Rolling device for measuring loose paving coefficient of asphalt pavement and loose paving coefficient measuring method

Abstract

The invention relates to the field of bituminous pavement construction parameter testing, in particular to a bituminous pavement loose paving coefficient measuring rolling device and a loose paving coefficient measuring method.The measuring rolling device comprises a rack and a test mold, a loading frame is arranged in the rack, and a rolling steel wheel and a rolling rubber wheel are arranged at the two ends of the loading frame respectively; an overturning shaft is arranged in the middle of the loading frame, the two ends of the overturning shaft are rotationally connected to corresponding sliding blocks respectively, the two sliding blocks are slidably connected to sliding grooves preset in the left side and the right side of the rack, and one sliding block is connected with a reciprocating driving device; the test mold is an uncovered rectangular hollow box and is used for forming a test piece. A reasonable loose paving coefficient can be provided for paving of an asphalt pavement test road through a test, on the basis, the paving thickness control of the test road and the non-test road is more accurate, the pavement height difference of the test road and the non-test road is further reduced, and the pavement quality of the test road and the non-test road is improved. The method effectively solves the problem that the loose paving coefficient in asphalt pavement construction is mostly determined by experience and is lack of scientific basis.

Description

Technical Field

[0001] The invention relates to the field of asphalt pavement construction parameter testing, and in particular to a loose paving coefficient determination roller device and a loose paving coefficient determination method for an asphalt pavement. Background Art

[0002] Asphalt pavement is a single-layer or multi-layer structure formed by paving and rolling asphalt mixture on the roadbed. It has the functions of bearing and spreading vehicle loads, resisting wear, avoiding dust and keeping the road surface flat. The thickness of each structural layer in the construction of asphalt pavement surface layer is a key link in the quality control of asphalt pavement. In the "Highway Engineering Quality Inspection and Assessment Standards", the thickness of the asphalt surface layer is also a key item for assessing the quality of asphalt pavement.

[0003] At present, in asphalt pavement construction, the thickness of each structural layer of the asphalt pavement surface layer is mainly determined by its paving thickness, and the paving thickness can be determined by the loose paving coefficient (the loose paving coefficient is the ratio of the loose paving thickness to the compacted thickness of the specified compaction degree). In actual production practice, the loose paving coefficient is determined in the form of paving test roads, according to the degree of proximity between the compacted thickness of each structural layer of the test road paved under different loose paving coefficients (here the loose paving coefficient is determined by experience) and the design thickness of the corresponding layer. As a result, there is inevitably a slight height difference between different test sections and between them and non-test roads due to the different loose paving coefficients adopted. In addition, different layers of asphalt pavements have different requirements for materials due to their different functions. The surface structural layers of asphalt pavements usually use different materials (such as: base asphalt mixture, modified asphalt mixture, high-viscosity and high-elastic asphalt mixture, etc.) based on performance requirements. There are significant differences in the workability of different types of asphalt mixtures, and their loose paving coefficients are also significantly different. Therefore, proposing a scientific and reasonable loose paving coefficient for different mixtures during test road paving has important practical significance for controlling the paving thickness of asphalt pavement and reducing thickness errors.

[0004] In view of the above-mentioned problems, in the prior art, patent CN104746414A proposes a remote real-time monitoring method based on a network cloud platform that integrates paving thickness, construction temperature and GPS positioning, realizing digital management of the asphalt pavement construction process to improve the construction quality of the asphalt pavement. Patent CN 117026744A has developed an asphalt pavement paving thickness detection system, which realizes real-time adjustment of the pavement paving thickness by setting a height detection device before and after the ironing plate. Patent CN109162183A has developed an asphalt pavement paving thickness calculation model and real-time measurement equipment, which monitors the paving thickness of the asphalt pavement in real time through a measurement system that spans the paved section and the unpaved section. Patent CN220704271U proposes a method for controlling the paving thickness of the asphalt pavement by drawing contour lines between the paved section and the unpaved section. Comprehensive analysis shows that the above patents mainly explore the process control of asphalt pavement paving, and have not yet attracted attention to the determination of loose paving thickness and the prediction of loose paving coefficient in asphalt pavement construction.

[0005] From the above, we can see that the determination of the loose paving coefficient in asphalt pavement construction lacks a scientific basis and is mostly determined by experience, resulting in a certain height difference between the test road and the non-test road. In addition, the existing patents have not yet conducted an effective exploration of the determination of the loose paving coefficient. Therefore, it is currently urgent to develop a roller pressing device for measuring the loose paving coefficient of asphalt pavement and a method for measuring the loose paving coefficient, so as to provide a scientific and reasonable loose paving coefficient for the paving of asphalt pavement test roads. On this basis, a more accurate loose paving coefficient can be determined by paving the test road, so that the paving thickness control of the test road and the non-test road can be more accurate, thereby reducing the height difference between the test road and the non-test road. Summary of the invention

[0006] Based on the above problems, the purpose of the present invention is to provide a roller pressing device for measuring the loose paving coefficient of asphalt pavement and a method for measuring the loose paving coefficient. The present invention adopts the following technical solutions:

[0007] The present invention provides a roller compaction device for measuring the loose paving coefficient of an asphalt pavement, comprising:

[0008] A frame, wherein a loading frame is arranged in the frame, and roller steel wheels and roller rubber wheels are arranged at two ends of the loading frame respectively, and a turning shaft is arranged in the middle of the loading frame, and the two ends of the turning shaft are rotatably connected to corresponding sliders respectively, and the two sliders are slidably connected to the preset slide grooves on the left and right sides of the frame, and one of the sliders is connected to the reciprocating drive device;

[0009] A specimen installation platform is located below the loading frame. A test mold is arranged on the top of the specimen installation platform. The test mold is a hollow rectangular box without a cover and is used for molding the specimen.

[0010] Preferably, a steering power motor is provided on one of the sliding blocks, and a rotating shaft of the steering power motor is connected to the flip shaft.

[0011] Preferably, the reciprocating drive device includes a rolling power motor, which is arranged on the frame. A turntable is arranged on the rotating shaft of the rolling power motor, and a driving rod is arranged on one side of the turntable. One end of the driving rod is rotatably connected to a non-center position of the turntable, and the other end is rotatably connected to the corresponding slider.

[0012] Preferably, the specimen mounting platform includes a bearing plate, and a plurality of pressure compensators are arranged at the bottom of the bearing plate, and the pressure compensators are used to provide a constant lifting pressure for the specimen mounting platform to ensure that the wheel pressure to which the specimen is subjected during the rolling process is constant; a vibrator is fixed to the bottom surface of the bearing plate, and the vibrator is used to generate vibration for the specimen mounting platform.

[0013] Preferably, the pressure compensator comprises a telescopic driving member, and the top of the telescopic driving member is in contact with the bearing plate through a pressure sensor.

[0014] Preferably, the number of the rolled steel wheel is one and the shape is cylindrical; the number of the rolled rubber wheels is multiple and they are combined in series at intervals; and the loading frame is X-shaped.

[0015] Preferably, handles are provided on two opposite sides of the trial mold.

[0016] The present invention provides a method for determining the loose paving coefficient of an asphalt pavement, which is characterized by comprising the following steps:

[0017] Step 1: Fill the test mold with fresh asphalt mixture from the edge to the middle and compact it with a tamping rod, then use a scraper to scrape the asphalt mixture along the surface of the test mold, and then use a preheated electric iron to iron the asphalt mixture.

[0018] Step 2: quickly move the test mold with the prepared sample to the test piece installation platform and start the test; turn on the vibrator, and then use the roller steel wheel to repeatedly roll the asphalt mixture 2 to 4 times, turn off the vibrator, and then use the roller rubber wheel to repeatedly roll the asphalt mixture 8 to 12 times, and then use the roller steel wheel to repeatedly roll the asphalt mixture 2 to 4 times;

[0019] Step 3: After the test is finished, take out the test mold and pour out the test piece, and measure the density of the compacted asphalt mixture test piece by using a nuclear density meter method;

[0020] Step 4: Calculate the compaction degree K of the asphalt mixture specimen according to the measured density ρ1 of the compacted asphalt mixture specimen and the maximum theoretical density ρ2 of the asphalt mixture according to the following formula;

[0021] K = ρ1 / ρ2 × 100%;

[0022] Step 5: Repeat steps 1 to 4 until the specified compaction degree of the asphalt pavement is obtained. The loose laying coefficient S of the asphalt mixture is calculated according to the following formula based on the measured test piece height h1 compacted to the specified compaction degree and the test mold loading height h2;

[0023] S=h1 / h2.

[0024] Compared with the prior art, the beneficial technical effects of the present invention are:

[0025] The present invention provides a roller pressing device for determining the loose paving coefficient of an asphalt pavement and a method for determining the loose paving coefficient, which provide a scientific and reasonable loose paving coefficient for paving a test road of an asphalt pavement. On this basis, a more accurate loose paving coefficient is determined by paving the test road, so that the paving thickness control of the test road and the non-test road is more accurate, thereby reducing the road surface height difference between the test road and the non-test road, effectively solving the problem that the loose paving coefficient in asphalt pavement construction is mostly determined by experience and lacks a scientific basis, and filling a gap in the technical field of asphalt pavement construction parameter testing equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described below in conjunction with the accompanying drawings.

[0027] Figure 1 It is a side structural schematic diagram of a roller compaction device for measuring loose paving coefficient of asphalt pavement in an embodiment of the present invention;

[0028] Figure 2 It is a schematic diagram of the top view of the structure of the roller compaction device for measuring the loose paving coefficient of the asphalt pavement in an embodiment of the present invention;

[0029] Figure 3 It is a schematic diagram of the main structure of the rolling device for measuring the loose paving coefficient of asphalt pavement in an embodiment of the present invention;

[0030] Figure 4 It is a schematic diagram of the action process of the reciprocating drive device in an embodiment of the present invention;

[0031] Figure 5 Schematic diagram of the switching process between the rolled steel wheel and the rolled rubber wheel in an embodiment of the present invention;

[0032] Figure 6 It is a structural schematic diagram of a test piece installation platform in an embodiment of the present invention;

[0033] Figure 7 Schematic diagram of the structure of the pressure compensator in an embodiment of the present invention.

[0034] Explanation of the reference numerals in the accompanying drawings: 1. Frame; 2. Loading frame; 3. Rolled steel wheel; 4. Rolled rubber wheel; 5. Flip shaft; 6. Slider; 7. Reciprocating drive device; 701. Rolling power motor; 702. Turntable; 703. Drive rod; 8. Test piece mounting platform; 801. Loading plate; 802. Vibrator; 803. Pressure compensator; 803-1. Telescopic drive member; 803-2. Pressure sensor; 9. Test mold; 901. Handle; 10. Steering power motor. DETAILED DESCRIPTION

[0035] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0036] like Figures 1 to 5 As shown, this embodiment discloses a roller pressing device for measuring the loose paving coefficient of asphalt pavement, including a frame 1, which is a rectangular box structure, with four sides of the upper, lower, left and right sides being fixed rectangular frames, the front and rear sides being detachable, and a slide groove being provided in the middle of the left and right sides in the horizontal direction. It mainly provides a loading platform for the installation of various components.

[0037] A loading frame 2 is arranged in the frame 1, and a rolled steel wheel 3 and a rolled rubber wheel 4 are arranged at both ends of the loading frame 2 respectively. A turning shaft 5 is arranged in the middle of the loading frame 2, and both ends of the turning shaft 5 are rotatably connected to corresponding sliders 6 respectively, and the two sliders 6 are slidably connected in the preset slide grooves on the left and right sides of the frame 1.

[0038] A steering power motor 10 is provided on one of the sliders 6, and the rotating shaft of the steering power motor 10 is connected to the flip shaft 5, and the other slider 6 is connected to the reciprocating drive device 7. The reciprocating drive device 7 drives the slider 6 to make reciprocating linear motion, thereby driving the loading frame 2 to make reciprocating linear motion. The loading frame 2 can be rotated around the flip shaft 5 by the steering power motor 10 to realize the switching of the rolling steel wheel 3 and the rolling rubber wheel 4 during the rolling process. In this embodiment, the steering power motor 10 is arranged on the slider 6 on the left side, and the slider 6 on the right side is connected to the reciprocating drive device 7, so that the steering power motor 10 can be prevented from interfering with the reciprocating drive device 7, and the sliders 6 on both sides are fully utilized.

[0039] like Figure 2 As shown, the reciprocating drive device 7 includes a rolling power motor 701, which is arranged on the frame 1. A turntable 702 is arranged on the rotating shaft of the rolling power motor 701. A driving rod 703 is arranged on one side of the turntable 702. One end of the driving rod 703 is rotatably connected to a non-center position of the turntable 702, and the other end is rotatably connected to the corresponding slider 6.

[0040] like Figure 1As shown, the specimen installation platform 8 is arranged in the frame 1, and the specimen installation platform 8 is located below the loading frame 2. A test mold 9 is arranged on the top of the specimen installation platform 8. The test mold 9 is a hollow rectangular box without a cover and is used for specimen molding. Handles 901 are arranged on two opposite sides of the test mold 9 to facilitate the movement of the test mold 9.

[0041] like Figure 6 and 7 As shown, the specimen installation platform 8 includes a bearing plate 801, and a plurality of pressure compensators 803 are arranged at the bottom of the bearing plate 801. The pressure compensators 803 are used to provide a constant lifting pressure for the specimen installation platform 8 to ensure that the wheel pressure on the specimen during the rolling process is constant; a vibrator 802 is fixed to the bottom surface of the bearing plate 801, and the vibrator 802 is used to generate vibration for the specimen installation platform 8.

[0042] In this embodiment, the pressure compensator 803 includes a telescopic driving member 803-1, and the top of the telescopic driving member 803-1 is in contact with the bearing plate 801 through a pressure sensor 803-2. The telescopic driving member 803-1 can adjust its own height through the sensed value of the pressure sensor 803-2. The telescopic driving member 803-1 can specifically adopt an oil cylinder, which is connected to the hydraulic system. The pressure sensor 803-2 feeds back the sensing signal to the control system, and the control system regulates the operation of the hydraulic system.

[0043] In this embodiment, the number of the rolled steel wheel 3 is one, and the shape is cylindrical. The number of the rolled rubber wheel 4 is multiple, and they are combined in series at intervals. The loading frame 2 is X-shaped. Both ends of the loading frame 2 are provided with support shaft seats for mounting the rolled steel wheel 3 and the rolled rubber wheel 4.

[0044] In this embodiment, different types of sensors and displays are included. The sensors can monitor the vibration mode, speed, and number of passes of steel wheel vibration rolling, the speed and number of passes of rubber wheel rolling, the speed and number of passes of steel wheel static pressure, and the contact pressure between the rolling steel wheel / rubber wheel and the test piece, and feed back the corresponding signals to the controller. The controller displays the data on the display. The operator can set parameters on the display, and the controller can control the corresponding motor to work according to the set parameters. The sensors mainly include vibration sensors, speed sensors, counting sensors (photoelectric sensors), pressure sensors, etc.

[0045] This embodiment discloses a method for determining the loose paving coefficient of an asphalt pavement, comprising the following steps:

[0046] Step 1: Fill the test mold 9 with fresh asphalt mixture from the edge to the middle and compact it with a tamping rod, then use a scraper to scrape the asphalt mixture along the surface of the test mold 9, and then use a preheated electric iron to iron the asphalt mixture (asphalt mixture is 100°C).

[0047] Step 2: quickly move the test mold 9 with the prepared sample to the test piece installation platform 8; start the test; turn on the vibrator 802, and then use the roller steel wheel 3 to repeatedly roll the asphalt mixture 2 to 4 times, turn off the vibrator 802, and then use the roller rubber wheel 4 to repeatedly roll the asphalt mixture 8 to 12 times, and then use the roller steel wheel 3 to repeatedly roll the asphalt mixture 2 to 4 times.

[0048] Step 3: After the test is finished, take out the test mold 9 and pour out the test piece, and use the nuclear density meter method to measure the density of the compacted asphalt mixture test piece.

[0049] Step 4: Calculate the compaction degree K of the asphalt mixture specimen according to the measured density ρ1 of the compacted asphalt mixture specimen and the maximum theoretical density ρ2 of the asphalt mixture (ρ2 - known from the mix design report) according to the following formula;

[0050] K = ρ1 / ρ2 × 100%;

[0051] Step 5: Repeat steps 1 to 4 until the specified compaction degree of the asphalt pavement is obtained (generally 92% of the maximum theoretical density, where SMA is 94% of the maximum theoretical density). Calculate the loose laying coefficient S of the asphalt mixture according to the following formula based on the measured specimen height h1 compacted to the specified compaction degree and the sample loading height h2 of the test mold: S = h1 / h2.

[0052] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A rolling device for measuring the loose paving coefficient of an asphalt pavement, characterized in that: include: A frame (1), wherein a loading frame (2) is arranged in the frame (1), and roller steel wheels (3) and roller rubber wheels (4) are arranged at two ends of the loading frame (2), and a turning shaft (5) is arranged in the middle of the loading frame (2), and the two ends of the turning shaft (5) are respectively rotatably connected to corresponding sliders (6), and the two sliders (6) are slidably connected to the preset sliding grooves on the left and right sides of the frame (1), and one of the sliders (6) is connected to a reciprocating driving device (7); A specimen installation platform (8) is located below the loading frame (2). A test mold (9) is arranged on the top of the specimen installation platform (8). The test mold (9) is a hollow rectangular box without a cover and is used for molding the specimen.

2. The rolling device for measuring the loose paving coefficient of asphalt pavement according to claim 1 is characterized in that: A steering power motor (10) is provided on one of the sliding blocks (6), and a rotating shaft of the steering power motor (10) is connected to the flip shaft (5).

3. The rolling device for measuring the loose paving coefficient of asphalt pavement according to claim 1 is characterized in that: The reciprocating drive device (7) comprises a rolling power motor (701), the rolling power motor (701) is arranged on the frame (1), a turntable (702) is arranged on the rotating shaft of the rolling power motor (701), a driving rod (703) is arranged on one side of the turntable (702), one end of the driving rod (703) is rotatably connected to a non-central position of the turntable (702), and the other end is rotatably connected to the corresponding slider (6).

4. The rolling device for measuring the loose paving coefficient of asphalt pavement according to claim 1 is characterized in that: The specimen installation platform (8) comprises a bearing plate (801), a plurality of pressure compensators (803) are arranged at the bottom of the bearing plate (801), and the pressure compensators (803) are used to provide a constant lifting pressure for the specimen installation platform (8) to ensure that the wheel pressure applied to the specimen during rolling is constant; a vibrator (802) is fixed to the bottom surface of the bearing plate (801), and the vibrator (802) is used to generate vibration for the specimen installation platform (8).

5. The rolling device for measuring the loose paving coefficient of asphalt pavement according to claim 4 is characterized in that: The pressure compensator (803) comprises a telescopic driving member (803-1), and the top of the telescopic driving member (803-1) is in contact with the supporting plate (801) through a pressure sensor (803-2).

6. The rolling device for measuring the loose paving coefficient of asphalt pavement according to claim 1 is characterized in that: The number of the rolled steel wheel (3) is one and the shape is cylindrical; the number of the rolled rubber wheels (4) is multiple and they are combined in series at intervals; and the loading frame (2) is in an X shape.

7. The rolling device for measuring the loose paving coefficient of asphalt pavement according to claim 1 is characterized in that: Handles (901) are provided on two opposite sides of the trial mold (9).

8. A method for determining the loose paving coefficient of an asphalt pavement, characterized in that: The following steps are involved: Step 1: Fill the test mold (9) with fresh asphalt mixture from the edge to the middle and compact it with a tamping rod, then use a scraper to scrape the asphalt mixture along the surface of the test mold (9), and then use a preheated electric iron to iron the asphalt mixture. Step 2: quickly move the test mold (9) with the prepared sample onto the test piece installation platform (8) and start the test; turn on the vibrator (802), then use the roller steel wheel (3) to repeatedly roll the asphalt mixture 2 to 4 times, turn off the vibrator (802), then use the roller rubber wheel (4) to repeatedly roll the asphalt mixture 8 to 12 times, and then use the roller steel wheel (3) to repeatedly roll the asphalt mixture 2 to 4 times; Step 3: After the test is finished, the test mold (9) is taken out and the test piece is poured out, and the density of the compacted asphalt mixture test piece is measured by a nuclear density meter method; Step 4: Calculate the compaction degree K of the asphalt mixture specimen according to the measured density ρ1 of the compacted asphalt mixture specimen and the maximum theoretical density ρ2 of the asphalt mixture according to the following formula; K = ρ1 / ρ2 × 100%; Step 5: Repeat steps 1 to 4 until the specified compaction degree of the asphalt pavement is obtained. The loose laying coefficient S of the asphalt mixture is calculated according to the following formula based on the measured test piece height h1 compacted to the specified compaction degree and the test mold loading height h2; S=h1 / h2.

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