Preparation method of recycled asphalt and application thereof

Abstract

The present application relates to a kind of preparation method and application of recycled asphalt, waste modified asphalt waterproofing membrane is cut into cutting material by cutting machine, cutting material is put into special double screw extruder, and is converted into molten state recycled asphalt.The present application also utilizes layered silicate clay and biodegradable resin to modify recycled asphalt, for preparing recycled asphalt system modified asphalt or recycled asphalt containing waterproofing membrane, realizes the recycling of waste modified asphalt waterproofing membrane, especially for the recycling of waste modified asphalt waterproofing membrane containing polyester fiber, recycled asphalt system modified asphalt prepared by recycled asphalt can also reduce the dependence on petroleum chemical composition-artificial synthetic rubber required for traditional modified asphalt, and the preparation method of the present application also has the advantages of low energy consumption, little pollution, reduce carbon dioxide emissions and the like relative to existing recycling technology.

Description

Technical Field

[0001] This invention relates to the field of waterproof materials technology, and in particular to a method for preparing recycled asphalt and its application. Background Technology

[0002] Waste modified bitumen waterproof membrane mainly includes substandard modified bitumen waterproof membrane products, used or aged waterproof membrane removed from buildings, and scraps generated during the production of modified bitumen waterproof membrane. Traditional recycling methods for these materials are limited to simple crushing, pre-melting heating, or granulation for reuse. For example:

[0003] CN112609476A discloses a method for preparing waterproof membrane by modifying asphalt-based waste waterproof membrane. The method involves heating the recycled waterproof membrane to 220-270°C in a reactor and continuing to heat it for 4 hours. After the recycled waterproof membrane melts, the temperature is cooled to 180-220°C to obtain the final product.

[0004] CN107879674A discloses a method for recycling and reusing waterproof membrane and a modified bitumen mixture. The specification discloses that the recycled waterproof membrane is cut into small pieces with a length and width of 5-10mm, and then the recycled waterproof membrane is mixed with aggregate at a certain mass ratio and stirred evenly at a certain temperature to obtain a mixture; then base bitumen is added to the obtained mixture and stirred evenly to obtain a modified bitumen mixture.

[0005] CN109867981A discloses a modified flame-retardant material containing waste plastics. The specification discloses the following steps: Step 1: Waste waterproof membrane is crushed into granules using a crusher, and then melt-modified using nano-silica and a coupling agent to obtain modified plastics; Step 2: The modified plastics prepared in Step 1 and other components are added to a high-speed mixer, heated to 60~70℃, stirred for 1~2 hours, then other components are added and the temperature is further raised to 80~90℃, stirred for 20~30 minutes to obtain a mixture; Step 3: The mixture prepared in Step 2 is melt-extruded and granulated in a twin-screw extruder, wherein the temperature is 180~190℃ and the screw speed is 350~400 rpm.

[0006] The aforementioned existing technologies all utilize different heating methods for recycling waterproof membranes. However, because the polyester fiber fabric used in modified bitumen waterproof membranes is primarily composed of polyethylene terephthalate (PET), which has a high melting point, typically around 260-280°C, and possesses certain strength and elongation, melting the polyester fiber fabric using only heating methods would require a prolonged melting process at temperatures exceeding the polyester fiber fabric's melting point, consuming significant amounts of thermal energy.

[0007] CN101550729A discloses a method for preparing asphalt-modified thermoplastic polyolefin waterproof membrane. The specification describes mixing petroleum asphalt with a small amount of TPO resin in a mixer, then extruding and granulating the mixture in a screw extruder to produce a modified asphalt masterbatch. The masterbatch is then mixed with other components, including recycled TPO material, in the main layer, and melt-extruded in a screw extruder. The recycled TPO material is waste material, scrap, or recycled waste TPO membrane from the production process. The screw and die head temperatures during the preparation of the modified asphalt masterbatch are 120-150°C; the screw and die head temperatures during the melt extrusion of the upper surface layer are 180-200°C. This patent mixes recycled TPO resin with asphalt and produces modified asphalt masterbatch using a screw extruder. Because asphalt has a low softening point, typically around 45°C, and because asphalt differs from recycled modified asphalt waterproof membranes in that its composition is relatively simple, the processing requirements for the polyester fiber fabric in the recycled waterproof membrane are not considered.

[0008] Based on the above-mentioned existing technology, there are several technical problems that urgently need to be solved, such as the inability to fully recycle waterproof membranes containing polyester fibers, the high energy consumption and pollution of recycling, the inability to fully recycle recycled asphalt materials, and the lack of reprocessing and utilization of recycled asphalt materials. Summary of the Invention

[0009] To address the aforementioned technical problems, this invention provides a method for recycling and regenerating waste modified bitumen waterproof membranes, particularly for waste waterproof membranes containing polyester fibers. Specifically, this invention provides a method for preparing recycled bitumen, comprising the following steps:

[0010] Step 1: Use a cutting machine to cut the waste modified bitumen waterproof membrane to obtain the cutting material;

[0011] Step 2: The cut material from Step 1 is fed into a twin-screw extruder. After heating and shearing, the cut material is converted into molten recycled asphalt, realizing the recycling and reuse of waste modified asphalt waterproof membrane. The recycled asphalt contains base asphalt.

[0012] Furthermore, the cutting machine in step one is a laser cutting machine.

[0013] Furthermore, the waste modified bitumen waterproof membrane in step one is one or more of the following: non-compliant modified bitumen waterproof membrane, used or aged waterproof membrane, and scraps generated during the production or use of modified bitumen waterproof membrane.

[0014] Furthermore, the size of the material to be cut in step one is 1-5cm. 3 .

[0015] Furthermore, the cutting material comprises polyester fibers.

[0016] Furthermore, in step two, the twin-screw extruder contains a three-layer extrusion structure, which are arranged in the order of the material flow: the first extrusion structure, the second extrusion structure, and the third extrusion structure.

[0017] Furthermore, in step two, the block material is fed into the first feeding port of the first extrusion structure. The first extrusion structure is also equipped with a shearing element and a conveying element. The heating temperature of the first extrusion structure is 280-300℃, the screw length-to-diameter ratio is (10-20):1, and the rotation speed is 10-120rpm.

[0018] Furthermore, the recycled asphalt in step two also contains one or more substances selected from rubber modifiers, resin modifiers, inorganic fillers, and polyester fibers, wherein the polyester fibers include, but are not limited to, polyethylene terephthalate (PET).

[0019] The present invention also provides an application of the above-mentioned recycled asphalt, for example, for preparing recycled asphalt system modified asphalt or waterproof membrane containing recycled asphalt.

[0020] Furthermore, the preparation method of the modified asphalt from the recycled asphalt system includes the following steps:

[0021] Step 1: Intercalation modification of recycled asphalt extruded from a twin-screw extruder is performed using layered silicate clay to obtain layered silicate clay modified recycled asphalt.

[0022] Step 2: The layered silicate clay modified recycled asphalt obtained in Step 1 is melt-blended with biodegradable resin in a twin-screw extruder to obtain a recycled asphalt system modified asphalt. The softening point of the recycled asphalt system modified asphalt is 102-106℃, the low-temperature flexibility is -28.5-27.0℃, and the low-temperature flexibility decay temperature due to heat aging is 5.0-6.5℃.

[0023] Furthermore, the layered silicate clay in step one is one or a mixture of montmorillonite, bentonite, vermiculite, or attapulgite.

[0024] Furthermore, the particle size of the layered silicate clay in step one is 200-400 mesh.

[0025] Furthermore, in step one, the interlayer spacing of the layered silicate clay modified recycled bitumen is 0.9-3.5 nm.

[0026] Furthermore, the biodegradable resin in step two is one or more of polylactic acid (PLA), polyhydroxyalkanoate (PHA), polybutylene terephthalate (PBAT), polycaprolactone (PCL), polybutylene succinate (PBS), carbon dioxide copolymer (PPC), and polyglycolic acid (PGA).

[0027] Furthermore, the mass ratio of the recycled asphalt, layered silicate clay and biodegradable resin is (90-100):(5-10):(5-15).

[0028] Furthermore, the mass ratio of the recycled asphalt, layered silicate clay and biodegradable resin is (90-100):(7-10):(10-15).

[0029] Furthermore, the mass ratio of the recycled asphalt, layered silicate clay and biodegradable resin is (90-100):(9-10):(13-15).

[0030] Furthermore, the twin-screw extruder in steps one and two contains a three-layer extrusion structure, which are arranged sequentially according to the material flow as a first-layer extrusion structure, a second-layer extrusion structure, and a third-layer extrusion structure. A first connection port is provided between the first-layer and second-layer extrusion structures, and a second connection port is provided between the second-layer and third-layer extrusion structures. The second-layer extrusion structure also includes a second feed port, and the third-layer extrusion structure also includes a third feed port. All three extrusion structures are equipped with shearing elements and conveying elements.

[0031] The recycled asphalt is extruded from the first extrusion structure and conveyed to the second extrusion structure through the first connection port. It is then intercalated and modified with layered silicate clay entering from the second feeding port to obtain layered silicate clay modified recycled asphalt. The layered silicate clay modified recycled asphalt enters the third extrusion structure through the second connection port and is melt-blended and modified with biodegradable resin fed from the third feeding port to obtain a recycled asphalt system modified asphalt.

[0032] Furthermore, the heating temperature of the first extrusion structure is 280-300℃, the screw length-to-diameter ratio is (10-20):1, and the rotation speed is 10-120rpm.

[0033] Furthermore, the heating temperature of the second extrusion structure is 160-220℃, the screw length-to-diameter ratio is (10-20):1, the compression ratio is (2-5):1, and the rotation speed is 10-100rpm.

[0034] Furthermore, the heating temperature of the third extrusion structure is 100-160℃, the screw length-to-diameter ratio is (10-20):1, the compression ratio is (2-5):1, and the rotation speed is 10-100rpm.

[0035] The beneficial effects of this invention are as follows:

[0036] 1. The raw material selected for the recycled asphalt in this invention is waste modified asphalt waterproof membrane, especially waste modified asphalt waterproof membrane using polyester fiber. Compared with the simple heat treatment method of melting or melting waste modified asphalt waterproof membrane in the prior art, the recycling scheme of this invention can not only achieve the purpose of fully recycling waste modified asphalt waterproof membrane, but also produce usable recycled asphalt. The modified asphalt system prepared by recycled asphalt can also reduce the dependence on petrochemical synthetic compounds - artificial synthetic rubber required by traditional modified asphalt. At the same time, the preparation method of this invention also has the advantages of low energy consumption, low pollution, and reduced carbon dioxide emissions compared with the prior art.

[0037] 2. The present invention uses a laser cutter to cut waste modified asphalt waterproof membrane into recycled asphalt, instead of using a meshing crusher. This eliminates the problem that the meshing crusher breaks the waste modified asphalt membrane into pieces that stick together on a large scale, affecting its feeding into the twin-screw extruder.

[0038] 3. In preparing recycled asphalt and modified asphalt systems, this invention uses a specially designed twin-screw extruder. This extruder can convert waste modified asphalt waterproof membranes, especially those with polyester fibers as the reinforcing layer (primarily polyethylene terephthalate (PET),) into molten recycled asphalt in real time while isolating oxygen. This eliminates the high energy consumption, high pollution, and thermo-oxidative aging problems associated with the simple and crude process of boiling and recycling waste modified asphalt waterproof membranes. Furthermore, the prepared recycled asphalt can be used to prepare modified asphalt systems without changing equipment, offering advantages such as simplicity, high efficiency, reduced procedures, energy saving, and time saving.

[0039] 4. In preparing the modified asphalt system of the recycled asphalt system, the present invention uses biodegradable resin to replace petrochemical synthetic rubbers such as styrene-butadiene rubber and petroleum resin, thereby reducing dependence on petrochemical raw materials and reducing carbon emissions.

[0040] 5. In preparing the modified asphalt system of the present invention, layered silicate clay is used to intercalate and modify the recycled asphalt and biodegradable resin, which can effectively slow down the thermo-oxidative aging rate of small molecule rubber in the recycled asphalt and enhance the thermal stability and low-temperature brittleness of carbon dioxide-based resin. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the twin-screw extruder of the present invention.

[0042] The names of the labels in the diagram are as follows:

[0043] 1. First extrusion structure; 2. Second extrusion structure; 3. Third extrusion structure; 4. First feeding port; 5. Second feeding port; 6. Third feeding port; 7. First connecting port; 8. Second connecting port. Detailed Implementation

[0044] Example 1 Sample 1

[0045] This embodiment describes the preparation of recycled asphalt, including the following steps:

[0046] Step 1: Use a cutting machine to cut the waste modified bitumen waterproof membrane to obtain the cutting material;

[0047] Step 2: The block material from Step 1 is fed into a twin-screw extruder. After heating and shearing, the block material is transformed into a molten sample—recycled asphalt. The recycled asphalt contains base asphalt, thus realizing the recycling and reuse of waste modified asphalt waterproof membrane.

[0048] The cutting machine in step one is a laser cutting machine.

[0049] In step one, the waste modified bitumen waterproof membrane refers to non-compliant modified bitumen waterproof membrane, waterproof membrane that has been used or aged, and scraps generated during the production or use of modified bitumen waterproof membrane.

[0050] The size of the material to be cut in step one is 1-5 cm3.

[0051] The cutting material comprises polyester fibers, including but not limited to polyethylene terephthalate (PET).

[0052] like Figure 1 As shown, the twin-screw extruder in step two contains a three-layer extrusion structure, which are arranged in the following order according to the direction of the material: first extrusion structure 1, second extrusion structure 2, and third extrusion structure 3.

[0053] In step two, the cutting material is fed into the first feeding port 4 of the first extrusion structure 1. The first extrusion structure 1 is also equipped with a shearing element and a conveying element. The heating temperature of the first extrusion structure 1 is 300℃, the screw length-to-diameter ratio is 10:1, and the rotation speed is 80rpm.

[0054] Example 2 Sample 2

[0055] This embodiment illustrates the application of recycled asphalt from Sample 1 of Example 1, used to prepare a recycled asphalt system modified asphalt, and includes the following steps:

[0056] Step 1: Intercalation modification of the recycled asphalt extruded by the twin-screw extruder in Example 1 was carried out using layered silicate clay to obtain layered silicate clay modified recycled asphalt.

[0057] Step 2: The layered silicate clay modified recycled asphalt obtained in Step 1 is melt-blended with biodegradable resin in a twin-screw extruder to obtain Sample 2 recycled asphalt system modified asphalt.

[0058] In step one, the layered silicate clay is montmorillonite, the layered silicate clay-modified recycled bitumen is montmorillonite-modified recycled bitumen, and the particle size of the layered silicate clay is 200 mesh.

[0059] In step one, the interlayer spacing of the layered silicate clay modified recycled bitumen is 1.5 nm.

[0060] The biodegradable resin used in step two is polylactic acid (PLA), which was purchased from Zhejiang Hisun Pharmaceutical Co., Ltd. as REVODE 711 PLA.

[0061] The mass ratio of the recycled asphalt, layered silicate clay and biodegradable resin is 100:10:10.

[0062] like Figure 1 As shown, the twin-screw extruder in steps one and two contains a three-layer extrusion structure, which, in order of material flow, are a first extrusion structure 1, a second extrusion structure 2, and a third extrusion structure 3. A first connecting port 7 is provided between the first extrusion structure 1 and the second extrusion structure 2, and a second connecting port 8 is provided between the second extrusion structure 2 and the third extrusion structure 3. The second extrusion structure also includes a second feeding port 5, and the third extrusion structure 3 also includes a third feeding port 6. The first extrusion structure 1, the second extrusion structure 2, and the third extrusion structure 3 are all equipped with shearing elements and conveying elements.

[0063] The recycled asphalt is extruded from the first extrusion structure 1 and conveyed to the second extrusion structure 2 through the first connection port 7. It is then intercalated and modified with layered silicate clay entering from the second feeding port 5 to obtain layered silicate clay modified recycled asphalt. The layered silicate clay modified recycled asphalt enters the third extrusion structure 3 through the second connection port 8 and is melt-blended and modified with biodegradable resin fed from the third feeding port 6 to obtain modified asphalt of the recycled asphalt system.

[0064] The heating temperature of the first extrusion structure 1 is 300℃, the screw length-to-diameter ratio is 10:1, and the rotation speed is 80rpm.

[0065] The heating temperature of the second extrusion structure 2 is 180°C, the screw length-to-diameter ratio is 10:1, the compression ratio is 5:1, and the rotation speed is 60 rpm.

[0066] The heating temperature of the third extrusion structure 3 is 160℃, the screw length-to-diameter ratio is 10:1, the compression ratio is 5:1, and the rotation speed is 80rpm.

[0067] Example 3 Sample 3

[0068] This embodiment illustrates the application of recycled asphalt from Sample 1 of Example 1, used to prepare a recycled asphalt system modified asphalt, and includes the following steps:

[0069] Step 1: Intercalation modification of the recycled asphalt extruded by the twin-screw extruder in Example 1 was carried out using layered silicate clay to obtain layered silicate clay modified recycled asphalt.

[0070] Step 2: The layered silicate clay modified recycled asphalt obtained in Step 1 is melt-blended with biodegradable resin in a twin-screw extruder to obtain Sample 3 recycled asphalt system modified asphalt.

[0071] In step one, the layered silicate clay is montmorillonite, the layered silicate clay-modified recycled bitumen is montmorillonite-modified recycled bitumen, and the particle size of the layered silicate clay is 200 mesh.

[0072] In step one, the interlayer spacing of the layered silicate clay modified recycled bitumen is 1.5 nm.

[0073] In step two, the biodegradable resin is polylactic acid (PLA), which was purchased from Zhejiang Hisun Pharmaceutical Co., Ltd. as REVODE 701 PLA.

[0074] The mass ratio of the recycled asphalt, layered silicate clay and biodegradable resin is 100:10:10.

[0075] like Figure 1 As shown, the twin-screw extruder in steps one and two contains a three-layer extrusion structure, which, in order of material flow, are a first extrusion structure 1, a second extrusion structure 2, and a third extrusion structure 3. A first connecting port 7 is provided between the first extrusion structure 1 and the second extrusion structure 2, and a second connecting port 8 is provided between the second extrusion structure 2 and the third extrusion structure 3. The second extrusion structure also includes a second feeding port 5, and the third extrusion structure 3 also includes a third feeding port 6. The first extrusion structure 1, the second extrusion structure 2, and the third extrusion structure 3 are all equipped with shearing elements and conveying elements.

[0076] The recycled asphalt is extruded from the first extrusion structure 1 and conveyed to the second extrusion structure 2 through the first connection port 7. It is then intercalated and modified with layered silicate clay entering from the second feeding port 5 to obtain layered silicate clay modified recycled asphalt. The layered silicate clay modified recycled asphalt enters the third extrusion structure 3 through the second connection port 8 and is melt-blended and modified with biodegradable resin fed from the third feeding port 6 to obtain modified asphalt of the recycled asphalt system.

[0077] The heating temperature of the first extrusion structure 1 is 300℃, the screw length-to-diameter ratio is 10:1, and the rotation speed is 80rpm.

[0078] The heating temperature of the second extrusion structure 2 is 180°C, the screw length-to-diameter ratio is 10:1, the compression ratio is 5:1, and the rotation speed is 80 rpm.

[0079] The heating temperature of the third extrusion structure 3 is 160℃, the screw length-to-diameter ratio is 10:1, the compression ratio is 5:1, and the rotation speed is 80rpm.

[0080] Example 4 Sample 4

[0081] This embodiment illustrates the application of recycled asphalt from Sample 1 of Example 1, used to prepare a recycled asphalt system modified asphalt, and includes the following steps:

[0082] Step 1: Intercalation modification of the recycled asphalt extruded by the twin-screw extruder in Example 1 was carried out using layered silicate clay to obtain layered silicate clay modified recycled asphalt.

[0083] Step 2: The layered silicate clay modified recycled asphalt obtained in Step 1 is melt-blended with biodegradable resin in a twin-screw extruder to obtain Sample 4, a recycled asphalt system modified asphalt.

[0084] In step one, the layered silicate clay is montmorillonite, the layered silicate clay-modified recycled bitumen is montmorillonite-modified recycled bitumen, and the particle size of the layered silicate clay is 200 mesh.

[0085] In step one, the interlayer spacing of the layered silicate clay modified recycled bitumen is 1.5 nm.

[0086] The biodegradable resin used in step two is polylactic acid (PLA), which was purchased from Zhejiang Hisun Pharmaceutical Co., Ltd. as REVODE 711 PLA.

[0087] The mass ratio of the recycled asphalt, layered silicate clay and biodegradable resin is 100:10:15.

[0088] like Figure 1As shown, the twin-screw extruder in steps one and two contains a three-layer extrusion structure, which, in order of material flow, are a first extrusion structure 1, a second extrusion structure 2, and a third extrusion structure 3. A first connecting port 7 is provided between the first extrusion structure 1 and the second extrusion structure 2, and a second connecting port 8 is provided between the second extrusion structure 2 and the third extrusion structure 3. The second extrusion structure 2 also includes a second feeding port 5, and the third extrusion structure 3 also includes a third feeding port 6. The first extrusion structure 1, the second extrusion structure 2, and the third extrusion structure 3 are all equipped with shearing elements and conveying elements.

[0089] The recycled asphalt is extruded from the first extrusion structure 1 and conveyed to the second extrusion structure 2 through the first connection port 7. It is then intercalated and modified with layered silicate clay entering from the second feeding port 5 to obtain layered silicate clay modified recycled asphalt. The layered silicate clay modified recycled asphalt enters the third extrusion structure 3 through the second connection port 8 and is melt-blended and modified with biodegradable resin fed from the third feeding port 6 to obtain modified asphalt of the recycled asphalt system.

[0090] The heating temperature of the first extrusion structure 1 is 300℃, the screw length-to-diameter ratio is 10:1, and the rotation speed is 80rpm.

[0091] The heating temperature of the second extrusion structure 2 is 180°C, the screw length-to-diameter ratio is 10:1, the compression ratio is 5:1, and the rotation speed is 60 rpm.

[0092] The heating temperature of the third extrusion structure 3 is 160℃, the screw length-to-diameter ratio is 10:1, the compression ratio is 5:1, and the rotation speed is 80rpm.

[0093] Comparative Example 1 Sample 5

[0094] In this comparative example, petroleum asphalt was used to replace the recycled asphalt in Example 2. Modified asphalt was prepared using the twin-screw extruder provided by this invention. The specific steps are as follows:

[0095] Step 1: Intercalation modification of petroleum asphalt using layered silicate clay to obtain layered silicate clay modified petroleum asphalt;

[0096] Step 2: The layered silicate clay modified petroleum asphalt obtained in Step 1 is melt-blended with biodegradable resin in a twin-screw extruder to obtain the petroleum asphalt system modified asphalt of Sample 5.

[0097] In step one, the petroleum asphalt is 70# or 90# petroleum asphalt.

[0098] In step one, the layered silicate clay is montmorillonite, the layered silicate clay-modified petroleum asphalt is montmorillonite-modified petroleum asphalt, and the particle size of the layered silicate clay is 200 mesh.

[0099] In step one, the interlayer spacing of the layered silicate clay modified petroleum asphalt is 1.5 nm.

[0100] The biodegradable resin used in step two is polylactic acid (PLA), which was purchased from Zhejiang Hisun Pharmaceutical Co., Ltd. as REVODE 711 PLA.

[0101] The mass ratio of the petroleum asphalt, layered silicate clay, and biodegradable resin is 100:10:10.

[0102] like Figure 1 As shown, the twin-screw extruder in steps one and two contains a three-layer extrusion structure, which, in order of material flow, are a first extrusion structure 1, a second extrusion structure 2, and a third extrusion structure 3. A first connecting port 7 is provided between the first extrusion structure 1 and the second extrusion structure 2, and a second connecting port 8 is provided between the second extrusion structure 2 and the third extrusion structure 3. The second extrusion structure 2 also includes a second feeding port 5, and the third extrusion structure 3 also includes a third feeding port 6. The first extrusion structure 1, the second extrusion structure 2, and the third extrusion structure 3 are all equipped with shearing elements and conveying elements.

[0103] In this process, the petroleum asphalt and layered silicate clay enter the extruder through the second feed port 5 of the second extrusion structure 2 for intercalation modification, thereby obtaining layered silicate clay-modified petroleum asphalt. The layered silicate clay-modified petroleum asphalt then enters the third extrusion structure 3 through the second connection port 8, where it is melt-blended and modified with biodegradable resin fed through the third feed port 6, thereby obtaining petroleum asphalt system modified asphalt.

[0104] The heating temperature of the second extrusion structure 2 is 180°C, the screw length-to-diameter ratio is 10:1, the compression ratio is 5:1, and the rotation speed is 60 rpm.

[0105] The heating temperature of the third extrusion structure 3 is 160℃, the screw length-to-diameter ratio is 10:1, the compression ratio is 5:1, and the rotation speed is 80rpm.

[0106] The performance of the samples from Examples 2-4 and Comparative Example 1 was tested, and the test results are shown in Table 1:

[0107] Table 1

[0108]

[0109] The test method for the retention rate of tensile elongation at break of photodegradable modified asphalt shall be performed in accordance with 5.3 of GB / T 20197-2006 "Definition, Classification, Marking and Degradation Performance Requirements of Degradable Plastics" and Type II specimens in GB / T 1040 "Test Method for Tensile Properties of Plastics", without distinguishing between transverse and longitudinal directions.

[0110] In summary, the recycled asphalt system produced by this invention, using a specially designed twin-screw extruder to prepare modified asphalt from recycled waste modified asphalt waterproof membrane, exhibits a higher softening point, lower low-temperature flexibility, lower thermal aging low-temperature flexibility decay temperature, and lower retention rate of tensile elongation at break compared to petroleum asphalt system modified asphalt prepared using a twin-screw extruder. This invention, through the combined use of a specially designed twin-screw extruder and the preparation method of the recycled asphalt system modified asphalt, eliminates the high energy consumption, high pollution, and thermo-oxidative aging problems associated with the simple and crude process of boiling and recycling waste modified asphalt waterproof membrane. Furthermore, the prepared recycled asphalt system modified asphalt can be produced without changing equipment, offering advantages such as simplicity, high efficiency, simplified procedures, energy saving, and time reduction.

[0111] It should be understood that the present invention is not limited to the content and structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for preparing modified asphalt using a recycled asphalt system, characterized in that, Includes the following steps: Step 1: Use a cutting machine to cut the waste modified bitumen waterproof membrane to obtain the cutting material; Step 2: The cut material from Step 1 is fed into a twin-screw extruder. After heating and shearing, the cut material is converted into molten recycled asphalt, thereby realizing the recycling and reuse of waste modified asphalt waterproof membrane. The recycled asphalt contains base asphalt. Step 3: Intercalation modification of recycled asphalt extruded from a twin-screw extruder is performed using layered silicate clay to obtain layered silicate clay modified recycled asphalt; Step 4: The layered silicate clay modified recycled asphalt obtained in Step 3 is melt-blended with biodegradable resin in a twin-screw extruder to obtain a recycled asphalt system modified asphalt. The softening point of the recycled asphalt system modified asphalt is 102-106℃, the low-temperature flexibility is -28.5-27.0℃, and the thermal aging low-temperature flexibility decay temperature is 5.0-6.5℃.

2. The method for preparing modified asphalt using the recycled asphalt system according to claim 1, characterized in that, The cutting machine in step one is a laser cutting machine.

3. The method for preparing modified asphalt using the recycled asphalt system according to claim 1, characterized in that, In step one, the waste modified bitumen waterproof membrane refers to one or more of the following: non-compliant modified bitumen waterproof membrane, used or aged waterproof membrane, and scraps generated during the production or use of modified bitumen waterproof membrane.

4. The method for preparing modified asphalt using the recycled asphalt system according to claim 1, characterized in that, The size of the material to be cut in step one is 1-5cm. 3 .

5. The method for preparing modified asphalt using the recycled asphalt system according to claim 4, characterized in that, The cutting material contains polyester fiber.

6. The method for preparing modified asphalt using the recycled asphalt system according to claim 1, characterized in that, In step two, the twin-screw extruder contains a three-layer extrusion structure, which is arranged in the order of the material flow: the first extrusion structure, the second extrusion structure, and the third extrusion structure.

7. The method for preparing modified asphalt using the recycled asphalt system according to claim 6, characterized in that, In step two, the cutting material is fed into the first feeding port of the first extrusion structure. The first extrusion structure is also equipped with a shearing element and a conveying element. The heating temperature of the first extrusion structure is 280-300℃, the screw length-to-diameter ratio is (10-20):1, and the rotation speed is 10-120rpm.

8. The method for preparing modified asphalt using the recycled asphalt system according to claim 1, characterized in that, The recycled asphalt in step two also contains one or more substances selected from rubber modifiers, resin modifiers, inorganic fillers, and polyester fibers.

9. The method for preparing modified asphalt using the recycled asphalt system according to claim 1, characterized in that, In step three, the layered silicate clay is one or more of montmorillonite, bentonite, vermiculite, or attapulgite, or the particle size of the layered silicate clay is 200-400 mesh.

10. The method for preparing modified asphalt using the recycled asphalt system according to claim 1, characterized in that, In step three, the interlayer spacing of the layered silicate clay modified recycled bitumen is 0.9-3.5 nm.

11. The method for preparing modified asphalt using the recycled asphalt system according to claim 1, characterized in that, The biodegradable resin in step four is one or more of polylactic acid, polyhydroxyalkanoate, polybutylene terephthalate-adipate, polycaprolactone, polybutylene succinate, carbon dioxide copolymer, and polyglycolic acid.

12. The method for preparing modified asphalt using the recycled asphalt system according to claim 1, characterized in that, The mass ratio of the recycled asphalt, layered silicate clay and biodegradable resin is (90-100):(5-10):(5-15).

13. The method for preparing modified asphalt using the recycled asphalt system according to claim 1, characterized in that, The twin-screw extruder in steps three and four contains a three-layer extrusion structure, which, in order of material flow, are the first, second, and third extrusion layers. A first connection port is provided between the first and second extrusion layers, and a second connection port is provided between the second and third extrusion layers. The second extrusion layer also includes a second feed port, and the third extrusion layer also includes a third feed port. All three extrusion layers are equipped with shearing and conveying elements. The recycled asphalt is extruded from the first extrusion structure and conveyed to the second extrusion structure through the first connection port. It is then intercalated and modified with layered silicate clay entering from the second feeding port to obtain layered silicate clay modified recycled asphalt. The layered silicate clay modified recycled asphalt enters the third extrusion structure through the second connection port and is melt-blended and modified with biodegradable resin fed from the third feeding port to obtain a recycled asphalt system modified asphalt.

14. The method for preparing modified asphalt using the recycled asphalt system according to claim 13, characterized in that, The heating temperature of the first extrusion structure is 280-300℃, the screw length-to-diameter ratio is (10-20):1, and the rotation speed is 10-120 rpm; or the heating temperature of the second extrusion structure is 160-220℃, the screw length-to-diameter ratio is (10-20):1, the compression ratio is (2-5):1, and the rotation speed is 10-100 rpm; or the heating temperature of the third extrusion structure is 100-160℃, the screw length-to-diameter ratio is (10-20):1, the compression ratio is (2-5):1, and the rotation speed is 10-100 rpm.

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