Process and equipment for in-situ regeneration of aged asphalt by using double-frequency ultrasound

Abstract

The invention belongs to the technical field of building materials, and particularly relates to a process and equipment for in-situ regeneration of aged asphalt by using double-frequency ultrasound. According to the process, aged asphalt in a molten state is placed in a tank body, double-frequency ultrasonic treatment is applied under the heating and stirring conditions, the cavitation effect of double-frequency ultrasound is utilized to synergistically promote conversion of heavy components into light components in the asphalt, and in-situ regeneration of the aged asphalt is achieved. The equipment can meet the treatment requirement of aged asphalt, and comprises a base, a tank body, a heating device, a temperature controller, a temperature sensor, a motor, a stirring paddle, a double-frequency ultrasonic generator, an adjustable bracket and the like. Compared with a traditional process, the process has the advantages that an exogenous regenerant does not need to be added, in-situ regeneration directly causes physical and chemical changes in the asphalt, and through the synergistic effect of low frequency and high frequency, the cavitation intensity is enhanced, the action range is widened, and the regeneration efficiency is improved. After treatment, the physical property of the aged asphalt is remarkably improved, and the aged asphalt is suitable for road maintenance and waste asphalt resource utilization.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology, specifically relating to a process and equipment for in-situ regeneration of aged asphalt using dual-frequency ultrasound. Background Technology

[0002] Asphalt is an indispensable material in road construction. During its use, affected by natural and human factors, asphalt pavements gradually age, leading to a decline in performance. Eventually, old pavements that can no longer continue to serve need to be removed and recycled, generating a large amount of waste asphalt material. Simply landfilling this waste asphalt material would result in significant resource waste, land occupation, and environmental pollution. Therefore, how to regenerate waste asphalt material and restore its performance to the level of base asphalt, thus promoting resource recycling, has become an urgent problem to be solved in the road transportation sector.

[0003] The aging process of asphalt includes the loss of light components through volatilization, association of polar molecules, condensation and aggregation of macromolecules, an increase in the C / H ratio, and an increase in unsaturation. Traditionally, asphalt aging is considered an irreversible process. Therefore, current research, both domestically and internationally, typically improves the performance of aged asphalt by adding rejuvenating agents. The main principle is to directly replenish the lost light components in the aged asphalt, reversing its properties and restoring it to its initial state where it can be reused. While existing research has yielded many results and advances, it is limited by exogenous rejuvenating agents. Therefore, developing a method for recycling waste asphalt materials without relying on rejuvenating agents is of great significance.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a process and equipment for in-situ regeneration of aged asphalt using dual-frequency ultrasound. This invention applies ultrasound waves to molten liquid asphalt, inducing ultrasonic cavitation effects within the asphalt. These effects include a series of dynamic behaviors such as cavitation bubble growth, compression, and collapse, as well as secondary effects such as microjets, shock waves, and free radical generation. Utilizing the thermal and mechanical effects of ultrasound, combined with secondary effects such as microjets and shock waves, physical and chemical reactions such as chain breaking, ring opening, and depolymerization can be promoted in aged asphalt, causing the transformation of heavy components into light components and promoting the performance recovery and regeneration of aged asphalt. This invention introduces dual-frequency ultrasound technology. Compared to single-frequency cavitation, the synergistic effect of low frequencies (e.g., 20kHz) and high frequencies (e.g., 40kHz) significantly enhances the intensity and uniformity of the cavitation effect, achieving in-situ regeneration of aged asphalt. Compared to traditional recycling methods that add rejuvenating agents, ultrasonic cavitation technology directly promotes the transformation of asphalt components through a synergistic physical-chemical process, reducing dependence on exogenous rejuvenating agents and providing a green and efficient new approach for the recycling of aged asphalt.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: On one hand, the present invention provides a device for in-situ regeneration of aged asphalt using dual-frequency ultrasonic technology, comprising a base, a tank, a motor, and a stirring paddle. The tank is fixed to the base by a tank support; the bottom of the tank has a discharge port; the inner wall of the tank is equipped with a heating device; the heating device is equipped with a temperature sensor; the base is equipped with a temperature controller; the temperature sensor is connected to the input terminal of the temperature controller to sense the temperature inside the tank and transmit it to the temperature controller via a signal line; the output terminal of the temperature controller is connected to the heating device to control the operation and stop of the heating device; the base is equipped with a motor mounting bracket; the motor is fixed to the motor mounting bracket by a clamping component. The lower end of the stirring paddle is connected to the motor shaft via a stirring paddle base; the stirring paddle extends into the bottom of the tank; the base is equipped with adjustable bracket A and adjustable bracket B, which respectively hold a low-frequency transducer and a high-frequency transducer; the base is equipped with a low-frequency ultrasonic generator and a high-frequency ultrasonic generator; the low-frequency ultrasonic generator and the high-frequency ultrasonic generator are respectively connected to the low-frequency transducer and the high-frequency transducer; the amplitude transformer and vibrating head of the low-frequency transducer and the high-frequency transducer extend into the interior of the tank and do not contact the stirring paddle; the temperature controller, temperature sensor, motor, low-frequency ultrasonic generator, and high-frequency ultrasonic generator are wired to an external power supply.

[0007] In some embodiments of the present invention, the heating device consists of an insulating layer and an electric heating wire.

[0008] In some embodiments of the present invention, the tank body is made of thermal insulation material to improve energy efficiency.

[0009] In some embodiments of the present invention, the low-frequency transducer and the high-frequency transducer move up and down, move horizontally, or rotate around an axis along the adjustable bracket A and the adjustable bracket B, respectively, so as to adjust the position and direction of the ultrasonic waves and achieve uniform processing over the entire area.

[0010] On the other hand, the present invention provides a process for in-situ regeneration of aged asphalt using dual-frequency ultrasound. The process employs the aforementioned equipment for in-situ regeneration of aged asphalt using dual-frequency ultrasound, and the specific steps are as follows: Step 1: Weigh the aged asphalt and heat it to a molten state before placing it into the tank; Step 2: Adjust adjustable bracket A and adjustable bracket B to move the vibrating heads of the low-frequency transducer and the high-frequency transducer to the middle and lower parts of the tank to avoid interference with the stirring paddle; after powering on, set the heating temperature through the thermostat; set the motor speed; set the low-frequency frequency and ultrasonic power of the low-frequency ultrasonic generator; set the high-frequency frequency and ultrasonic power of the high-frequency ultrasonic generator. Step 3: Start the heating device via the thermostat. After the temperature sensor shows that the set temperature has been reached, start the motor, low-frequency ultrasonic generator and high-frequency ultrasonic generator in sequence. The dual-frequency generator works together to continuously process the system. During this period, the thermostat keeps the system temperature stable. Step 4: After the predetermined processing time is reached, turn off the high-frequency ultrasonic generator, low-frequency ultrasonic generator, motor and heating device in sequence, open the discharge port and collect the recycled asphalt.

[0011] In some embodiments of the present invention, the heating temperature in step 2 is 160°C.

[0012] In some embodiments of the present invention, the low-frequency ultrasonic generator in step 2 has a low-frequency frequency of 20kHz and an ultrasonic power of 400W.

[0013] In some embodiments of the present invention, the high frequency of the high-frequency ultrasonic generator in step 2 is 40kHz and the ultrasonic power is 600w.

[0014] In some embodiments of the present invention, the motor speed in step 2 is 3000 rpm.

[0015] In some embodiments of the present invention, the processing time in step 3 is 5 minutes.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention introduces ultrasound into the regeneration process of aged asphalt without adding a rejuvenating agent. Through the mechanical action and secondary effects of ultrasound, physical and chemical reactions such as chain breaking, ring opening, and depolymerization in the aged asphalt are promoted, enabling the transformation of heavy components into light components in the aged asphalt without the addition of a rejuvenating agent, thus promoting the recovery of the aged asphalt's properties.

[0017] 2. This invention can effectively expand the range and intensity of cavitation effect and improve the conversion efficiency of aged asphalt components through the combined effect of low-frequency and high-frequency ultrasound.

[0018] 3. This invention utilizes a dual-frequency ultrasonic in-situ regeneration device for aged asphalt, featuring a simple structure and convenient operation. A temperature controller allows for precise temperature control of the heating device, maintaining the temperature of the aged asphalt within a preset range during the ultrasonic regeneration process to ensure quality. The stirring paddle enhances the mixing efficiency of the aged asphalt near the ultrasonic tool head, improving the coverage and quality of the regenerated asphalt. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the device for in-situ regeneration of aged asphalt using dual-frequency ultrasound, as per the present invention.

[0020] Among them, 1-base, 2-tank body, 3-tank body support, 4-discharge port, 5-heating device, 6-temperature controller, 7-temperature sensor, 8-motor fixing bracket, 9-clamping component, 10-motor, 11-stirring paddle, 12-low frequency ultrasonic generator, 13-high frequency ultrasonic generator, 14-adjustable bracket A, 15-adjustable bracket B, 16-low frequency transducer, 17-high frequency transducer. Detailed Implementation

[0021] To facilitate understanding of the present invention, a more comprehensive description will be given below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0022] In this embodiment of the invention, the asphalt material in the aged asphalt mixture is recovered using an asphalt mixture extractor. Example 1

[0023] A device for in-situ regeneration of aged asphalt using dual-frequency ultrasonic technology includes a base 1, a tank 2, a motor 10, and a stirring paddle 11. The tank 2 is fixed to the base 1 by a tank support 3. A discharge port 4 is provided at the bottom of the tank 2. A heating device 5 is provided on the inner wall of the tank 2. A temperature sensor 7 is provided on the heating device 5. A temperature controller 6 is provided on the base 1. The temperature sensor 7 is connected to the input terminal of the temperature controller 6 to sense the temperature inside the tank 2 and transmit it to the temperature controller 6 via a signal line. The output terminal of the temperature controller 6 is connected to the heating device 5 to control its operation and shutdown. A motor mounting bracket 8 is provided on the base 1. The motor 10 is fixed to the motor mounting bracket 8 by a clamping component 9. The lower end of the stirring paddle 11 is connected to the shaft of the motor 10 via a stirring paddle base. The stirring paddle 11 extends into the bottom of the tank 2. An adjustable bracket A 14 and an adjustable bracket B 15 are provided on the base 1. The adjustable bracket A 14... 14. Adjustable bracket B 15 clamps low-frequency transducer 16 and high-frequency transducer 17 respectively; low-frequency ultrasonic generator 12 and high-frequency ultrasonic generator 13 are provided on the base 1; low-frequency ultrasonic generator 12 and high-frequency ultrasonic generator 13 are connected to low-frequency transducer 16 and high-frequency transducer 17 respectively; the amplitude transformer and vibrating head of low-frequency transducer 16 and high-frequency transducer 17 extend into the interior of tank 2 and do not contact the stirring paddle 11; the temperature controller 6, temperature sensor 7, motor 10, low-frequency ultrasonic generator 12, and high-frequency ultrasonic generator 13 are wired to an external power supply.

[0024] Specifically, the heating device 5 consists of an insulating layer and an electric heating wire.

[0025] Specifically, the tank body 2 is made of thermal insulation material to improve energy efficiency.

[0026] Specifically, the low-frequency transducer 16 and the high-frequency transducer 17 move up and down, move horizontally, or rotate around the axis along the adjustable bracket A 14 and the adjustable bracket B 15, respectively, so as to adjust the position and direction of the ultrasonic waves and achieve uniform processing over the entire area.

[0027] A process for in-situ regeneration of aged asphalt using dual-frequency ultrasound, wherein the process employs the aforementioned equipment for in-situ regeneration of aged asphalt using dual-frequency ultrasound, and the specific steps are as follows: Step 1: Weigh 250g of aged asphalt sample and place it in an oven. Heat it until it reaches a molten state, and then place it in tank 2. Step 2: Adjust adjustable brackets A-14 and B-15 to move the vibrating heads of the low-frequency transducer 16 and high-frequency transducer 17 to the middle and lower parts of the tank 2, avoiding interference with the stirring paddle 11. After powering on, set the heating temperature to 160℃ using the temperature controller 6. Set the low-frequency ultrasonic generator 12 to 20kHz and the high-frequency ultrasonic generator 13 to 40kHz, and set the ultrasonic power to 400W and 600W respectively. Set the motor 10 speed to 3000rpm to ensure uniform stirring.

[0028] Step 3: Start the heating device 5 via the temperature controller 6. After the temperature sensor 7 displays that the set temperature has been reached, start the motor 10, low-frequency ultrasonic generator 12, and high-frequency ultrasonic generator 13 in sequence. Low-frequency ultrasound mainly promotes the formation and collapse of large cavitation bubbles, generating a strong mechanical effect; high-frequency ultrasound generates a large number of small cavitation bubbles, enhancing the chemical effect. The dual-frequency synergistic effect continues to process for the predetermined time of 5 minutes, during which the temperature controller 6 maintains a stable temperature within the system.

[0029] Step 4: After the predetermined processing time is reached, turn off the high-frequency ultrasonic generator 13, the low-frequency ultrasonic generator 12, the motor 10 and the heating device 5 in sequence, open the discharge port 4, wear protective equipment to collect the recycled asphalt sample and conduct subsequent performance tests. Example 2

[0030] The equipment for in-situ regeneration of aged asphalt using dual-frequency ultrasound in this embodiment is the same as that in Embodiment 1. The process for in-situ regeneration of aged asphalt using dual-frequency ultrasound differs from that in Embodiment 1 in that the predetermined time in step 3 is 10 minutes, while the rest is the same as in Embodiment 1. Example 3

[0031] The equipment for in-situ regeneration of aged asphalt using dual-frequency ultrasound in this embodiment is the same as that in Embodiment 1. The process for in-situ regeneration of aged asphalt using dual-frequency ultrasound differs from that in Embodiment 1 in that the predetermined time in step 3 is 15 minutes, while the rest is the same as in Embodiment 1. Example 4

[0032] The equipment for in-situ regeneration of aged asphalt using dual-frequency ultrasound in this embodiment is the same as that in Embodiment 1. The process for in-situ regeneration of aged asphalt using dual-frequency ultrasound differs from that in Embodiment 1 in that the motor 10 is set to a speed of 4500 rpm in step 2, while the rest is the same as in Embodiment 1. Example 5

[0033] The equipment for in-situ regeneration of aged asphalt using dual-frequency ultrasound in this embodiment is the same as that in Embodiment 1. The process for in-situ regeneration of aged asphalt using dual-frequency ultrasound differs from that in Embodiment 1 in that the motor 10 is set to a speed of 6000 rpm in step 2, while the rest is the same as in Embodiment 1.

[0034] This invention analyzes the three major indicators of aged asphalt and recycled aged asphalt obtained by extraction: penetration at 25℃, softening point, and ductility at 15℃. The performance test results are shown in Table 1.

[0035] Table 1. Basic parameters of aged asphalt after recycling treatment

[0036] The data above shows that the macroscopic properties of aged asphalt are hardening and brittleness, specifically a decrease in penetration and ductility, and an increase in softening point. After treatment with the equipment and process of this invention, the aged asphalt exhibits certain performance improvements, with increased penetration and ductility, and a decreased softening point. This indicates that dual-frequency ultrasonic treatment can successfully regenerate the conventional physical properties of aged asphalt, reduce its viscosity, and improve its fluidity. The above description is only for better explaining the embodiments of the present invention and is not intended to limit them. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention shall fall within the scope of the present invention.

Claims

1. An apparatus for rejuvenating aged asphalt in situ using dual frequency ultrasound, characterized by, The utility model relates to a device for in-situ regeneration of aged asphalt by double-frequency ultrasonic waves, which comprises a base, a tank, a motor and a stirring paddle, the tank is fixed on the base by a tank support, the bottom of the tank is provided with a discharge port, the inner wall of the tank is provided with a heating device, the heating device is provided with a temperature sensor, the base is provided with a temperature controller, the temperature sensor is connected with the input end of the temperature controller, is used for sensing the temperature in the tank and transmitting the temperature to the temperature controller through a signal line, the output end of the temperature controller is connected with the heating device, is used for controlling the operation and stop of the heating device, the base is provided with a motor fixing support, the motor is fixed on the motor fixing support by a clamping part, the lower end of the stirring paddle is connected with the rotating shaft of the motor through a stirring paddle bottom support, the stirring paddle extends into the bottom of the tank, the base is provided with adjustable support A and adjustable support B, the adjustable support A and the adjustable support B clamp a low-frequency transducer and a high-frequency transducer respectively, the base is provided with a low-frequency ultrasonic generator and a high-frequency ultrasonic generator, the low-frequency ultrasonic generator and the high-frequency ultrasonic generator are connected with the low-frequency transducer and the high-frequency transducer respectively, the amplitude lever and the vibration head of the low-frequency transducer and the high-frequency transducer extend into the inside of the tank and do not contact the stirring paddle, the temperature controller, the temperature sensor, the motor, the low-frequency ultrasonic generator and the high-frequency ultrasonic generator are connected with an external power supply by wires.

2. The apparatus for regenerating aged asphalt in situ using dual-frequency ultrasound according to claim 1, characterized in that, The heating device is composed of an isolation layer and an electric heating wire.

3. The apparatus for regenerating aged asphalt in situ using dual-frequency ultrasound according to claim 2, characterized in that, The tank is made of a heat-insulating material to improve energy efficiency.

4. The apparatus for rejuvenating aged asphalt in situ using dual frequency ultrasound according to claim 1, wherein, The low-frequency transducer and the high-frequency transducer move up and down, horizontally or rotate around the shaft along the adjustable support A and the adjustable support B to adjust the position and direction of the ultrasonic waves and realize uniform treatment in the whole area.

5. A process for rejuvenating aged asphalt in situ with dual frequency ultrasound, characterized in that, The device for in-situ regeneration of aged asphalt by double-frequency ultrasonic waves is used according to any one of claims 1-4, and the specific steps are as follows: Step 1: weigh the aged asphalt, heat it to a molten state, and then place it in the tank; Step 2: adjust the adjustable support A and the adjustable support B, move the vibration heads of the low-frequency transducer and the high-frequency transducer to the lower part in the tank to avoid interference with the stirring paddle, set the heating temperature by the temperature controller after power-on, set the low-frequency frequency and ultrasonic power of the low-frequency ultrasonic generator, set the high-frequency frequency and ultrasonic power of the high-frequency ultrasonic generator, and set the motor speed; Step 3: start the heating device by the temperature controller, start the motor, the low-frequency ultrasonic generator and the high-frequency ultrasonic generator in sequence when the temperature sensor shows that the temperature reaches the set temperature, and keep the temperature in the system stable by the temperature controller during the continuous treatment by the double-frequency cooperation; Step 4: turn off the high-frequency ultrasonic generator, the low-frequency ultrasonic generator, the motor and the heating device in sequence when the predetermined treatment time is reached, open the discharge port, and collect the regenerated asphalt.

6. The process for rejuvenating aged asphalt in situ with dual frequency ultrasound of claim 5, wherein, The heating temperature in step 2 is 160℃.

7. The process for rejuvenating aged asphalt in situ with dual frequency ultrasound of claim 5, wherein, The low-frequency frequency of the low-frequency ultrasonic generator in step 2 is 20 kHz, and the ultrasonic power is 400 w.

8. The process for rejuvenating aged asphalt in situ with dual frequency ultrasound of claim 5, wherein, The high-frequency frequency of the high-frequency ultrasonic generator in step 2 is 40 kHz, and the ultrasonic power is 600 w.

9. The process for rejuvenating aged bitumen in situ using dual frequency ultrasound as claimed in claim 5 wherein, The motor speed in step 2 is 3000 rpm.

10. The process for rejuvenating aged asphalt in situ with dual frequency ultrasound of claim 5, wherein, The time for the continuous treatment in step 3 is 5 min. The time for the continuous treatment in step 3 is 5 min. The time

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