A system and method for evaluating asphalt-aggregate adhesion

Abstract

The present application relates to a system and method for evaluating asphalt-aggregate adhesion. The system for evaluating asphalt-aggregate adhesion of the present application can be used to quantitatively evaluate asphalt-aggregate adhesion, avoiding the influence of subjective factors. The evaluation method of the present application uses the system of the present application, calculates the adhesion loss kinetic energy between asphalt and aggregate using the test data measured by the system, and further evaluates the adhesion. The method has a simple and practical test process, and can quickly obtain stable and reliable test results.

Description

Technical Field

[0001] This invention belongs to the field of asphalt adhesion technology, specifically relating to a system and method for evaluating asphalt-aggregate adhesion. Background Technology

[0002] In modern highway construction, asphalt mixtures, as a composite material with excellent road performance, are widely used, accounting for over 95% of highways and Class I roads, and typically over 80% of Class II roads. Their superior mechanical properties, durability, and driving comfort make them the preferred material for high-grade pavements. In asphalt mixtures, asphalt acts as a binder, filling the pores and depressions on the surface of mineral aggregates. Through physical adsorption and chemical bonding, it firmly binds the aggregate particles, forming an integral pavement structure layer. The adhesion performance of the asphalt-aggregate interface is a key factor determining the mechanical properties and service life of asphalt mixtures. It directly affects not only the mixture's high-temperature rutting resistance, low-temperature crack resistance, and fatigue durability, but also its resistance to water damage. Especially in humid and rainy areas, the quality of asphalt-aggregate interface adhesion directly affects the pavement's service life and maintenance costs. Therefore, in-depth research into the asphalt-aggregate interface adhesion mechanism and the establishment of a scientific and reasonable adhesion evaluation method are of significant theoretical and engineering application value for improving asphalt pavement quality and extending its service life.

[0003] Regarding the adhesion between asphalt and aggregates, the commonly used methods in the specifications are the boiling water method and the immersion water method. These methods are simple to operate and quick, but they mainly rely on subjective judgment, resulting in large errors and making quantitative analysis impossible. Specific quantitative methods include pull-out tests, atomic force microscopy, and molecular dynamics simulations. Although the results are precise, the operations are too complex, time-consuming, and not intuitive enough. Meanwhile, many scholars have proposed evaluation methods. Patent CN109187271A proposes a cold-mix asphalt adhesion test and quantitative evaluation method, which evaluates asphalt aggregate adhesion by calculating the adhesion rate after immersing cold-mix material particles in boiling water. Patent CN110864995A proposes an automated testing device and evaluation method for testing the adhesion between asphalt and coarse aggregate, judging the quality of adhesion by calculating the mass loss rate P. Patent CN111398166A proposes a quantitative aggregate-asphalt adhesion testing device and experimental method, similar to a pull-out test, evaluating asphalt-aggregate adhesion by the maximum tensile force at the point of separation of the adhesive tape. Patent CN118624518A proposes an evaluation method for aggregate-asphalt adhesion, evaluating the adhesion coefficient R by calculating the displacement-tensile area. These methods are broadly classified into boiling water and pull-out tests. While they can quantitatively analyze the adhesion between asphalt and aggregate, the operation process is too cumbersome and lacks convenience. Therefore, there is an urgent need to develop a device for measuring asphalt-aggregate adhesion, which is characterized by accurate quantification, simple operation, and short processing time. Summary of the Invention

[0004] To address the problems existing in the prior art, the purpose of this invention is to provide a system for evaluating asphalt-aggregate adhesion, including a test chamber and an inclined plane system for aggregate balls to roll off. The inclined plane system includes an inclined panel and a bottom support plate hinged to the inclined panel; the inclined panel is provided with a plurality of rolling tracks for setting the asphalt film; the walls of the rolling tracks are provided with a mechanism for measuring the speed of the aggregate balls as they roll to the end of the rolling track. Speed ​​measuring device.

[0005] Based on the above scheme, the inclined plane system also includes a height adjustment device for adjusting the angle between the inclined panel and the bottom support plate to obtain different rolling track slopes.

[0006] Based on the above scheme, a ball launching cylinder is provided at the front end of the rolling track to make the initial velocity of the aggregate balls zero when they roll down and to make the landing position the same each time. The ball launching cylinder is provided with a telescopic stop to stop the movement of the aggregate balls.

[0007] Based on the above scheme, the test main body box is equipped with a heating device for providing a heat source to control the inside of the test main body box, and a blower motor and an exhaust port are also installed on the top wall of the test main body box.

[0008] The present invention also provides a method for evaluating asphalt-aggregate adhesion, the method comprising the following steps: S1 heats the asphalt to a fluid state and slowly injects it back and forth into one of the rolling tracks of the inclined plane system. After cooling at room temperature for 30 minutes, the asphalt film is smoothed with a hot scraper. No asphalt film is placed in the other rolling track of the same inclined plane system. S2 places small aggregate balls of the same diameter and material into the launching tubes of two rolling tracks, and adjusts the height adjustment device to make the slope angle of the rolling track reach the preset angle. S3 Place the inclined plane system into the test chamber and control the temperature inside the test chamber at 100℃ for 1 hour; S4 simultaneously retracts the telescopic stops on both ball-launching cylinders, causing the aggregate balls to roll downwards from a stationary state; S5 When the aggregate balls roll to the end of the rolling track, the speed of the two aggregate balls is measured by the speed measuring device. and ; S6 calculates the lost kinetic energy. ; in, The energy lost is kinetic energy; m is the mass of the aggregate pellets; The speed at which the aggregate balls roll down a smooth rolling track to the bottom; The speed at which the aggregate balls roll down the asphalt-coated track to the bottom.

[0009] S7 determines the adhesion level based on the magnitude of the lost kinetic energy.

[0010] Based on the above scheme, step S7, which determines the adhesion level according to the magnitude of the lost kinetic energy, is as follows: When the loss kinetic energy is 1300~2000J·10 -5 At this time, the adhesion grade is 5, which means that the asphalt has extremely strong adhesion to the aggregate, is not easy to peel off, and is suitable for heavy loads and harsh environments. When the loss kinetic energy is 700~1300J·10 -5 At this time, the adhesion grade is 4, which means that the asphalt has strong adhesion to the aggregate, good durability and anti-stripping performance, and meets the needs of most road engineering projects. When the loss of kinetic energy is 400~700J·10 -5When the adhesion grade is 3, it means that the adhesion of asphalt to aggregate is average, the bond between aggregate and asphalt is not stable enough, and adhesion is prone to decline in humid environments. When the loss of kinetic energy is 200~400 J·10 -5 At this time, the adhesion grade is 2, which means that the adhesion of asphalt to aggregate is weak and asphalt peeling is likely to occur. When the lost kinetic energy is 0~200J·10 -5 At this point, the adhesion grade is 1, which means that the asphalt has almost no effective adhesion to the aggregate, making it extremely susceptible to water damage and structural failure, and therefore unsuitable for engineering projects.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: The system for evaluating asphalt-aggregate adhesion of the present invention can be used to quantitatively evaluate asphalt-aggregate adhesion, avoiding the influence of subjective factors. The evaluation method of the present invention uses the system to calculate the adhesion loss kinetic energy between asphalt and aggregate based on the test data measured by the system, thereby evaluating their adhesion. This method has a simple and practical test procedure, can quickly obtain test results, and is stable and reliable. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the system structure of the present invention; Figure 2 This is a schematic diagram of the inclined plane system in the system of the present invention; Figure 3 This is a top-view structural diagram of the inclined plane system in the system of this invention; Figure 4 This is a schematic diagram of the ball-launching tube in the inclined plane system of the present invention; Figure 5 This is a comparison chart of the adhesion level test results between Example 3 and Comparative Example 1; Figure 6 The graph shows the basalt adhesion test results for Example 3 and Comparative Example 2; Figure 7 The graph shows the limestone adhesion test results for Example 3 and Comparative Example 2. Figure 8 The graph shows the granite adhesion test results for Example 3 and Comparative Example 2. Detailed Implementation

[0013] The terminology used in this invention, unless otherwise specified, generally has the meanings commonly understood by those skilled in the art. The invention is further described in detail below with reference to specific embodiments and data. The following embodiments are merely illustrative and are not intended to limit the scope of the invention in any way.

[0014] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the experimental materials, reagents, and chemicals used in the following embodiments can be obtained through general channels. Example 1

[0015] A system for evaluating asphalt-aggregate adhesion, the system comprising a test chamber 1 and an inclined plane system 2 for aggregate balls to roll off; The inclined plane system 2 includes an inclined panel 2-1 and a bottom support plate 2-2 hinged to the inclined panel 2-1; the inclined panel 2-1 is provided with a plurality of rolling tracks 2-11 for setting the asphalt film; the walls of the rolling tracks 2-11 are provided with a mechanism for obtaining the speed of the aggregate balls when they roll to the end of the rolling track 2-11. Speed ​​measuring devices 2-4. As a specific implementation, the speed measuring device can be an infrared speed measuring device. Specifically, the speed measuring laser head is model LB-650NMP5, and the speed is accurately measured using a laser speed measuring module sensor.

[0016] The inclined plane system 2 also includes a height adjustment device 2-3 for adjusting the angle between the inclined panel 2-1 and the bottom support plate 2-2 to obtain different slopes of the rolling track 2-11. Specifically, the height adjustment device can use a hydraulic rod of model SZ002.

[0017] To ensure that the initial velocity of the aggregate balls is zero when they roll down and that they fall to the same position each time, a launching cylinder 2-5 is provided at the front end of the rolling track 2-11. The launching cylinder 2-5 is equipped with a telescopic stop 2-51 to stop the movement of the aggregate balls. The telescopic stop 2-51 can be remotely controlled.

[0018] The test chamber 1 is equipped with a heating device 1-1 to provide a heat source for controlling the internal temperature of the test chamber 1. A blower motor 1-2 and an exhaust port 1-3 are also installed on the top wall of the test chamber 1. The blower motor 1-2 and the exhaust port 1-3 are used to regulate the temperature inside the test chamber 1. When the temperature inside the test chamber 1 is too high, the blower motor 1-2 and the exhaust port 1-3 are turned on to carry the hot gas out of the test chamber 1, achieving a rapid cooling effect.

[0019] As a specific implementation plan, the test chamber 1 adopts a heat-insulating structure and materials, and a transparent tempered glass window can be installed on the door of the test chamber 1 for real-time viewing of the test situation inside the chamber. Example 2

[0020] Based on the system for evaluating asphalt-aggregate adhesion in Example 1, the present invention provides a method for evaluating asphalt-aggregate adhesion, the method comprising the following steps: S1 heats the asphalt to a fluid state and slowly injects it back and forth into one of the rolling tracks 2-11 of the inclined plane system 2. After cooling at room temperature for 30 minutes, the asphalt film is smoothed with a hot scraper. No asphalt film is placed in the other rolling track 2-11 of the same inclined plane system 2. As a preferred embodiment, the thickness of the asphalt film is 0.1 mm.

[0021] S2 Place small aggregate balls of the same diameter and material into the launching tubes 2-5 of the two rolling tracks 2-11, and adjust the height adjustment device 2-3 to make the inclined plane angle of the rolling track 2-11 reach the preset angle; S3 Place the inclined plane system 2 into the test chamber 1, and control the temperature inside the test chamber 1 at 100℃ for 1 hour; S4 simultaneously retracts the telescopic stops 2-51 on both ball-launching cylinders 2-5, causing the aggregate balls to roll downwards from a stationary state. S5 When the aggregate balls roll to the end of the rolling track 2-11, the speed of the two aggregate balls is measured by the speed measuring device 2-4. and ; S6 calculates the lost kinetic energy. ; in, The energy lost is kinetic energy; m is the mass of the aggregate pellets; The speed at which the aggregate balls roll down the smooth rolling track 2-11 to the bottom; The speed at which the aggregate balls roll down the asphalt-coated rolling track 2-11 to the bottom.

[0022] S7 determines the adhesion level based on the magnitude of kinetic energy loss. During the rolling of aggregate balls on the surface of the asphalt film, the kinetic energy loss mainly comes from the adhesion resistance of the asphalt to the aggregate, i.e., the interfacial adhesion force. The greater the kinetic energy loss, the greater the resistance and the stronger the adhesion.

[0023] When the loss kinetic energy is 1300~2000J·10 -5 At this time, the adhesion grade is 5, which means that the asphalt has extremely strong adhesion to the aggregate, is not easy to peel off, and is suitable for heavy loads and harsh environments. When the loss kinetic energy is 700~1300J·10 -5 At this time, the adhesion grade is 4, which means that the asphalt has strong adhesion to the aggregate, good durability and anti-stripping performance, and meets the needs of most road engineering projects. When the loss of kinetic energy is 400~700J·10 -5 When the adhesion grade is 3, it means that the adhesion of asphalt to aggregate is average, the bond between aggregate and asphalt is not stable enough, and adhesion is prone to decline in humid environments. When the loss of kinetic energy is 200~400 J·10 -5 At this time, the adhesion grade is 2, which means that the adhesion of asphalt to aggregate is weak and asphalt peeling is likely to occur. When the lost kinetic energy is 0~200J·10 -5 At this point, the adhesion grade is 1, which means that the asphalt has almost no effective adhesion to the aggregate, making it extremely susceptible to water damage and structural failure, and therefore unsuitable for engineering projects. Example 3

[0024] The apparatus in Example 1 and the method in Example 2 were used to test basalt aggregate, limestone aggregate and granite aggregate on different asphalt. During the test, the slope angle of the rolling track (2-11) was 30° and the diameter of the basalt aggregate balls was 10 mm.

[0025] The test results are shown in Tables 1-3: Table 1 Test Results of Basalt Aggregates Table 2. Test results of limestone aggregates Table 3 Test Results of Granite Aggregates Comparative Example 1 Comparative Example 1 used aggregates of the same material as in Example 3. The traditional asphalt-aggregate adhesion test method in T 0616-1993 of the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering (JTGE20-2011)" was used to test the adhesion. The test results are shown in Table 4.

[0026] Table 4. Results of the boiling water test (adhesion level) Comparative Example 2 Comparative Example 2 used aggregates of the same material as in Example 3, and tested the adhesion between the asphalt and aggregate interface through a pull-out test. The specific steps are as follows: Step 1: Use ultrasonic cleaning to clean materials such as stone slabs, augers, and spatulas. After cleaning, place them in an oven and heat for 2 hours, heating the asphalt to a fluid state.

[0027] Step 2: Place a stone slab and silicone ring on a flat table, drip in asphalt and place the auger flat on the asphalt. Press lightly to make the asphalt flow evenly. After the asphalt fills the groove of the auger, press firmly and apply pressure with 3 stone slabs to keep the interface stable.

[0028] Step 3: After cooling for 1 hour, remove the weighting stone slab, remove the silicone ring, scrape off the excess asphalt with a curved scraper, and place it in a 25℃ curing box for 24 hours.

[0029] Step 4: After placing the sample in a 25℃ constant temperature chamber for 1 hour, a pull-out test was performed on the sample at a rate of 0.7MPa / s using a PosiTest AT-A fully automatic digital display pull-out adhesion tester. The test results are shown in Table 5 below.

[0030] Table 5 Pull-out test results (MPa) Based on the test results of Comparative Example 1 and Example 3, Figure 5 The comparison shows that the adhesion grade obtained by using the system and method of this patent invention is almost identical to the result obtained by the traditional boiling water method, achieving the same effect. Furthermore, the system of this invention can measure the loss of kinetic energy, effectively making up for the deficiency of traditional asphalt-aggregate adhesion testing methods that cannot be quantified.

[0031] Based on the test results of Comparative Example 2 and Example 3, Figures 6-8 The comparison shows that the loss kinetic energy measured by the system and method of the present invention has the same trend as the pull-out strength measured by the pull-out test, indicating that the system and method of the present invention can achieve the effect of accurately testing the adhesion of asphalt-aggregate.

[0032] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A system for evaluating asphalt-aggregate adhesion, characterized in that, It includes the test body box (1) and the inclined plane system (2) for the aggregate balls to roll off; The inclined plane system (2) includes an inclined panel (2-1) and a bottom support plate (2-2) hinged to the inclined panel (2-1); the inclined panel (2-1) is provided with a plurality of rolling tracks (2-11) for setting asphalt film; the walls of the rolling tracks (2-11) are provided with a mechanism for obtaining the speed of the aggregate balls when they roll to the end of the rolling track (2-11). Speed ​​measuring devices (2-4).

2. The system for evaluating asphalt-aggregate adhesion according to claim 1, characterized in that, The inclined system (2) also includes a height adjustment device (2-3) for adjusting the angle between the inclined panel (2-1) and the bottom support plate (2-2) to obtain different slopes of the rolling track (2-11).

3. The system for evaluating asphalt-aggregate adhesion according to claim 1, characterized in that, A ball launching tube (2-5) is provided at the front end of the rolling track (2-11) to make the initial velocity of the aggregate balls zero when they fall and to make the position of each fall the same. A telescopic stop (2-51) is provided on the ball launching tube (2-5) to stop the movement of the aggregate balls.

4. The system for evaluating asphalt-aggregate adhesion according to claim 1, characterized in that, The test main body box (1) is equipped with a heating device (1-1) for providing a heat source for controlling the inside of the test main body box (1). The top wall of the test main body box (1) is also equipped with a blower motor (1-2) and an exhaust port (1-3).

5. A method for evaluating asphalt-aggregate adhesion, characterized in that, Use the system according to any one of claims 1-4.

6. The method for evaluating asphalt-aggregate adhesion according to claim 5, characterized in that, The method includes the following steps: S1 heats the asphalt to a fluid state and slowly injects it back and forth into one of the rolling tracks (2-11) of the inclined plane system (2), cools it at room temperature for 30 minutes, and then smooths the asphalt film with a hot scraper; no asphalt film is placed in the other rolling track (2-11) of the same inclined plane system (2); S2 Place small aggregate balls of the same diameter and material into the launching tube (2-5) of the two rolling tracks (2-11), and adjust the height adjustment device (2-3) so that the slope angle of the rolling track (2-11) reaches the preset angle; S3 Place the inclined plane system (2) into the test body box (1), and control the temperature inside the test body box (1) at 100℃ for 1 hour; S4 simultaneously retracts the telescopic stops (2-51) on both ball-launching cylinders (2-5), causing the aggregate balls to roll downwards from a stationary state; S5 When the aggregate balls roll to the end of the rolling track (2-11), the speed of the two aggregate balls is measured by the speed measuring device (2-4). and ; S6 calculates the lost kinetic energy. ; in, The energy lost is kinetic energy; m is the mass of the aggregate pellets; The speed at which the aggregate balls roll down to the bottom on the smooth rolling track (2-11); The speed at which the aggregate balls roll down to the bottom of the asphalt-coated rolling track (2-11). 7.S7 Determine the adhesion level based on the magnitude of the lost kinetic energy.

8. The method for evaluating asphalt-aggregate adhesion according to claim 6, characterized in that, Step S7, determining the adhesion level based on the magnitude of lost kinetic energy, is as follows: When the loss kinetic energy is 1300~2000J·10 -5 At this time, the adhesion grade is 5, which means that the asphalt has extremely strong adhesion to the aggregate, is not easy to peel off, and is suitable for heavy loads and harsh environments. When the loss kinetic energy is 700~1300J·10 -5 At this time, the adhesion grade is 4, which means that the asphalt has strong adhesion to the aggregate, good durability and anti-stripping performance, and meets the needs of most road engineering projects. When the loss of kinetic energy is 400~700J·10 -5 When the adhesion grade is 3, it means that the adhesion of asphalt to aggregate is average, the bond between aggregate and asphalt is not stable enough, and adhesion is prone to decline in humid environments. When the loss of kinetic energy is 200~400 J·10 -5 At this time, the adhesion grade is 2, which means that the adhesion of asphalt to aggregate is weak and asphalt peeling is likely to occur. When the lost kinetic energy is 0~200J·10 -5 At this point, the adhesion grade is 1, which means that the asphalt has almost no effective adhesion to the aggregate, making it extremely susceptible to water damage and structural failure, and therefore unsuitable for engineering projects.

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