Pouring type asphalt modifier and processing method thereof

Abstract

The invention provides a pouring type asphalt modifier and a processing method thereof, and the method comprises the following steps: mixing high-softening-point natural asphalt and softening oil in proportion by a high-speed mixer, and mixing and extruding at high temperature by a screw extruder to form pouring type asphalt modifier solid particles; the softening temperature of the high-softening-point natural asphalt is 180 DEG C or above; the mass ratio of the high-softening-point natural asphalt to the softening oil is (70-85): (15-30); the rotating speed of the high-speed mixer is more than 60 revolutions per minute; the high-temperature mixing temperature of the screw extruder is 230 to 260 DEG C. The obtained pouring type asphalt modifier can reduce the processing temperature of pouring type asphalt and improve the dissolution and dispersion speed of natural asphalt at the same time. In addition, the solid particle modifier is formed through a new processing method, and dust pollution and the like in the processing process are reduced.

Description

Technical Field

[0001] The invention belongs to the field of raw material modifier for type III pouring asphalt for bridge deck pavement and its processing, and in particular relates to a pouring asphalt modifier and its processing method. Background Art

[0002] Casting asphalt is an asphalt material used for bridge deck paving casting asphalt mixture, of which type III casting asphalt is a composite modified asphalt of petroleum asphalt and natural asphalt. Petroleum asphalt is a product obtained from the crude oil processing process. It is a black or dark brown viscous liquid or solid at room temperature, mainly containing hydrocarbons and non-hydrocarbon derivatives soluble in trichloroethylene. Natural asphalt is mostly rock asphalt, and its softening point is generally greater than 180℃.

[0003] When processing poured asphalt, the temperature required to dissolve natural asphalt usually exceeds the normal asphalt processing temperature by more than 20°C; high temperature will cause the aging of petroleum asphalt, which can easily reduce the ductility and other indicators of poured asphalt. In addition, natural rock asphalt is mostly very fine powder, which is easy to form dust during processing, which is not good for operators, the environment and safety. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a cast asphalt modifier and a processing method thereof. The cast asphalt modifier obtained by the method of the present invention can reduce the processing temperature of cast asphalt, while increasing the dissolution and dispersion speed of natural asphalt, and solve the dust pollution of powdered natural asphalt during processing.

[0005] The present invention provides a method for processing a pourable asphalt modifier, which comprises the following steps:

[0006] The high softening point natural asphalt and softening oil are mixed in proportion through a high-speed mixer, and then mixed and extruded at high temperature through a screw extruder to form pourable asphalt modifier solid particles;

[0007] The softening temperature of the high-softening-point natural asphalt is above 180°C; the mass ratio of the high-softening-point natural asphalt to softening oil is 70-85:15-30; the rotation speed of the high-speed mixer is above 60 rpm; the high-temperature mixing temperature of the screw extruder is 230-260°C.

[0008] In an embodiment of the present invention, the high softening point natural asphalt is rock asphalt with an ash content of ≤5%.

[0009] In an embodiment of the present invention, the softening oil is aromatic oil and / or naphthenic oil. Further, the flash point of the softening oil is ≥200°C, and the kinematic viscosity at 100°C is 25-60mm 2 / s.

[0010] In an embodiment of the present invention, the mixing time of the high-speed mixer is more than 10 minutes.

[0011] In an embodiment of the present invention, the rotation speed of the screw extruder is above 60 revolutions per minute, and the extruder is cooled after extrusion to form castable asphalt modifier solid particles.

[0012] In an embodiment of the present invention, the feeding section of the screw extruder is not heated. Further, the screw diameter of the screw extruder is 20-150 mm, the screw aspect ratio is 10:1-60:1, and the compression ratio is 2:1-4:1.

[0013] The present invention provides a pourable asphalt modifier obtained by the processing method as described above, which is a solid particle with a softening point below 140°C.

[0014] In an embodiment of the present invention, the softening point of the cast asphalt modifier is above 110° C. and the ash content is less than 15%.

[0015] Compared with the prior art, the present invention provides a pouring asphalt modifier and a processing method thereof, which can form solid particles of the pouring asphalt modifier by mixing high-softening point natural asphalt (softening point ≥ 180°C) and softening oil in a certain mass ratio through a high-speed mixer and high-temperature mixing and extrusion by a screw extruder, and cooling. The obtained pouring asphalt modifier can reduce the pouring asphalt processing temperature and improve the dissolution and dispersion speed of natural asphalt. In addition, the present invention forms a solid particle modifier through a new processing method, which reduces dust pollution and the like during the processing process.

[0016] Furthermore, the softening point of the pourable asphalt modifier described in the embodiment of the present invention is between 110°C and 140°C, which can ensure that the modifier will not produce sticky blocks during long-distance transportation and long-term stacking and storage, thereby affecting the feeding and melting dispersion. It can also reduce the softening point of natural asphalt, achieve rapid dissolution of rock asphalt under lower temperature conditions, and reduce the risk of asphalt aging caused by high-temperature and long-term processing. DETAILED DESCRIPTION

[0017] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the technical scheme of the present invention is now described in detail below in conjunction with specific embodiments. The described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0018] The present invention provides a method for processing a pourable asphalt modifier, which comprises the following steps:

[0019] The high softening point natural asphalt and softening oil are mixed in proportion through a high-speed mixer, and then mixed and extruded at high temperature through a screw extruder to form pourable asphalt modifier solid particles;

[0020] The softening temperature of the high-softening-point natural asphalt is above 180°C; the mass ratio of the high-softening-point natural asphalt to softening oil is 70-85:15-30; the rotation speed of the high-speed mixer is above 60 rpm; the high-temperature mixing temperature of the screw extruder is 230-260°C.

[0021] The cast asphalt modifier obtained by the method of the present invention can reduce the processing temperature of the cast asphalt, while increasing the dissolution and dispersion speed of natural asphalt, and solving the dust pollution of powdered natural asphalt during processing.

[0022] In the embodiment of the present invention, the high-softening-point natural asphalt and the softening oil are weighed according to a certain mass ratio, and then mixed in a high-speed mixer to obtain a mixture.

[0023] In the embodiments of the present application, the high softening point natural asphalt is a rock asphalt with a softening point ≥ 180°C, for example, 190°C to 300°C or 190 to 250°C, and an ash mass content ≤ 15% (preferably ash content between 4 and 15%). According to the different formation environments, natural asphalt can be divided into rock asphalt, lake asphalt, seabed asphalt, etc.; rock asphalt is an asphalt-like substance formed by long-term evaporation and solidification of petroleum that continuously emerges from the earth's crust and exists in mountains and rock cracks. The softening point of asphalt is generally the temperature at which the asphalt specimen softens and sags due to heat; the embodiments of the present invention are not limited to rock asphalt, but also include lake asphalt, etc.

[0024] Preferably, the softening oil has a kinematic viscosity of 25-60 mm at 100 °C. 2 / s, aromatic oil, naphthenic oil, reduced oil, engine oil, etc. with a flash point ≥ 200°C. Specifically, the softened oil is reduced oil produced by atmospheric and vacuum processing of petroleum, with a kinematic viscosity of 30mm at 100°C. 2 / s, flash point 205℃.

[0025] The mass ratio of the high softening point natural asphalt and the lubricating oil mixed in the embodiment of the present invention is high softening point natural asphalt: softening oil = 70%:30% to 85%:15%, which can make the asphalt softening point ≥110°C and ≤140°C, and the ash content <15%; this is conducive to ensuring transportation and storage, as well as subsequent applications. In some embodiments, the mass ratio of high softening point natural asphalt to softening oil is 70%:30%, 73%:27%, 75%:25%, 80%:20%, 82%:18%, or 85%:15%, etc.

[0026] In an embodiment of the present application, the processing method comprises: firstly, adding high softening point natural asphalt and softening oil into a high-speed mixer (referred to as high-speed mixer, conventional equipment) according to a certain mass ratio, stirring at a speed of >60 rpm, mixing time >10 min, and mixing uniformly. The speed of the high-speed mixer can be 65-150 rpm, and the mixing time is, for example, 15-30 minutes.

[0027] In the embodiment of the present invention, the obtained mixed material is added to a screw extruder, mixed at high temperature, extruded, and cooled to form castable asphalt modifier solid particles. The screw extruder is a cold feed type, that is, its feeding section is not heated. The cold feed screw extruder can feed the mixed material, and through the effects of screw extrusion, shearing and stirring, the materials are mixed, heated and formed, and continuously extruded from the die; it is mainly composed of a screw, a barrel, a die head, a feeding mechanism, a transmission device, and a temperature control system.

[0028] In the embodiment of the present invention, the processing can be carried out according to the screw speed>60 rpm, the feeding end of the extruder is not heated, and the temperature of the compression section and the metering section is 230-260°C. The screw speed is further 70-100 rpm, etc.; the compression section is mainly used to compact the material, and the temperature of the high-temperature mixing can be 240-255°C.

[0029] Preferably, the screw diameter of the screw extruder is 20-150 mm, further 30-200 mm, the screw aspect ratio is 10:1-60:1, preferably 20:1-50:1, further 30:1-40:1, and the compression ratio can be 2:1-4:1, which is conducive to ensuring the index performance of the asphalt modifier. The compression ratio is the ratio of the volume of one screw groove of the feeding section of the screw to the volume of the last screw groove of the homogenization section.

[0030] The solid granular asphalt modifier obtained by the above method and process in the embodiment of the present invention is advantageously applied to cast asphalt materials. That is, the present invention provides a cast asphalt modifier obtained by the above processing method, which is a solid particle; the cast asphalt modifier has a softening point below 140°C and above 110°C.

[0031] In an embodiment of the present invention, the softening point of the cast asphalt modifier is ≥110° C. and ≤140° C., and the ash content is <15%, for example, the ash content is 1-13%, and further 2-12%.

[0032] During the pouring asphalt processing, the pouring asphalt modifier described in the embodiment of the present invention can be dissolved and blended in 50# road asphalt at 170°C, which is more than 20°C lower than the processing temperature of natural asphalt directly put into 50# road asphalt; at the same time, there is no dust during the processing, and the processing is environmentally friendly and safe. The processing method described in the present invention is simple and low in cost.

[0033] In order to further understand the present invention, the present invention is described in detail below in conjunction with the examples, and the protection scope of the present invention is not limited by the following examples. In the examples, all raw reagents and materials are commercially available, and the experimental methods without specific experimental conditions are conventional methods and conditions well known in the art.

[0034] The rock asphalt used in the following embodiments of the present invention includes Iranian rock asphalt, North American rock asphalt, and Xinjiang rock asphalt. The softening point of Iranian rock asphalt is 190°C, and the ash content is 15%. The softening point of North American rock asphalt is 210°C, and the ash content is 4%. The softening point of Xinjiang rock asphalt is 200°C, and the ash content is 5%. The softening oil used is the reduced line oil produced by petroleum atmospheric and vacuum processing, and the kinematic viscosity at 100°C is 30mm 2 / s, flash point 205 ° C. The screw extruder used has a diameter of 35 mm, an aspect ratio of 40:1, and a compression ratio of 2:1 (other parameters of the extruder: maximum speed 500 rad / min, motor power 18.5KW, and production capacity 20-50kg / h).

[0035] Example 1

[0036] Iranian natural asphalt and softened oil were weighed in a mass ratio of 80%:20%, mixed in a high-speed mixer at 100 rpm for 20 minutes. The mixture was added to an extruder for extrusion at a speed of 100 rpm, the feed end was not heated, and the temperature of the compression section and the metering section was 240°C. The produced cast asphalt modifier was solid particles (particle size of about 2-4mm), with a softening point of 110°C and an ash content of 12%.

[0037] During the pouring asphalt processing, the pouring asphalt modifier of the present invention can be dissolved and blended in 50# road asphalt at 170°C, which is more than 20°C lower than the processing temperature of natural asphalt directly put into 50# road asphalt; at the same time, there is no dust in the processing process, and the processing is environmentally friendly and the safety is improved.

[0038] In addition, the pouring asphalt ductility and other indicators meet the technical requirements of Type III of "JT / T 1131.4-2023 Steel Bridge Deck Pavement Part 4: Poured Asphalt". Among them, the amount of modifier added is 15% of the low-grade asphalt; the pouring asphalt ductility is 14cm.

[0039] Example 2

[0040] The North American rock asphalt and softening oil were weighed in a mass ratio of 73%:27%, mixed in a high-speed mixer at 100 rpm for 20 minutes. The mixture was added to the extruder for extrusion, the extruder speed was 100 rpm, the feeding end was not heated, and the temperature of the compression section and the metering section was 240°C. The produced cast asphalt modifier had a softening point of 120°C and an ash content of 3%.

[0041] During the pouring asphalt processing, the pouring asphalt modifier of the present invention can be dissolved and blended in 50# road asphalt at 170°C, which is more than 20°C lower than the processing temperature of natural asphalt directly put into 50# road asphalt; at the same time, there is no dust during the processing, and the processing is environmentally friendly and safe. Among them, the amount of modifier added is 14% of the low-grade asphalt; the ductility of the pouring asphalt is 12cm.

[0042] Example 3

[0043] Xinjiang rock asphalt and softening oil were weighed in a mass ratio of 75%:25% and mixed in a high-speed mixer at 100 rpm for 20 minutes. The mixture was added to the extruder for extrusion at a speed of 100 rpm. The feed end was not heated, and the temperature of the compression section and the metering section was 240°C. The softening point of the cast asphalt modifier produced was 115°C and the ash content was 4%.

[0044] During the pouring asphalt processing, the pouring asphalt modifier of the present invention can be dissolved and blended in 50# road asphalt at 170°C, which is more than 20°C lower than the processing temperature of natural asphalt directly put into 50# road asphalt; at the same time, there is no dust during the processing, and the processing is environmentally friendly and safe. Among them, the amount of modifier added is 14% of the low-grade asphalt; the ductility of the pouring asphalt is 12cm.

[0045] It can be seen from the above embodiments that the cast asphalt modifier obtained by the present invention can reduce the processing temperature of cast asphalt and improve the dissolution and dispersion speed of natural asphalt. In addition, the present invention forms a solid particle modifier through a new processing method, which reduces dust pollution in the processing process. Furthermore, the softening point of the cast asphalt modifier described in the embodiment of the present invention is between 110°C and 140°C, which can ensure that the modifier will not produce sticky blocks during long-distance transportation and long-term stacking and storage, thereby affecting feeding and melting and dispersion. It can also reduce the softening point of natural asphalt, achieve rapid dissolution of rock asphalt under lower temperature conditions, and reduce the risk of asphalt aging caused by high-temperature and long-term processing.

[0046] The embodiments of the present invention are merely examples for clearly explaining the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all implementation methods here, and these obvious changes or modifications derived from the spirit of the present invention are still within the scope of protection of the present invention.

[0047] The above is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for processing a cast asphalt modifier, characterized in that: The following steps are involved: The high softening point natural asphalt and softening oil are mixed in proportion through a high-speed mixer, and then mixed and extruded at high temperature through a screw extruder to form pourable asphalt modifier solid particles; The softening temperature of the high-softening-point natural asphalt is above 180°C; the mass ratio of the high-softening-point natural asphalt to softening oil is 70-85:15-30; the rotation speed of the high-speed mixer is above 60 rpm; the high-temperature mixing temperature of the screw extruder is 230-260°C.

2. The processing method according to claim 1, characterized in that: The high softening point natural asphalt is rock asphalt with an ash content of ≤5%.

3. The processing method according to claim 1, characterized in that: The softening oil is aromatic oil and / or naphthenic oil.

4. The processing method according to claim 3, characterized in that: The flash point of the softening oil is ≥200°C, and the kinematic viscosity at 100°C is 25-60mm 2 / s.

5. The processing method according to any one of claims 1 to 4, characterized in that: The mixing time of the high-speed mixer is more than 10 minutes.

6. The processing method according to any one of claims 1 to 4, characterized in that: The rotation speed of the screw extruder is above 60 revolutions per minute, and the solid particles of the castable asphalt modifier are formed by cooling after extrusion.

7. The processing method according to claim 6, characterized in that: The feed section of the screw extruder is not heated.

8. The processing method according to claim 7, characterized in that: The screw extruder has a screw diameter of 20-150 mm, a screw length-to-diameter ratio of 10:1-60:1, and a compression ratio of 2:1-4:

1.

9. The cast asphalt modifier obtained by the processing method according to any one of claims 1 to 8, which is a solid particle with a softening point below 140°C.

10. The pourable asphalt modifier according to claim 9, characterized in that: The softening point of the pourable asphalt modifier is above 110° C. and the ash content is less than 15%.