A kind of renewable asphalt mixture and preparation method thereof

Abstract

The present invention belongs to the field of asphalt materials, and specifically relates to a renewable asphalt mixture and a preparation method thereof, comprising the following steps: weighing asphalt pavement milling material and emulsifier by weight, preheating, swelling and developing, then adding modified recycled plastic, regeneration agent, epoxy resin and basalt fiber for shearing, cooling to room temperature, and obtaining a renewable asphalt mixture. Among them, the modified recycled plastic is prepared by the following steps: S1, preparing polylactic acid-polyhydroxyalkanoate copolymer; S2, putting polylactic acid-polyhydroxyalkanoate copolymer and recycled plastic into a high-speed mixer to prepare modified recycled plastic. The present invention realizes the recycling of waste asphalt pavement materials and recycled plastics by using asphalt pavement milling material and recycled plastics as the main raw materials, reduces dependence on new resources and waste emissions, and is beneficial to environmental protection and sustainable development. At the same time, the production cost of renewable asphalt mixture is reduced and economic benefits are improved.

Description

Technical Field

[0001] The invention belongs to the field of asphalt materials, and specifically relates to a renewable asphalt mixture and a preparation method thereof. Background Art

[0002] Asphalt mixture regeneration technology is a technology that restores or improves the performance of damaged or aged asphalt pavement through specific process treatment. First, the old asphalt concrete pavement is excavated, crushed and screened, and then the treated old materials are mixed with new aggregates, asphalt and necessary regeneration agents to produce a regenerated asphalt mixture with the expected road performance. By recycling and reusing waste asphalt mixtures, the use of new asphalt is reduced, thereby reducing the consumption of resources such as oil. Regeneration technology can greatly restore the various properties of the original asphalt mixture. After reasonable heating and mixing treatment, the old asphalt mixture can be fully integrated with new asphalt, regeneration agents, etc. to form a regenerated mixture with excellent road performance. According to specific process and technical conditions, there are two main technical approaches for the regeneration of asphalt mixtures: hot regeneration and cold regeneration. Hot regeneration technology is to heat the old materials and new asphalt and other materials to a certain temperature and then mix them. The heating treatment can promote the melting of the old asphalt and the penetration of the new asphalt, thereby achieving a good mixing effect. The cold recycling technology is to mix at a lower temperature, and through the addition of specific regeneration agents and mixing equipment, the old asphalt mixture is fully integrated with the new material.

[0003] In the existing technology, sand and gravel are often used as aggregates for asphalt mixtures. The current excessive exploitation and use of sand and gravel has put a certain amount of pressure on natural resources and the environment. At the same time, recycling technology is highly dependent on specific regeneration agents. The lack of suitable regeneration agents or unstable quality directly affects the performance of recycled mixtures, increasing costs and environmental pressures. In addition, the compatibility and bonding strength of recycled plastics with asphalt matrices are usually poor, which leads to cracking of recycled asphalt in subsequent use. Summary of the invention

[0004] The purpose of the present invention is to provide a renewable asphalt mixture and a preparation method thereof in view of the deficiencies of the prior art.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A renewable asphalt mixture comprises the following raw materials by weight: 100-120 parts of asphalt pavement milling material, 20-24 parts of modified recycled plastic, 10-15 parts of regeneration agent, 5-7 parts of epoxy resin, 3-5 parts of emulsifier and 0.05-0.09 parts of basalt fiber.

[0007] Preferably, the following raw materials are included by weight: 100-110 parts of asphalt pavement milling material, 20-22 parts of modified recycled plastic, 10-12 parts of regeneration agent, 5 parts of epoxy resin, 3-4 parts of emulsifier and 0.05-0.07 parts of basalt fiber.

[0008] Furthermore, the modified recycled plastic is prepared by the following steps:

[0009] S1, adding polylactic acid and polyhydroxyalkanoate to an acetone solution, adding N-hydroxysuccinimide, controlling the temperature at 60-80°C under the protection of nitrogen, stirring with a magnetic stirrer, reacting for 3-5 hours, cooling to room temperature, filtering, washing with deionized water, and drying to obtain a polylactic acid-polyhydroxyalkanoate copolymer;

[0010] S2. Put the polylactic acid-polyhydroxyalkanoate copolymer and the recycled plastic into a high-speed mixer and mix them evenly. Add the blended materials into an extruder. By rotating the extruder screw, control the temperature at 120-140°C to melt the materials and extrude them into strips. Then cool them through a cooling water trough and finally cut them into granules according to the required particle size through a pelletizer.

[0011] The regeneration agent is biodiesel.

[0012] The epoxy resin includes one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, novolac epoxy resin, glycerol epoxy resin and ethylene glycol epoxy resin.

[0013] The emulsifier includes one or more of OP-10, Tween 80, cetyltrimethylammonium bromide, sodium lauryl sulfate and PEG fatty acid ester.

[0014] Furthermore, in the step S1, the mass ratio of polylactic acid, polyhydroxyalkanoate and N-hydroxysuccinimide is (10-15): (14-18): (1-2), and the mass ratio of polylactic acid-polyhydroxyalkanoate copolymer and recycled plastic in the step S2 is (3-5): (6-8).

[0015] According to another aspect of the present invention, a method for preparing a renewable asphalt mixture is provided, comprising the following steps:

[0016] Asphalt pavement milling material and emulsifier are weighed by weight, preheated to 120-140° C., swelled for 5-10 minutes, and then modified recycled plastic, regeneration agent, epoxy resin and basalt fiber are added, sheared at 2000-2500 rpm and 180-220° C. for 30-35 minutes, and cooled to room temperature to obtain a renewable asphalt mixture.

[0017] Beneficial effects of the present invention:

[0018] 1. In the technical solution of the present invention, polylactic acid (PLA) and polyhydroxyalkanoate (PHA) are copolymerized to form a PLA-PHA copolymer having a relatively long molecular chain and a branched structure. The recycled asphalt forms a continuous and stable three-dimensional network structure with the copolymer through the interaction of polar components, thereby being able to form effective physical and chemical cross-linking points in the asphalt, thereby enhancing the compatibility and bonding strength between the recycled plastic and the asphalt mixture.

[0019] 2. In the technical solution of the present invention, the modified recycled plastic is evenly dispersed in the asphalt in the form of tiny particles and / or fibers, which helps to increase the cohesion of the asphalt mixture and improve its crack resistance and durability.

[0020] 3. In the technical solution of the present invention, the PLA-PHA copolymer has a high melting point and glass transition temperature, can maintain good stability at high temperatures, and reduce the flow deformation of asphalt. At the same time, the addition of recycled plastics can increase the viscosity of the asphalt mixture and improve its high temperature anti-rutting performance.

[0021] 4. In the technical solution of the present invention, asphalt pavement milling material and recycled plastic are used as the main raw materials, which realizes the recycling of waste asphalt pavement materials and recycled plastics, reduces the dependence on new resources and the discharge of waste, and is beneficial to environmental protection and sustainable development. At the same time, it reduces the production cost of renewable asphalt mixture and improves economic benefits. DETAILED DESCRIPTION

[0022] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Example 1

[0024] The modified recycled plastics are prepared by the following steps:

[0025] S1. Add 10 g of polylactic acid and 14 g of polyhydroxyalkanoate to an acetone solution, add 1 g of N-hydroxysuccinimide, control the temperature at 60° C. under the protection of nitrogen, stir with a magnetic stirrer, react for 3 h, cool to room temperature, filter, wash with deionized water, and dry to obtain a polylactic acid-polyhydroxyalkanoate copolymer;

[0026] S2. Put 30g of polylactic acid-polyhydroxyalkanoate copolymer and 60g of recycled plastic into a high-speed mixer and mix them evenly. Add the blended materials into an extruder. By rotating the extruder screw, control the temperature at 120°C to melt the materials and extrude them into strips. Then cool them through a cooling water trough, and finally cut them into granules according to the required particle size through a pelletizer.

[0027] Example 2

[0028] The modified recycled plastics are prepared by the following steps:

[0029] S1, adding 12.5g of polylactic acid and 16g of polyhydroxyalkanoate to an acetone solution, adding 1.5g of N-hydroxysuccinimide, controlling the temperature at 60°C under the protection of nitrogen, stirring with a magnetic stirrer, reacting for 3h, cooling to room temperature, filtering, washing with deionized water, and drying to obtain a polylactic acid-polyhydroxyalkanoate copolymer;

[0030] S2. Put 40g of polylactic acid-polyhydroxyalkanoate copolymer and 70g of recycled plastic into a high-speed mixer and mix them evenly. Add the blended materials into an extruder. By rotating the extruder screw, control the temperature at 120°C to melt the materials and extrude them into strips. Then cool them through a cooling water trough and finally cut them into granules according to the required particle size through a pelletizer.

[0031] Example 3

[0032] The modified recycled plastics are prepared by the following steps:

[0033] S1. Add 15 g of polylactic acid and 18 g of polyhydroxyalkanoate to an acetone solution, add 2 g of N-hydroxysuccinimide, control the temperature at 60° C. under the protection of nitrogen, stir with a magnetic stirrer, react for 3 h, cool to room temperature, filter, wash with deionized water, and dry to obtain a polylactic acid-polyhydroxyalkanoate copolymer;

[0034] S2. Put 50g of polylactic acid-polyhydroxyalkanoate copolymer and 80g of recycled plastic into a high-speed mixer and mix them evenly. Add the blended materials into an extruder. By rotating the extruder screw, control the temperature at 120°C to melt the materials and extrude them into strips. Then cool them through a cooling water trough and finally cut them into granules according to the required particle size through a pelletizer.

[0035] Example 4

[0036] A method for preparing a renewable asphalt mixture comprises the following steps:

[0037] 100 parts of asphalt pavement milling material and 3 parts of emulsifier were weighed by weight, preheated to 120°C, and swelled for 5 minutes. Then, 20 parts of modified recycled plastic prepared in Example 1, 10 parts of regeneration agent, 5 parts of epoxy resin and 0.05 parts of basalt fiber were added, and sheared at 2000 rpm and 180°C for 30 minutes. The mixture was cooled to room temperature to obtain a renewable asphalt mixture.

[0038] Example 5

[0039] A method for preparing a renewable asphalt mixture comprises the following steps:

[0040] 105 parts of asphalt pavement milling material and 3.5 parts of emulsifier were weighed by weight and preheated to 120°C. The mixture was swelled for 5 minutes. Then 21 parts of modified recycled plastic prepared in Example 2, 11 parts of regeneration agent, 5 parts of epoxy resin and 0.06 parts of basalt fiber were added. The mixture was sheared at 2000 rpm and 180°C for 30 minutes. The mixture was cooled to room temperature to obtain a renewable asphalt mixture.

[0041] Example 6

[0042] A method for preparing a renewable asphalt mixture comprises the following steps:

[0043] 110 parts of asphalt pavement milling material and 4 parts of emulsifier were weighed by weight and preheated to 120°C. The mixture was swelled for 5 minutes. Then 22 parts of the modified recycled plastic prepared in Example 3, 12 parts of the regeneration agent, 5 parts of epoxy resin and 0.07 parts of basalt fiber were added. The mixture was sheared at 2000 rpm and 180°C for 30 minutes. The mixture was cooled to room temperature to obtain a renewable asphalt mixture.

[0044] Comparative Example 1

[0045] In this comparative example, only recycled plastics were used, and the remaining steps were the same as those in Example 4. That is, 100 parts of asphalt pavement milling material and 3 parts of emulsifier were weighed by weight, preheated to 120°C, swelled for 5 minutes, and then 20 parts of recycled plastics, 10 parts of regeneration agent, 5 parts of epoxy resin and 0.05 parts of basalt fiber were added, sheared at 2000 rpm and 180°C for 30 minutes, and cooled to room temperature to obtain a renewable asphalt mixture.

[0046] Sufficient quantities of renewable asphalt mixture samples were prepared according to the preparation methods of Examples 4-6 and Comparative Example 1. Performance tests were performed on each sample according to JTG E20-2011 "Testing Procedures for Asphalt and Asphalt Mixtures for Highway Engineering", and the results are shown in Table 1:

[0047] Table 1. Performance test results of Examples 1-6 and Comparative Example 1

[0048] project Example 4 Example 5 Example 6 Comparative Example 1 Marshall stability (kN) 11.83 11.68 11.91 8.62 Flow value(mm) 2.47 2.58 2.49 3.21 Viscosity (Pa·s) 1.64 1.62 1.57 0.71 Shear stress (MPa) 0.98 0.95 0.96 0.68 Softening point(℃) 62 63 63 50

[0049] According to the technical requirements for the design of emulsified asphalt cold recycled mixture in GB 50092-201x "Asphalt Pavement Construction and Acceptance Standard" (Draft for Comments), samples of Examples 4-6 and Comparative Example 1 were tested, and the results are shown in Table 2:

[0050] Table 2. Technical index results of Examples 1-6 and Comparative Example 1

[0051]

[0052]

[0053] As can be seen from Table 1, the Marshall stability of Examples 4-6 is much higher than that of Comparative Example 1, indicating that the deformation resistance is stronger. In terms of flow value, the flow value of Examples 4-6 is lower, indicating that it has better resistance to flow. In terms of viscosity and shear stress, the values ​​of Examples 4-6 are higher, showing better adhesion and shear resistance. In addition, the softening point of Examples 4-6 is significantly higher than that of Comparative Example 1, indicating that they have better stability at high temperatures.

[0054] As can be seen from Table 2, Example 4-6 has a moderate porosity and can provide good drainage performance. The splitting strength and dry-wet splitting strength of Example 4-6 are relatively high, indicating good crack resistance and water stability. At the same time, the freeze-thaw splitting strength ratio of Example 4-6 is also relatively high, showing good freeze-thaw resistance. In terms of dynamic stability at 60°C, Examples 4-6 all exceed the standard requirement of 2500 times / mm, while Comparative Example 1 does not reach 2000 times / mm, indicating that Example 4-6 has better rutting resistance at high temperatures. All indicators of Example 4-6 meet the technical requirements of the "Asphalt Pavement Construction and Acceptance Standards".

[0055] In summary, the renewable asphalt mixtures prepared in Examples 4-6 have significant advantages in various performance indicators and technical indicators over Comparative Example 1. Due to the introduction of modified recycled plastics, the physical properties and stability of the mixture can be improved, making the renewable asphalt mixture have better performance in practical applications.

[0056] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0057] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A renewable asphalt mixture, characterized in that: The raw materials include the following by weight: 100-120 parts of asphalt pavement milling material, 20-24 parts of modified recycled plastic, 10-15 parts of regeneration agent, 5-7 parts of epoxy resin, 3-5 parts of emulsifier and 0.05-0.09 parts of basalt fiber; The modified recycled plastics are prepared by the following steps: S1, adding polylactic acid and polyhydroxyalkanoate to an acetone solution, adding N-hydroxysuccinimide, controlling the temperature at 60-80°C under the protection of nitrogen, stirring with a magnetic stirrer, reacting for 3-5 hours, cooling to room temperature, filtering, washing with deionized water, and drying to obtain a polylactic acid-polyhydroxyalkanoate copolymer; S2, putting polylactic acid-polyhydroxyalkanoate copolymer and recycled plastic into a high-speed mixer and mixing them evenly, adding the blended materials into an extruder, controlling the temperature at 120-140° C. by rotating the extruder screw, so that the materials are melted and extruded into strips, then cooled by a cooling water tank, and finally cut into granules according to the required particle size by a pelletizer; The regeneration agent is biodiesel; The epoxy resin includes one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, novolac epoxy resin, glycerol epoxy resin and ethylene glycol epoxy resin; The emulsifier includes one or more of OP-10, Tween 80, cetyltrimethylammonium bromide, sodium lauryl sulfate and PEG fatty acid ester; The mass ratio of polylactic acid, polyhydroxyalkanoate and N-hydroxysuccinimide in step S1 is (10-15): (14-18): (1-2), and the mass ratio of polylactic acid-polyhydroxyalkanoate copolymer and recycled plastic in step S2 is (3-5): (6-8).

2. A renewable asphalt mixture according to claim 1, characterized in that: The raw materials include the following by weight: 100-110 parts of asphalt pavement milling material, 20-22 parts of modified recycled plastic, 10-12 parts of regeneration agent, 5 parts of epoxy resin, 3-4 parts of emulsifier and 0.05-0.07 parts of basalt fiber.

3. The method for preparing a renewable asphalt mixture according to claim 1, characterized in that: The following steps are involved: Asphalt pavement milling material and emulsifier are weighed by weight, preheated to 120-140° C., swelled for 5-10 minutes, and then modified recycled plastic, regeneration agent, epoxy resin and basalt fiber are added, sheared at 2000-2500 rpm and 180-220° C. for 30-35 minutes, and cooled to room temperature to obtain a renewable asphalt mixture.

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