Preparation method of modified emulsified asphalt for ultra-wearing layer

Abstract

The present invention relates to the technical field of asphalt emulsification. The present invention discloses a preparation method of a modified emulsified asphalt for a ultra-thin wearing course, including: Step S1, heating the base asphalt with a specified heating temperature in the range of 150°C - 175°C to 175°C; Step S2, heating the added water in the soap solution with a temperature specification of 50°C - 60°C to 50°C and adding an emulsifier; Step S3, the modified asphalt obtained in Step S1 is transported to a colloid mill through a main asphalt pipeline, and the soap solution obtained in Step S2 is transported to the colloid mill through a soap solution pipeline surrounding the outside of the main asphalt pipeline; Based on the standard of the ultra-thin wearing course emulsified asphalt, on the basis that the evaporation residue is greater than 65%, by this method, without referring to any external additional mechanism, the flow directions of the outlet of the colloid mill, the soap solution pipeline, and the main asphalt pipeline are changed, so that the viscosities of the modified asphalt and the soap solution entering the colloid mill meet the requirements. Thereby avoiding the problems of the final product being stringy and having large particles.

Description

Technical Field

[0001] The present invention relates to the technical field of asphalt emulsification, and specifically relates to a preparation method of modified emulsified asphalt for ultra-thin wearing course. Background Art

[0002] The most important function of spraying modified emulsified asphalt on the ultra-high adhesion wearing course is to improve the bonding ability between the emulsified asphalt mixture and the road surface. The particle size of emulsified asphalt is directly related to the stability of emulsified asphalt. The smaller the particle size and the narrower the distribution, the more stable the prepared emulsified asphalt. Therefore, high-speed shearing or colloid mill grinding is required during the preparation of emulsified asphalt. The processing process of emulsified asphalt is roughly divided into four steps: asphalt modification, soap solution preparation, mixing and emulsification, and cooling and storage. During the processing, the viscosity of asphalt changes by itself, resulting in large particle size of the final emulsified asphalt and the appearance of asphalt filaments. Summary of the Invention

[0003] The purpose of the present invention is to provide a preparation method of modified emulsified asphalt for ultra-thin wearing course to solve the problems raised in the above background art.

[0004] To achieve the above purpose, the present invention provides the following technical solutions:

[0005] A preparation method of modified emulsified asphalt for ultra-thin wearing course includes:

[0006] Step S1, preparation of modified asphalt: Heat the matrix asphalt with a specified heating temperature in the range of 150°C - 175°C to 175°C, add SBS modifier and other additives, perform high-speed shearing for 1 h, add a stabilizer, and fully stir and ripen to obtain SBS modified asphalt. The matrix asphalt is selected as SK70. After adding 3% - 4% SBS modifier to the matrix asphalt and then adding a stabilizer, the viscosity value measured by a Brookfield rotational viscometer of the modified asphalt prepared in S1 at 175°C is 0.3 Pa·s, and the viscosity value measured by a Brookfield rotational viscometer of the modified asphalt prepared in S1 at 160°C is 0.33 Pa·s. This viscosity fully meets the requirements of the conveying fluidity of asphalt and the final temperature requirement for emulsifying and grinding asphalt by a colloid mill.

[0007] Step S2, preparation of soap solution: Heat the water added to the soap solution with a temperature specification of 50°C - 60°C to 50°C, add an emulsifier, and adjust the pH value to the range of 2 - 4 by adding hydrochloric acid and other additives to obtain a soap solution. The temperature of the soap solution is in the range of 50°C - 60°C. Since the temperature difference between the soap solution and the external temperature is small and the temperature exchange rate is slow, in order to further reduce the temperature difference, the minimum value within the specified range is selected as the processing temperature of the soap solution for subsequent heating. The soap solution mainly contains water, emulsifier, stabilizer, and hydrochloric acid, and the mass ratio of water, emulsifier, stabilizer, and hydrochloric acid is 800:7:4:1;

[0008] Step S3, Preparation of Emulsified Asphalt: The modified asphalt obtained in step S1 is transported to a colloid mill through the main asphalt pipeline, and the soap solution obtained in step S2 is transported to the colloid mill through the soap solution pipeline surrounding the outside of the main asphalt pipeline. The feeding temperature of the modified asphalt in S1 in the colloid mill is greater than 160°C, the gap of the colloid mill is less than 1 mm, and the rotational speed of the colloid mill is above 2400 r / min to obtain emulsified asphalt. After the preparation of the modified asphalt in S1 and the soap solution in step S2, they can be premixed or mixed in the colloid mill. Since the evaporation residue in the preparation of the modified emulsified asphalt for the ultra-wearing course needs to be greater than 65%, the ratio of the modified asphalt in S1 to the soap solution in S2 increases. The mixed liquid is emulsified in the colloid mill with a gap of less than 1 mm and a rotational speed of above 2400 r / min to obtain emulsified asphalt;

[0009] Step S4, Cooling of the Finished Product: The temperature at the outlet of the colloid mill is 130°C. The pressure in the pipeline at the outlet of the colloid mill is stabilized at 0.15 - 0.25 MPa through a back-pressure device. The pipeline at the outlet of the colloid mill passes through the space between the main asphalt pipeline and the soap solution pipeline in S3 and exchanges heat with the main asphalt pipeline and the soap solution pipeline. The temperature exchange range between the pipeline at the outlet of the colloid mill and the main asphalt pipeline is 0 - 10°C. After the exchange, the pipeline at the outlet of the colloid mill is connected to a chiller and cooled to 30 - 40°C for storage as the final product. The temperature at the outlet of the colloid mill is 130°C, and the temperature of the finally discharged emulsified asphalt needs to be cooled again for storage. The heat of the finally discharged emulsified asphalt needs to be replaced twice, resulting in energy loss.

[0010] As a further solution of the present invention: In step S4, the pipeline at the outlet of the colloid mill exchanges temperature with the main asphalt pipeline, and at the same time, the pipeline at the outlet of the colloid mill exchanges temperature with the soap solution pipeline. In order to reduce the problem of large temperature difference, the main asphalt pipeline can only exchange temperature with the pipeline at the outlet of the colloid mill, and the soap solution pipeline can only exchange temperature with the pipeline at the outlet of the colloid mill. Since the temperature of the soap solution pipeline itself is not high, the soap solution pipeline located outside does not affect.

[0011] As a further solution of the present invention: In step S4, the heat transfer rate between the pipeline at the outlet of the colloid mill and the main asphalt pipeline is lower than the heat transfer rate between the pipeline at the outlet of the colloid mill and the soap solution pipeline.

[0012] As a further solution of the present invention: There is a pipeline with low thermal conductivity between the pipeline at the outlet of the colloid mill and the cooling pipeline.

[0013] As a further solution of the present invention: The movement direction of the soap solution pipeline is the same as that of the main asphalt pipeline, and the movement direction of the pipeline at the outlet of the colloid mill is opposite to that of the soap solution pipeline and the main asphalt pipeline.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: Based on the standard of the emulsified asphalt for the ultra-wearing course, on the basis that the evaporation residue is greater than 65%, by this method, without referring to any external additional mechanisms, the flow direction at the outlet of the colloid mill, the flow direction of the soap solution pipeline, and the flow direction of the main asphalt pipeline are changed. The modified asphalt is processed at the high value temperature in the standard range and the soap solution is processed at the low value temperature in the standard range. Using the emulsified asphalt discharge pipe as a medium, during the process of reaching the colloid mill, the soap solution is slowly adjusted from a low standard temperature to a high standard temperature, and the modified asphalt is slowly adjusted from a high standard temperature to a low standard temperature, so that the viscosities of the modified asphalt and the soap solution meet the requirements when entering the colloid mill. Thus, the problems of wire drawing and large particles in the final product are avoided. Brief Description of the Drawings

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0016] Figure 1 It is a diagram of a preparation method of a modified emulsified asphalt for an ultra-wearing course. Detailed Embodiments

[0017] Please refer to Figure 1 In this embodiment, in step S1, preparation of modified asphalt: The matrix asphalt with a specification heating temperature in the range of 150°C - 175°C is heated to 175°C, SBS modifier and other additives are added, and after high-speed shearing for 1 h, a stabilizer is added. After sufficient stirring and curing, SBS modified asphalt is obtained.

[0018] In this embodiment, the matrix asphalt is selected as SK70. After adding 3% - 4% SBS modifier to the matrix asphalt and then adding a stabilizer, the viscosity value of the modified asphalt prepared by S1 measured by a Brookfield rotational viscometer at 175°C is 0.3 Pa·s, and the viscosity value of the modified asphalt prepared by S1 measured by a Brookfield rotational viscometer at 160°C is 0.33 Pa·s. This viscosity fully meets the requirements for the transportation fluidity of the asphalt and the final temperature requirements for the emulsified asphalt processing and grinding of the colloid mill.

[0019] In this embodiment, in step S2, preparation of soap solution: The added water in the soap solution with a temperature specification of 50°C - 60°C is heated to 50°C, an emulsifier is added, and hydrochloric acid and other additives are added to adjust the pH value to the range of 2 - 4 to obtain the soap solution.

[0020] In this embodiment, the temperature of the soap solution is in the range of 50°C - 60°C. Since the temperature difference between the soap solution and the external temperature is small and the temperature exchange rate is slow, in order to further reduce the temperature difference, the processing temperature of the soap solution is selected as the minimum value within the specified range for subsequent heating. The soap solution mainly contains water, emulsifier, stabilizer, and hydrochloric acid, and the mass ratio of water, emulsifier, stabilizer, and hydrochloric acid is 800:7:4:1.

[0021] In this embodiment, for step S3, preparation of emulsified asphalt: The modified asphalt obtained in step S1 is transported to the colloid mill through the main asphalt pipeline, and the soap solution obtained in step S2 is transported to the colloid mill through the soap solution pipeline surrounding the outside of the main asphalt pipeline. The feeding temperature of the S1 modified asphalt in the colloid mill is greater than 160°C, the gap of the colloid mill is less than 1 mm, and the rotation speed of the colloid mill is above 2400 r / min to obtain emulsified asphalt.

[0022] In this embodiment, after the S1 modified asphalt and step S2, the soap solution are prepared, they can be premixed or mixed in the colloid mill. Since the evaporation residue in the preparation of the ultra-wearing course modified emulsified asphalt needs to be greater than 65%, the ratio of the S1 modified asphalt to the S2 soap solution is increased. The mixed liquid is emulsified in the colloid mill with a gap of less than 1 mm and a rotation speed of above 2400 r / min to obtain emulsified asphalt.

[0023] In this embodiment, for step S4, cooling of the finished product: The temperature at the outlet of the colloid mill is 130°C. The pressure in the pipeline at the outlet of the colloid mill is stabilized at 0.15 - 0.25 MPa through a backpressure device. The pipeline at the outlet of the colloid mill passes through the space between the main asphalt pipeline and the soap solution pipeline in S3 and exchanges heat with the main asphalt pipeline and the soap solution pipeline. The temperature exchange range between the pipeline at the outlet of the colloid mill and the main asphalt pipeline is 0 - 15°C. After the heat exchange, the pipeline at the outlet of the colloid mill is connected to a chiller and cooled to 30 - 40°C for storage as the final product.

[0024] In this embodiment, the temperature at the outlet of the colloid mill is 130°C, and the temperature of the finally discharged emulsified asphalt needs to be cooled down for a second time for storage. The heat of the finally discharged emulsified asphalt needs to be replaced for a second time, resulting in energy loss.

[0025] In this embodiment, the main asphalt pipeline transports S1 modified asphalt. The S1 modified asphalt has a temperature of 175 °C and a viscosity of 0.3 Pa·s. At the inlet of the main asphalt pipeline, the fluidity is the greatest. However, the temperature difference between the S1 modified asphalt and the room temperature is too large. Even though the main asphalt pipeline is insulated, due to the large temperature difference, temperature changes will still occur, resulting in too low a temperature inside the colloid mill and causing wire drawing problems. Therefore, the discharge pipeline of the colloid mill in S4 is used to surround the main asphalt pipeline, reducing the temperature difference between the two to 45 °C. Compared with the room temperature difference, the temperature difference value is reduced by 100 °C. At the same time, affected by heat transfer, the temperature of the pipeline at the outlet of the colloid mill will rise, but the temperature difference is small, and the heating and cooling effects on the pipeline at the outlet of the colloid mill and the main asphalt pipeline are not significant.

[0026] In this embodiment, the pipeline at the outlet of the colloid mill is exposed to the outside at this time, and the temperature difference between the pipeline at the outlet of the colloid mill and the room temperature is also 100 °C. Therefore, to further prevent the temperature of the pipeline at the outlet of the colloid mill from dropping too fast, the S2 soap solution pipeline is surrounded outside the pipeline at the outlet of the colloid mill. At this time, the S2 soap solution pipeline has a heat exchange reaction with the outside, and the S2 soap solution pipeline has a heat exchange reaction with the pipeline at the outlet of the colloid mill. At this time, due to the further reduction of the temperature difference between the S2 soap solution pipeline and the pipeline at the outlet of the colloid mill, the temperature of the S2 soap solution pipeline is in a slow rising state while the temperature inside the pipeline at the outlet of the colloid mill is in a slow falling state. And the pipeline at the outlet of the colloid mill is also affected by the temperature rise of the modified asphalt pipeline, making the final temperature of the pipeline at the outlet of the colloid mill uncertain. And the pipeline at the outlet of the colloid mill finally needs secondary cooling. Therefore, the temperature of the emulsified asphalt in the part of the pipeline at the outlet of the colloid mill that exchanges with the soap solution pipeline and the main asphalt pipeline does not affect the quality of the final product. It can be determined that the soap solution pipeline is in a heating state, the temperature of the main asphalt pipeline is in a cooling state, and the soap solution and the modified asphalt are also affected by the pipeline at the outlet of the colloid mill, greatly reducing the temperature difference. Thus, within the specified range, the maximum temperature value within the specified range is used as the processing temperature of the modified asphalt, and the minimum temperature value of the soap solution within the specified range is used. This will not only not affect the quality and quality of the modified asphalt and the soap solution. And by utilizing the temperature intermediary characteristics of the pipeline at the outlet of the colloid mill under the condition of overcoming external influences, the soap solution is slowly adjusted from a low standard temperature to a high standard temperature, and the modified asphalt is slowly adjusted from a high standard temperature to a low standard temperature, so that the viscosities of the modified asphalt and the soap solution entering the colloid mill meet the requirements. Thus, problems such as wire drawing and large particles in the final product are avoided.

[0027] In this embodiment, in step S4, the pipeline at the outlet of the colloid mill exchanges temperature with the main asphalt pipeline, and at the same time, the pipeline at the outlet of the colloid mill exchanges temperature with the soap solution pipeline.

[0028] In this embodiment, in order to reduce the problem of large temperature difference, the main asphalt pipeline can only exchange temperature with the pipeline at the outlet of the colloid mill, and the soap solution pipeline can only be replaced with the pipeline at the outlet of the colloid mill. Since the temperature of the soap solution pipeline itself is not high, the location of the soap solution pipeline outside does not affect.

[0029] In this embodiment, in step S4, the heat transfer rate between the pipeline at the outlet of the colloid mill and the main asphalt pipeline is lower than the heat transfer rate between the pipeline at the outlet of the colloid mill and the soap solution pipeline.

[0030] In this embodiment, a paving layer and an intermediate layer can be added between the pipeline at the outlet of the colloid mill and the main asphalt pipeline to reduce temperature transfer. Since the flow rate of the modified asphalt will change due to viscosity, if the speed is reduced too quickly, it is easy to cause the temperature of the modified asphalt to drop too much, so that when it is mixed with the soap solution, secondary temperature adjustment is carried out, resulting in the final temperature being lower than the optimal processing temperature of the colloid mill.

[0031] In this embodiment, there is a low thermal conductivity pipeline between the pipeline at the outlet of the colloid mill and the cooling pipeline. Since the modified emulsified asphalt finally discharged from the colloid mill needs to be cooled and stored, the pipeline is prevented from transferring temperature. There is a low thermal conductivity pipeline between the pipeline at the outlet of the colloid mill and the cooling pipeline. Thus, the above temperature replacement process will not be affected.

[0032] In this embodiment, the movement directions of the soap solution pipeline and the main asphalt pipeline are the same, and the movement directions of the pipeline at the outlet of the colloid mill and the soap solution pipeline and the main asphalt pipeline are opposite.

[0033] This setting method will not increase the pipeline lengths of the soap solution pipeline and the main asphalt pipeline, but only increase the pipeline length of the pipeline at the outlet of the colloid mill. Since the emulsified asphalt in the pipeline at the outlet of the colloid mill needs to be cooled, the increase in the length of the pipeline at the outlet of the colloid mill is also beneficial to cooling.

[0034] The above is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent replacements or changes, and should be covered by the protection scope of the present invention.

Claims

1. A method for preparing super wear layer modified emulsified asphalt, characterized in that: include: Step S1, preparation of modified asphalt: heating the base asphalt with a specification heating temperature in the range of 150°C-175°C to 175°C, adding SBS modifier and other additives, subjecting to high-speed shearing for 1 hour, adding stabilizer, and fully stirring and aging to obtain SBS modified asphalt; Step S2, preparing soap solution: heating the added water in the soap solution with a temperature specification of 50°C-60°C to 50°C, adding an emulsifier, and adding hydrochloric acid and other additives to adjust the pH value to a range of 2-4 to obtain soap solution; Step S3, preparation of emulsified asphalt: the modified asphalt obtained in step S1 is transported to the colloid mill through the main asphalt pipeline, and the soap solution obtained in step S2 is transported to the colloid mill through the soap solution pipeline surrounding the outside of the main asphalt pipeline, the feed temperature of the S1 modified asphalt in the colloid mill is greater than 160°C, the gap of the colloid mill is less than 1mm, and the rotation speed of the colloid mill is above 2400r / min, to obtain emulsified asphalt; Step S4, finished product cooling: the outlet temperature of the colloid mill is 130°C, the outlet pipeline of the colloid mill is stabilized at a pressure of 0.15-0.25MPa through a back pressure device, the outlet pipeline of the colloid mill passes through the main asphalt pipeline and the soap liquid pipeline in S3, and exchanges heat with the main asphalt pipeline and the soap liquid pipeline. The heat exchange temperature range of the colloid mill outlet pipeline and the main asphalt pipeline is 0-15°C. The colloid mill outlet pipeline after the exchange is connected to the chiller and is reduced to 30-40°C by the chiller for storage as the final product; the soap liquid pipeline moves in the same direction as the main asphalt pipeline, and the colloid mill outlet pipeline moves in the opposite direction to the soap liquid pipeline and the main asphalt pipeline.

2. The method for preparing a super wearing layer modified emulsified asphalt according to claim 1, characterized in that: In step S4, the colloid mill outlet pipeline and the main asphalt pipeline exchange temperatures, and the colloid mill outlet pipeline and the soap solution pipeline exchange temperatures at the same time.

3. The method for preparing a super wearing layer modified emulsified asphalt according to claim 1, characterized in that: In step S4, the heat transfer rate between the colloid mill outlet pipeline and the main asphalt pipeline is lower than the heat transfer rate between the colloid mill outlet pipeline and the soap solution pipeline.

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