A cast asphalt modifier and method of processing the same

Abstract

The application provides a casting asphalt modifier and a processing method thereof, which comprises the following steps: mixing high-softening-point natural asphalt and softening oil in proportion through a high-speed mixer, and mixing and extruding the high-softening-point natural asphalt and the softening oil through a screw extruder at high temperature to form solid particles of the casting asphalt modifier; the softening temperature of the high-softening-point natural asphalt is above 180 DEG C; 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 above 60 r / min; and the temperature of high-temperature mixing of the screw extruder is 230-260 DEG C. The obtained casting asphalt modifier can reduce the processing temperature of the casting asphalt and improve the dissolution and dispersion speed of the natural asphalt. In addition, the solid particle modifier is formed through a new processing method, and dust pollution and the like in the processing process is reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of raw material modifier for bridge deck pavement type III paving asphalt and its processing, and particularly relates to a paving asphalt modifier and a processing method thereof. BACKGROUND

[0002] Paving asphalt is an asphalt material for bridge deck pavement paving asphalt mixture, and type III paving asphalt is a petroleum asphalt and natural asphalt composite modified asphalt. Petroleum asphalt is a product obtained in the process of crude oil processing, which is a black or black-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 paving asphalt, it is usually necessary to dissolve natural asphalt at a temperature of more than 20℃ higher than the conventional asphalt processing temperature; and high temperature can cause aging of petroleum asphalt, which can easily reduce the elongation of paving asphalt and other indicators. In addition, natural rock asphalt is mostly fine powder, which is easy to form dust during processing, which is not conducive to the operators and the environment and safety. SUMMARY

[0004] Therefore, the purpose of the present application is to provide a paving asphalt modifier and a processing method thereof. The paving asphalt modifier processed by the method can reduce the processing temperature of paving asphalt, improve the dissolution and dispersion speed of natural asphalt, and solve the dust pollution of powdered natural asphalt during processing.

[0005] The present application provides a processing method of a paving asphalt modifier, which comprises the following steps:

[0006] mixing high softening point natural asphalt and softening oil in proportion through a high-speed mixer, and mixing and extruding through a screw extruder at high temperature to form solid particles of the paving asphalt modifier;

[0007] The softening temperature of the high softening point natural asphalt is above 180℃; the mass ratio of the high softening point natural asphalt and the softening oil is 70-85:15-30; the rotating speed of the high-speed mixer is above 60 revolutions per minute; and the temperature of high temperature mixing of the screw extruder is 230-260℃.

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

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

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

[0011] In the embodiment of the present application, the rotating speed of the screw extruder is more than 60 rpm, and the extruded product is cooled to form the solid particles of the paving asphalt modifier.

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

[0013] The present application provides the solid particles of the paving asphalt modifier obtained by the processing method as described above, which has a softening point of less than 140℃.

[0014] In the embodiment of the present application, the softening point of the paving asphalt modifier is more than 110℃, and the ash content is less than 15%.

[0015] Compared with the prior art, the present application provides a paving asphalt modifier and a processing method thereof, which can mix high-softening-point natural asphalt (softening point ≥180℃) and softening oil at a certain mass ratio, uniformly mix the mixture by a high-speed mixer, and then mix and extrude the mixture by a screw extruder at high temperature to form solid particles of the paving asphalt modifier. The obtained paving asphalt modifier can reduce the processing temperature of the paving asphalt, and improve the dissolution and dispersion speed of the natural asphalt. Further, the present application forms the solid particles of the modifier by a new processing method, which reduces the dust pollution in the processing process.

[0016] Further, the softening point of the paving asphalt modifier according to the embodiment of the present application is between 110℃ and 140℃, which can ensure that the modifier will not stick and form agglomerates during long-distance transportation and long-time storage, and thus affect the feeding and melting dispersion. The softening point of the natural asphalt can be reduced, the rock asphalt can be quickly dissolved at a lower temperature, and the risk of asphalt aging caused by long-time processing at high temperature can be reduced. DETAILED DESCRIPTION

[0017] In order to more clearly understand the technical features, objectives and effects of the present application, the technical solutions of the present application will be described in detail below in combination with specific embodiments. The described embodiments are only some of the embodiments of the present application, but not all the embodiments.

[0018] The present application provides a processing method of a paving asphalt modifier, which comprises the following steps:

[0019] mixing high-softening-point natural asphalt and softening oil by a high-speed mixer, and then mixing and extruding the mixture by a screw extruder at high temperature to form solid particles of the paving asphalt modifier;

[0020] The softening temperature of the high softening point natural asphalt is above 180℃; the mass ratio of the high softening point natural asphalt and the softening oil is 70-85:15-30; the rotating speed of the high-speed mixer is above 60 revolutions per minute; and the temperature of the high-temperature mixing of the screw extruder is 230-260℃.

[0021] The casting asphalt modifier processed by the method can reduce the processing temperature of the casting asphalt, improve the dissolution and dispersion speed of the natural asphalt, and solve the dust pollution of the powder natural asphalt during processing.

[0022] In the embodiments of the present application, 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 rock asphalt with a softening point ≥180℃, for example, 190-300℃ or 190-250℃, and an ash content ≤15% (preferably, the ash content is between 4-15%). According to different environments, the natural asphalt can be divided into rock asphalt, lake asphalt, seabed asphalt, etc. The rock asphalt is a kind of asphalt-like substance formed by the continuous emergence of petroleum from the earth's crust, existing in the cracks of mountains and rocks, and long-term evaporation and condensation. The softening point of asphalt is generally the temperature at which the asphalt test piece softens and droops under heat; the embodiments of the present application are not limited to rock asphalt, but also include lake asphalt, etc.

[0024] As a preferred, the softening oil has a kinematic viscosity of 25-60mm 2 / s at 100℃, a flash point ≥200℃, and is aromatic oil, naphthenic oil, cutting oil, engine oil, etc. Specifically, the softening oil is cutting oil produced by petroleum atmospheric and vacuum distillation, has a kinematic viscosity of 30mm 2 / s at 100℃, and a flash point of 205℃.

[0025] The mass ratio of the high softening point natural asphalt and the softening oil in the embodiments of the present application is 70%:30% to 85%:15%, which can make the softening point of the asphalt ≥110℃ and ≤140℃, and the ash content <15%, so as to facilitate the transportation and storage, and subsequent application. In some embodiments, the mass ratio of the high softening point natural asphalt and the softening oil is 70%:30%, 73%:27%, 75%:25%, 80%:20%, 82%:18%, or 85%:15%, etc.

[0026] In the embodiments 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 > 60 rpm, and mixing for > 10 min, until the mixture is uniformly mixed. The speed of the high-speed mixer can be 65-150 rpm, and the mixing time can be, for example, 15-30 min.

[0027] In the embodiments of the present application, the obtained mixture is added into a screw extruder for high-temperature mixing and extrusion, and then cooled to form solid particles of the casting asphalt modifier. The screw extruder is in a cold feeding mode, i.e., the feeding section is not heated. The cold feeding screw extruder can feed the mixture, and through the actions of extrusion, shearing and stirring of the screw, the material is mixed and heated to be shaped, and then continuously extruded from the die. The screw extruder mainly comprises a screw, a barrel, a head, a feeding mechanism, a transmission device and a temperature control system.

[0028] In the embodiments of the present application, the processing can be performed at a 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℃. The screw speed can be further 70-100 rpm, etc. The compression section mainly serves to compact the material, and the temperature of high-temperature mixing can be 240-255℃.

[0029] As preferred, the screw diameter of the screw extruder is 20-150 mm, further 30-200 mm, the length-diameter ratio of the screw 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 beneficial to guarantee the index performance of the asphalt modifier. The compression ratio is the ratio of the volume of one screw groove in the feeding section to the volume of the last screw groove in the homogenizing section.

[0030] The solid particulate asphalt modifier obtained by the above-mentioned method and process in the embodiments of the present application is beneficial to be applied in the casting asphalt material. That is, the present application provides the casting asphalt modifier obtained by the above-mentioned processing method, which is a solid particle; the softening point of the casting asphalt modifier is below 140℃ and above 110℃.

[0031] In the embodiments of the present application, the softening point of the casting asphalt modifier is ≥110℃ and ≤140℃, the ash content is < 15%, for example, the ash content is 1-13%, further 2-12%.

[0032] In the processing of the casting asphalt, the casting asphalt modifier in the embodiments of the present application can be dissolved and blended in 50# road asphalt at 170℃, which is 20℃ or more lower than the processing temperature when the natural asphalt is directly put into the 50# road asphalt; at the same time, there is no dust in the processing process, and the processing is environmentally friendly and safe. The processing method of the present application is simple and low in cost.

[0033] In order to further understand the present application, the present application is described in detail below in conjunction with examples, and the protection scope of the present application is not limited by the following examples. In the examples, each of the original reagents and materials can be commercially available, and the experimental method without specific experimental conditions is the conventional method and condition well known in the field. The.

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

[0035] Example 1

[0036] The Iranian natural asphalt and the softening oil are mixed in a high-speed mixer at a mass ratio of 80%:20% at 100rpm for 20 minutes. The mixture is then extruded in an extruder at a rotational speed of 100rpm, with no heating at the feeding end and a temperature of 240℃ at the compression and metering sections. The produced cast asphalt modifier is a solid particle (particle size of about 2-4mm) with a softening point of 110℃ and an ash content of 12%.

[0037] In the processing of cast asphalt, the cast asphalt modifier of the present application can be dissolved and mixed in 50# road asphalt at 170℃, which is 20℃ lower than the processing temperature when natural asphalt is directly added into 50# road asphalt. At the same time, there is no dust in the processing process, and the processing is environmentally friendly and safe.

[0038] In addition, the cast asphalt meets the technical requirements of Type III in “JT / T 1131.4-2023 Steel Bridge Pavement Part 4: Cast Asphalt”. The modifier addition amount is 15% of the low-grade asphalt, and the cast asphalt elongation is 14cm.

[0039] Example 2

[0040] The North American rock asphalt and the softening oil are mixed in a high-speed mixer at a mass ratio of 73%:27% at 100rpm for 20 minutes. The mixture is then extruded in an extruder at a rotational speed of 100rpm, with no heating at the feeding end and a temperature of 240℃ at the compression and metering sections. The produced cast asphalt modifier has a softening point of 120℃ and an ash content of 3%.

[0041] In the processing of the cast asphalt, the cast asphalt modifier of the present application can realize 170℃ dissolving and blending in the 50# road asphalt, which is 20℃ lower than the processing temperature of the natural asphalt directly put into the 50# road asphalt; meanwhile, there is no dust in the processing process, and the processing is environmentally friendly and safe. The modifier addition amount is 14% of the low-grade asphalt; and the cast asphalt ductility is 12cm.

[0042] Example 3

[0043] Xinjiang rock asphalt and softening oil are weighed according to the mass ratio of 75%:25%, and then mixed in a high-speed mixer at 100 revolutions / minute for 20 minutes. The mixed material is extruded in an extruder, the extruder speed is 100 revolutions / minute, the feeding end is not heated, and the compression segment and metering segment temperature is 240℃. The produced cast asphalt modifier softening point is 115℃, and the ash content is 4%.

[0044] In the processing of the cast asphalt, the cast asphalt modifier of the present application can realize 170℃ dissolving and blending in the 50# road asphalt, which is 20℃ lower than the processing temperature of the natural asphalt directly put into the 50# road asphalt; meanwhile, there is no dust in the processing process, and the processing is environmentally friendly and safe. The modifier addition amount is 14% of the low-grade asphalt; and the cast asphalt ductility is 12cm.

[0045] As can be seen from the above examples, the cast asphalt modifier obtained by the present application can reduce the processing temperature of the cast asphalt, and at the same time, improve the dissolving and dispersing speed of the natural asphalt. Furthermore, the present application forms a solid particle modifier through a new processing method, which reduces the dust pollution and the like in the processing process. Further, the softening point of the cast asphalt modifier described in the examples of the present application is between 110℃ and 140℃, which can ensure that the modifier will not produce sticky and caked phenomenon during long-distance transportation and long-time storage, thereby affecting feeding and melting and dispersing. It can also reduce the softening point of the natural asphalt, realize the rapid dissolving of rock asphalt at a lower temperature, and reduce the risk of asphalt aging caused by long-time high-temperature processing.

[0046] The examples of the present application are only examples for clearly illustrating the present application, and are not a limitation on the embodiments of the present application. For those skilled in the art, other different forms of changes or variations can be made on the basis of the above description, and here, it is not necessary or impossible to exhaust all the embodiments, and these obvious changes or variations extended from the spirit of the present application are still within the protection scope of the present application.

[0047] The above merely describes the preferred embodiments of the present application, and it should be pointed out that, for those skilled in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as falling within the protection scope of the present application.

Claims

1. A method for processing a pourable asphalt modifier, characterized in that: The following steps are involved: The high softening point natural asphalt and softening oil are mixed in proportion in a high-speed mixer, and then mixed and extruded at high temperature in 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 the 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 feeding 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 in the form of solid particles and has 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%.