ether, UV-326, and water is 110∶1.2∶0.36∶0.9∶0.55∶35.

[0023] Test Example 1. Performance test of crack-resistant asphalt Use the composite fibers prepared in Examples 1-3, the basalt fiber in Example 4, and the PET fiber in Example 5, and test the breaking strength, elastic modulus, elongation at break, and oil absorption rate according to JT / T 776.1-2010. The test results are shown in Table 1; Table 1

[0024] 2. Performance test of crack-resistant asphalt in road applications By weight, mix 4.5 parts of crack-resistant asphalt, 65 parts of crushed stone, 20 parts of stone chips, and 8 parts of mineral powder to obtain an asphalt mixture. The dynamic stability of the rutting test, the failure strain of the low-temperature bending test, the residual stability of the immersed Marshall test, and the freeze-thaw splitting strength ratio are respectively referred to the test methods of T0719, T0715, T0709, and T0729 in the specifications of JTG F40—2004 and "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG E20—2011), and the fatigue life of the asphalt mixture is tested according to the four-point bending fatigue test in JT / T 860.8—2023; The crack-resistant asphalt is the crack-resistant asphalt prepared in Examples 1-5 respectively; The test results are shown in Table 2; Table 2

Claims

1. A preparation method of anti-cracking asphalt, characterized in that: It includes the following raw materials in parts by weight: matrix asphalt, composite fiber, lauryldimethylamine oxide, carboxymethyl cellulose ether, UV-326, and water; The preparation method of the anti-cracking asphalt is as follows: Add lauryldimethylamine oxide and carboxymethyl cellulose ether into water, stir to form an emulsion, then add it into the matrix asphalt at 140-180 °C, stir at 2000-4000 r / min until the asphalt cools to 40-60 °C, then add composite fiber and UV-326, and continue to stir at the stirring rate for 15-25 min to obtain anti-cracking asphalt; The preparation method of the composite fiber is as follows: Add pretreated basalt fiber and nano-SiO2 into PET emulsion, ultrasonic treat for 10-20 min, then filter and dry, and heat-treat at 180-220 °C for 20-40 min to melt and crosslink the PET emulsion particles to form a continuous coating layer, then soak in concentrated sulfuric acid at 50-60 °C for 20-40 min, filter and dry to obtain the composite fiber.

2. The preparation method of an anti-cracking asphalt according to claim 1, characterized in that: In the preparation method of the composite fiber, the mass ratio of pretreated basalt fiber, nano-SiO2, and PET emulsion is 4-6:0.6-0.8:18-22; the particle size of nano-SiO2 is 25-35 nm; the mass fraction of concentrated sulfuric acid is 90-95%; for the composite fiber, the diameter of the inner core basalt fiber is 9-11 μm, and the thickness of the outer layer PET skin is 4-6 μm.

3. The preparation method of an anti-cracking asphalt according to claim 1, characterized in that: In the preparation method of the anti-cracking asphalt, the mass ratio of matrix asphalt, composite fiber, lauryldimethylamine oxide, carboxymethyl cellulose ether, UV-326, and water is 90-110:0.8-1.2:0.24-0.36:0.7-0.9:0.45-0.55:25-35.

4. The preparation method of an anti-cracking asphalt according to claim 1, characterized in that: The preparation method of the pretreated basalt fiber is as follows: Wash the basalt fiber with a length of 2-4 mm with deionized water, and then soak it in a silane coupling agent solution for 25-35 min to obtain the pretreated basalt fiber.

5. The preparation method of an anti-cracking asphalt according to claim 4, characterized in that: In the preparation method of the pretreated basalt fiber, the silane coupling agent solution includes KH-570, ethanol, deionized water, and acetic acid, and the mass ratio of KH-570, ethanol, deionized water, and acetic acid is 0.8-1.2:70-90:18-20:0.08-0.12; the mass ratio of basalt fiber to the silane coupling agent solution is 0.8-1.2:7-13.

6. The preparation method of an anti-cracking asphalt according to claim 1, wherein: The preparation method of the PET emulsion is as follows: Add sodium dodecyl sulfate into deionized water to make an emulsifier aqueous solution, then heat and melt PET resin at 180-220 °C, add it into the emulsifier aqueous solution, stir at 2500-3500 r / min for 50-70 min, and finally ultrasonic treat for 8-12 min to obtain the PET emulsion.

7. The preparation method of an anti-cracking asphalt according to claim 6, wherein: In the preparation method of the PET emulsion, the mass ratio of sodium dodecyl sulfate, deionized water, and PET resin is 2.5-3.5:90-110:30-40.

Images