Enhanced asphalt mixture Marshall compaction test tamping device and method

Abstract

The invention relates to the technical field of engineering test equipment, in particular to an enhanced asphalt mixture Marshall compaction test tamping device and method. The tamping device comprises a tamping barrel, a tamping piece and a driving assembly; a tamping cavity used for being filled with an asphalt mixture is formed in the tamping barrel, a material scraping lubricating plate is arranged in the tamping cavity, holes are formed in the material scraping lubricating plate, and the holes comprise a material scraping hole and a lubricating hole; the tamping piece comprises a pressing plate and a plurality of tamping rods, and the tamping rods are all installed on the bottom side of the pressing plate and connected into the holes of the scraping lubricating plate in a penetrating mode. The driving assembly is installed outside the tamping barrel and used for driving the tamping piece to reciprocate in the axial direction of the tamping cavity so as to tamp the asphalt mixture. The tamping device ensures that a mixture is uniformly distributed in a test mold before being compacted, guarantees the volume index and mechanical property stability of a formed test piece, and improves the reliability of test data.

Description

Technical Field

[0001] This invention relates to the field of engineering testing equipment technology, and in particular to a tamping device and method for a Marshall compaction test of reinforced asphalt mixtures. Background Technology

[0002] In the field of highway engineering testing equipment, the Marshall compaction test for asphalt mixtures is a crucial step in preparing standard specimens to evaluate their volumetric properties and mechanical properties. This test typically involves loading heated asphalt mixtures into a standard Marshall mold and then impacting it with a compaction hammer. Before compaction, the mixture in the mold needs to be manually tamped to eliminate coarse aggregate segregation and improve internal uniformity, providing a good initial condition for subsequent compaction. This is an important prerequisite for obtaining reliable test data.

[0003] Currently, before Marshall compaction, operators in the industry use handheld tools such as trowels or large screwdrivers to tamp the hot asphalt mixture placed in the Marshall mold in layers. Because it is entirely manual, the tamping points, depths, and forces are highly random. Especially in the edge areas of the mold, it is difficult for the tools to maintain a vertical and uniform cut, resulting in inconsistent compaction effects in these areas compared to the central areas. This can easily create density gradients within the specimen, directly affecting the uniformity and representativeness of volumetric indicators such as porosity in the final specimen.

[0004] Secondly, for high-viscosity specialty mixtures such as RPC rubber-plastic composite reinforced compounds, the resistance during manual tamping is high, leading to prolonged operation time. The increased exposure time of the hot mixture to air accelerates heat loss, and since the viscosity of the mixture is extremely sensitive to temperature, a drop in temperature further increases the difficulty of tamping and alters its working properties, causing the conditions of the molded specimens to deviate from standard requirements and reducing the reliability of the test results.

[0005] In addition, the mixture is very easy to adhere to the surface of the metal tamping tool, which not only increases the resistance of each tamping and affects the feel and force control of the operator, but also accumulates continuously during continuous operation. In the prior art, the workpiece needs to be dipped in lubricating oil before tamping with the tool, which reduces the work efficiency. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this invention is to provide a tamping device and method for an enhanced asphalt mixture Marshall compaction test, ensuring uniform distribution of the mixture within the mold before compaction, guaranteeing stable volumetric and mechanical properties of the molded specimens, and improving the reliability of test data.

[0007] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0008] A tamping device for an enhanced asphalt mixture Marshall compaction test includes: a tamping bucket, a tamping element, and a drive assembly; the tamping bucket has a tamping chamber for filling the asphalt mixture, and a scraper lubricating plate is provided in the tamping chamber, the scraper lubricating plate having holes, the holes including scraper holes and lubrication holes; the tamping element includes a pressure plate and multiple tamping rods, all of which are installed on the bottom side of the pressure plate and pass through the holes in the scraper lubricating plate; the drive assembly is installed outside the tamping bucket and is used to drive the tamping element to reciprocate along the axial direction of the tamping chamber to tampe the asphalt mixture.

[0009] Optionally, the tamping bucket has a cylindrical structure, and the pressure plate is a circular plate that can move along the cavity wall of the tamping chamber.

[0010] Optionally, the scraper hole is located on the lower side for scraping off asphalt mixture adhering to the tamping rod, and the lubrication hole is located on the upper side for applying lubricating oil to the outer wall of the tamping rod.

[0011] Optionally, the scraping hole is a cylindrical hole, and the lubrication hole is a conical hole, wherein the upper diameter of the conical hole is larger than the lower diameter, and the lower diameter of the conical hole is equal to the diameter of the cylindrical hole.

[0012] Optionally, the scraper lubricating plate has an oil cavity, the outer wall of the scraper lubricating plate has an oil inlet hole communicating with the oil cavity, and the wall of the lubrication hole is provided with an oil injection hole communicating with the oil cavity.

[0013] Optionally, a plurality of oil injection holes are provided, and the plurality of oil injection holes are arranged in a circumferential array along the axis of the vibrating rod.

[0014] Optionally, the tamping component further includes a connecting rod, the lower end of which is connected to the pressure plate, and the upper end of which is connected to the drive assembly.

[0015] Optionally, the drive assembly includes a bracket and a pressure rod. The bracket is fixed to the outer wall of the tamping barrel, and the pressure rod is rotatably mounted on the bracket. One end of the pressure rod is rotatably connected to the connecting rod, and the lower end of the connecting rod is rotatably connected to the pressure plate.

[0016] Optionally, an angle sensor is also installed on the bracket, and the rotation shaft of the angle sensor is coaxially connected with the rotation shaft of the pressure rod to detect the rotation direction of the pressure rod relative to the bracket.

[0017] This invention also provides a compaction method for the reinforced asphalt mixture Marshall compaction test compaction device as described above, comprising: The drive assembly drives the tamping component to reciprocate along the axial direction within the tamping chamber, so that multiple tamping rods pass through the holes in the scraper lubrication plate to tamp the asphalt mixture. As the tamping bar moves upward, the asphalt mixture adhering to the outer surface of the tamping bar is scraped off through the scraper hole located on the lower side of the scraper lubrication plate; as the tamping bar moves downward, lubricating oil is applied to the outer surface of the tamping bar through the lubrication hole located on the upper side of the scraper lubrication plate. The rotation direction of the pressure rod relative to the support is detected by an angle sensor. When the pressure rod is detected to rotate in the set direction, the lubricating oil is controlled to be coated onto the outer surface of the tamping rod through the lubrication hole.

[0018] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages: This invention provides a mechanized tamping device for RPC (Reinforced Polymer) rubber-plastic composite mixtures. The tamping drum forms a fixed cavity that accommodates the asphalt mixture and guides the movement of the tamping components. The tamping components, acting as the execution parts, utilize a multi-component design to cover multiple areas within the mold simultaneously, replacing the manual single-point tamping method and thus improving the uniformity and efficiency of the tamping operation. Furthermore, a scraper lubrication plate is installed within the tamping cavity. The holes on the scraper lubrication plate not only guide the tamping components but also spatially combine the auxiliary functions of cleaning adhering material and applying lubricant with the main tamping action. This allows for automatic scraping and lubrication during the single up-and-down reciprocating movement of the tamping components, solving the problems of high-viscosity mixtures easily adhering to tools, affecting tamping results, and being inconvenient to clean. Therefore, this tamping device ensures tamping uniformity while reducing heat loss and mixture adhesion.

[0019] Advantages of additional aspects of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In addition, the dimensions or spacing between the components are exaggerated to show the position of each component, and the schematic diagrams are for illustrative purposes only.

[0021] Figure 1 This is a schematic diagram of the external shape of the tamping device provided in an embodiment of the present invention; Figure 2 This is a disassembly diagram of the tamping component and the scraper lubrication plate provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the scraper lubrication plate provided in an embodiment of the present invention; Figure 4This is a schematic diagram of the hole fit between the tamping rod and the scraper lubrication plate provided in an embodiment of the present invention; In the diagram: 1. Tamping bucket; 11. Scraper lubrication plate; 12. Hole; 121. Lubrication hole; 122. Oil injection hole; 123. Scraper hole; 13. Oil inlet hole; 14. Oil chamber; 2. Tamping component; 21. Connecting rod; 22. Pressure plate; 23. Tamping rod; 3. Drive assembly; 31. Pressure rod; 32. Support; Detailed Implementation It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0022] Example 1 like Figure 1 As shown, this embodiment proposes a tamping device for an enhanced asphalt mixture Marshall compaction test, characterized by comprising: a tamping bucket 1, a tamping component 2, and a driving assembly 3; the tamping bucket 1 has a tamping chamber for filling asphalt mixture, and a scraper lubrication plate 11 is provided in the tamping chamber, such as... Figure 2 , Figure 3 As shown, the scraper lubrication plate 11 has holes 12, including scraper holes 123 and lubrication holes 121; the tamping component 2 includes a pressure plate 22 and tamping rods 23, and there are multiple tamping rods 23, which are all installed on the bottom side of the pressure plate 22 and pass through the holes 12 of the scraper lubrication plate 11; the driving assembly 3 is installed outside the tamping barrel 1 and is used to drive the tamping component 2 to move back and forth along the axial direction of the tamping chamber to tamp the asphalt mixture.

[0023] The multiple tamping rods 23 can cover all areas of the tamping chamber, including the edges, solving the problem of uneven distribution caused by the difficulty of covering the edges during manual tamping. The drive assembly 3 drives the tamping component 2 to move back and forth, reducing labor intensity, shortening tamping time, reducing temperature loss from the asphalt mixture, and preventing the rapid temperature drop from damaging the structural stability of the mixture. The scraper hole 123 and the lubrication hole 121 solve the problem of the mixture sticking to the tool. The three work together to integrate the tamping, scraping, and lubrication actions, ensuring tamping uniformity while reducing temperature loss and tool adhesion.

[0024] The tamping bucket 1 has a cylindrical structure, and the pressure plate 22 is a circular plate that can move along the cavity wall of the tamping chamber. The circular fit ensures that the tamping rod 23 can be inserted vertically and stably into the mixture, which is beneficial for obtaining a uniform tamping force distribution and regular specimens.

[0025] The scraper hole 123 is located on the lower side and is used to scrape off the asphalt mixture adhering to the tamping rod 23. The lubrication hole 121 is located on the upper side and is used to apply lubricating oil to the outer wall of the tamping rod 23.

[0026] The scraper hole 123 is located on the lower side, corresponding to the upward return path of the tamping rod 23. This allows the scraper to remove asphalt mixture adhering to the surface of the tamping rod 23 as it is pulled out of the mixture. The lubrication hole 121 is located on the upper side, corresponding to the downward insertion path of the tamping rod 23. This allows the tamping rod 23 to be coated with lubricating oil on its outer wall before re-entering the mixture. Scraping away residual material during upward movement maintains the cleanliness and effective diameter of the tamping rod 23. Lubrication before downward movement reduces the adhesion and insertion resistance of the mixture to the tamping rod 23 in the next cycle. Together, these two mechanisms effectively interrupt the accumulation of adhesion, ensuring smooth tamping action and consistent force.

[0027] like Figure 3 , Figure 4 As shown, the scraper hole 123 is a cylindrical hole, the lubrication hole 121 is a conical hole, the upper diameter of the conical hole is larger than the lower diameter, the lower diameter of the conical hole is equal to the diameter of the cylindrical hole, and the oil injection hole 122 is provided on the hole wall of the lubrication hole 121.

[0028] The lubrication hole 121 is a conical hole that is larger at the top and smaller at the bottom. Its lower end diameter is equal to that of the cylindrical hole. The oil injection hole 122 is set on the wall of the conical hole. Even if there is a small amount of residual material on the surface of the tamping rod 23 that has not been completely scraped off, it will not block the oil injection hole 122, thus ensuring the long-term operation of the lubrication function.

[0029] The scraper lubrication plate 11 has an oil cavity 14 inside, and the outer wall of the scraper lubrication plate 11 has an oil inlet hole 13 that communicates with the oil cavity 14. The oil injection hole 122 communicates with the oil cavity 14.

[0030] As the tamping rod 23 moves downwards through the lubrication hole 121, its surface comes into contact with the area of ​​the oil injection hole 122. Lubricating oil seeps out through the oil injection hole 122 and is thus coated on the surface of the tamping rod 23. The lubricating oil used is a conventional industrial lubricating oil (non-hydrocarbon modified oil) with weak compatibility with asphalt, and the amount used is extremely small, so its impact on the overall density of the mixture is within the allowable error range of the test.

[0031] Several oil injection holes 122 are provided, and the several oil injection holes 122 are arranged in a circumferential array along the axis of the vibrating rod. Oil is supplied to the outer surface of the passing tamping rod 23 from multiple points on the inner circumferential direction of the lubrication hole 121, ensuring that the lubricating oil can be evenly coated on the entire circumferential surface of the tamping rod 23, and avoiding uneven lubrication caused by single-point oil supply.

[0032] The tamping component 2 also includes a connecting rod 21, the lower end of which is connected to the pressure plate 22, and the upper end of which is connected to the drive assembly 3. The connecting rod 21 serves to connect and transmit power, transferring the motion and force generated by the drive assembly 3 to the pressure plate 22, thereby driving all the tamping rods 23 to move synchronously.

[0033] The drive assembly 3 includes a bracket 32 ​​and a pressure rod 31. The bracket 32 ​​is fixed on the outer wall of the tamping bucket 1. The pressure rod 31 is rotatably mounted on the bracket 32. One end of the pressure rod 31 is rotatably connected to the connecting rod 21, and the lower end of the connecting rod 21 is rotatably connected to the pressure plate 22.

[0034] The pressure rod 31 is rotatably mounted on the bracket 32, forming a lever structure. One end of the pressure rod 31 is rotatably connected to the connecting rod 21. When the operator presses down on the other end of the pressure rod 31, the pressure rod 31 rotates around the fulcrum on the bracket 32, amplifying the force and motion through the connecting rod 21 and transmitting it to the tamping component 2. The structure is simple and reliable, requires no electricity, and through the principle of mechanical amplification, allows the operator to drive the tamping rod 23 with a small force to overcome the resistance of the high-viscosity mixture, achieving labor-saving operation.

[0035] An angle sensor is also installed on the bracket 32. The rotation shaft of the angle sensor is coaxially connected to the rotation shaft of the pressure rod 31. It is used to detect the rotation direction of the pressure rod 31 relative to the bracket 32, and thus determine whether the tamping rod 23 is currently in the downward insertion stroke or the upward lifting stroke. For example, when it is detected that the pressure rod 31 rotates counterclockwise relative to the bracket 32, that is, the tamping rod 23 moves downward, the lubrication action is triggered.

[0036] Example 2 This embodiment provides a compaction method for an enhanced asphalt mixture Marshall compaction test compaction device, including: The drive assembly 3 drives the tamping component 2 to reciprocate along the axial direction in the tamping chamber, so that multiple tamping rods 23 pass through the holes 12 on the scraper lubrication plate 11 to tampe the asphalt mixture. As the tamping rod 23 moves upward, the asphalt mixture adhering to the outer surface of the tamping rod 23 is scraped off through the scraping hole 123 located on the lower side of the scraping lubrication plate 11; as the tamping rod 23 moves downward, lubricating oil is applied to the outer surface of the tamping rod 23 through the lubrication hole 121 located on the upper side of the scraping lubrication plate 11. The rotation direction of the pressure rod 31 relative to the bracket 32 ​​is detected by the angle sensor. When the pressure rod 31 is detected to rotate in the set direction, the lubricating oil is controlled to be coated onto the outer surface of the tamping rod 23 through the lubrication hole 121.

[0037] The tamping component 2 is driven by the drive assembly 3 to reciprocate, thus completing the basic tamping function. The scraping action is linked to the upward movement process, and the lubrication action is linked to the downward movement process, forming a maintenance process that is automatically synchronized with the mechanical movement rhythm. Based on the trigger control logic of the angle sensor detection results, the supply of lubricating oil is associated with the downward pressing action of the pressure rod 31, realizing condition-triggered intelligent lubrication.

[0038] The three actions of tamping, scraping, and lubrication are carried out in a coordinated manner, which shortens the total time of tamping operations, reduces the temperature loss of asphalt mixtures, ensures the structural stability of the mixtures, and thus improves the accuracy and reliability of test data.

[0039] This method is applicable to the compaction treatment of high-viscosity asphalt mixtures such as RPC rubber-plastic composite reinforced mixtures before Marshall compaction tests. For example, in the mix design stage of highway engineering asphalt mixtures, using this method to compact the mixture before Marshall compaction molding can obtain specimens with better uniformity.

[0040] While the specific embodiments of the present invention have been described above, they are not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A tamping device for a Marshall compaction test of reinforced asphalt mixtures, characterized in that, include: Tamping bucket, tamping components, and drive assembly; The tamping bucket has a tamping chamber for filling asphalt mixture. The tamping chamber is equipped with a scraper lubricating plate. The scraper lubricating plate has holes, including scraping holes and lubrication holes. The tamping component includes a pressure plate and tamping rods. There are multiple tamping rods, all of which are installed on the bottom side of the pressure plate and pass through the holes of the scraper lubrication plate. The drive assembly is installed outside the tamping barrel and is used to drive the tamping component to move back and forth along the axial direction of the tamping chamber to tamp the asphalt mixture.

2. The reinforced asphalt mixture Marshall compaction test tamping device as described in claim 1, characterized in that, The tamping bucket has a cylindrical structure, and the pressure plate is a circular plate that can move along the cavity wall of the tamping chamber.

3. The reinforced asphalt mixture Marshall compaction test tamping device as described in claim 1, characterized in that, The scraper hole is located on the lower side and is used to scrape off the asphalt mixture adhering to the tamping rod. The lubrication hole is located on the upper side and is used to apply lubricating oil to the outer wall of the tamping rod.

4. The tamping device for the Marshall compaction test of reinforced asphalt mixture as described in claim 3, characterized in that, The scraping hole is a cylindrical hole, and the lubrication hole is a conical hole. The upper diameter of the conical hole is larger than the lower diameter, and the lower diameter of the conical hole is equal to the diameter of the cylindrical hole.

5. The reinforced asphalt mixture Marshall compaction test tamping device as described in claim 4, characterized in that, The scraper lubricating plate has an oil cavity inside, and the outer wall of the scraper lubricating plate has an oil inlet hole communicating with the oil cavity. The wall of the lubrication hole is provided with an oil injection hole communicating with the oil cavity.

6. The tamping device for the Marshall compaction test of reinforced asphalt mixture as described in claim 5, characterized in that, Several oil injection holes are provided, and these oil injection holes are arranged in a circular array along the axis of the vibrating rod.

7. The reinforced asphalt mixture Marshall compaction test tamping device as described in claim 1, characterized in that, The tamping component also includes a connecting rod, the lower end of which is connected to the pressure plate, and the upper end of which is connected to the drive assembly.

8. The tamping device for the Marshall compaction test of reinforced asphalt mixture as described in claim 7, characterized in that, The drive assembly includes a bracket and a pressure rod. The bracket is fixed to the outer wall of the tamping barrel, and the pressure rod is rotatably mounted on the bracket. One end of the pressure rod is rotatably connected to the connecting rod, and the lower end of the connecting rod is rotatably connected to the pressure plate.

9. The tamping device for the Marshall compaction test of reinforced asphalt mixture as described in claim 8, characterized in that, An angle sensor is also installed on the bracket. The rotation shaft of the angle sensor is coaxially connected with the rotation shaft of the pressure rod to detect the rotation direction of the pressure rod relative to the bracket.

10. A compaction method for a reinforced asphalt mixture Marshall compaction test compaction device as described in any one of claims 1-9, characterized in that, include: The drive assembly drives the tamping component to reciprocate along the axial direction within the tamping chamber, so that multiple tamping rods pass through the holes in the scraper lubrication plate to tamp the asphalt mixture. As the tamping bar moves upward, the asphalt mixture adhering to the outer surface of the tamping bar is scraped off through the scraper hole located on the lower side of the scraper lubrication plate; as the tamping bar moves downward, lubricating oil is applied to the outer surface of the tamping bar through the lubrication hole located on the upper side of the scraper lubrication plate. The rotation direction of the pressure rod relative to the support is detected by an angle sensor. When the pressure rod is detected to rotate in the set direction, the lubricating oil is controlled to be coated onto the outer surface of the tamping rod through the lubrication hole.

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