A concrete bridge deck-asphalt pavement base interface indentation machine and indentation parameter design method

Abstract

The application discloses a kind of concrete bridge deck-asphalt pavement base interface indentation machinery and indentation parameter design method, belong to concrete bridge deck construction machinery field, concrete bridge deck-asphalt pavement base interface indentation machinery its characterized in that, including mechanical main body, indentation roller, indentation tooth, cockpit, speed control panel, positioning antenna, steering wheel, display terminal.The indentation machinery of the application can quickly and conveniently improve the roughness of concrete base interface, and the machine can meet the demand of bridge deck large-area mechanized construction, the integrity of concrete aggregate is not damaged during construction process, and the construction efficiency is high, no dust, better construction quality, the indentation parameter design method can determine the construction timing of indentation machinery and better improve indentation tooth shape parameters, so as to better improve the interlayer bonding performance between base concrete indentation disposal interface and asphalt pavement layer.

Description

Technical Field

[0001] This invention relates to the field of concrete bridge deck construction machinery, specifically to a concrete bridge deck-asphalt pavement base layer interface indentation machine and an indentation parameter design method. Background Technology

[0002] In the construction of concrete bridge decks and asphalt pavements, to improve the bond between the concrete base layer and the asphalt pavement layer, the concrete interface needs to be roughened to remove laitance from the concrete surface, thereby improving the interlayer bond performance of the concrete bridge deck. However, traditional methods for treating the interface between the concrete bridge deck and the asphalt pavement base layer have certain drawbacks, such as:

[0003] The concrete interface roughening process, which involves creating a simple rough texture using roughening tools before the concrete initially sets, results in a low degree of roughness at the concrete interface, with a texture depth (TD) of only about 0.5 mm, which cannot meet industry requirements. The concrete interface chiseling process, which removes the surface laitance after the concrete has hardened using tools such as chisels, suffers from low construction efficiency in bridge deck paving, making it unsuitable for large-area construction of concrete bridge decks. Existing mainstream bridge deck shot blasting processes often involve significant noise pollution during interface treatment and incur material costs due to shot loss. Therefore, this invention designs a concrete bridge deck-asphalt base layer interface indentation machine and an indentation parameter design method. The indentation machine can quickly and conveniently improve the roughness of the concrete base layer interface and meets the needs of large-area mechanized bridge deck construction. It does not damage the integrity of the concrete aggregate during construction, resulting in high efficiency, no dust generation, better construction quality, and no additional material costs, thus solving the problems associated with existing concrete bridge deck-asphalt base layer interface treatment methods. Its indentation parameter design method can determine the construction timing of the indentation machine and further improve the indentation tooth parameters of the indentation machine, thereby better improving the interlayer adhesion performance between the base concrete indentation treatment interface and the asphalt pavement layer. Summary of the Invention

[0004] To address the problems existing in the traditional concrete bridge deck-asphalt base layer interface treatment methods, this invention designs a mechanical method for indentation at the concrete bridge deck-asphalt base layer interface and a method for designing indentation parameters. This is specifically achieved through the following technical solution:

[0005] A method for designing indentation parameters for the interface between concrete bridge deck and asphalt pavement base layer, wherein the indentation machine includes a main body, indentation rollers, indentation teeth, a driver's cab, a speed control plate, a positioning antenna, a steering wheel, etc.

[0006] The indentation machine uses a three-wheeled roller frame as its main body. The main body is equipped with three indentation rollers in a front-two configuration. The travel paths of the indentation rollers do not overlap, and each indentation roller has an indentation tooth layer connected to its outer edge.

[0007] The top surface of the mechanical body is fixed with a cockpit, which contains a steering wheel, speed control panel and display terminal. A positioning antenna is installed at the rear of the cockpit and is connected to the display terminal.

[0008] The indentation teeth on the indentation roller are made of materials such as steel or iron, which can withstand the weight of the indentation machinery without deformation, and do not adhere to a large amount of cement or concrete during the indentation process.

[0009] The connection between the indentation teeth and the indentation roller is achieved by welding, bonding, or other methods that ensure the indentation teeth fit tightly against the indentation roller and do not slip.

[0010] During operation, the indentation machine's display terminal in the cockpit reflects the driving speed and direction via a positioning antenna. The speed control panel and steering wheel are used to adjust the indentation machine's speed and direction. The indentation teeth on the indentation rollers are used to indent the base cement concrete surface, ensuring that the indentation machine creates uniform pit-shaped grooves on the cement concrete surface in a uniform, linear indentation manner.

[0011] The method for designing the indentation parameters of the indentation machine may include the following steps:

[0012] Step 1: Pour cement concrete into a concrete mold and allow it to set under standard curing conditions for 1 hour, 2 hours, 3 hours, and 4 hours respectively before removing it.

[0013] Step 2: Prefabricate the initial concrete interface indentation plate using 3D printing and other technologies. Indent the cement concrete at different setting times using the indentation plate. Stop and remove the indentation plate when the penetration depth reaches about 5mm.

[0014] Step 3: After the cement concrete is indented, the cement concrete specimen is demolded after curing under standard conditions for 1-2 days, and then cured for another 7 days. The laitance at the cement concrete interface after indentation is brushed off with a wire brush. The weight change of the cement concrete before and after brushing is taken as the weight of the laitance, and then the difficulty of brushing off the cement concrete laitance at different setting times is compared.

[0015] Step 4: Apply asphalt and sprinkle crushed stone on top of the indented cement concrete specimen, then add asphalt mixture to form a cement concrete + asphalt mixture composite structure specimen. Perform a 45° oblique shear test on the composite specimen to determine the interlaminar failure load F under different setting times. Combined with the cross-sectional area A of the composite specimen, calculate the interlaminar shear strength using the following formula.

[0016]

[0017] Step 5: Determine the indentation timing parameters by considering the ease of removing laitance from the cement concrete indentation interface at different setting times and the changes in interlayer shear strength.

[0018] Step 6: Keep the indentation area of ​​the indentation plate unchanged, adjust the indentation density, and when the cement concrete is cured under standard conditions to the determined indentation time, carry out concrete penetration indentation and repeat the oblique shear test. Compare the changes in interlayer shear strength under different indentation densities to determine a reasonable indentation density.

[0019] Step 7: Keep the indentation area and density of the indentation plate constant, adjust the indentation section inclination angle, and when the cement concrete is cured under standard conditions to the determined indentation time, conduct concrete penetration indentation and repeat the oblique shear test, compare the interlayer shear strength changes of different indentation section inclination angles, and determine a reasonable indentation section inclination angle.

[0020] Step 8: Keep the indentation area, density, and cross-sectional inclination angle of the indentation plate unchanged, adjust the indentation shape, and when the cement concrete is cured under standard conditions to the determined indentation time, conduct concrete penetration indentation and repeat the oblique shear test. Set up control specimens under traditional interface treatment methods such as roughening, brushing, and chiseling using steel brushes and chisels. By comparing the interlayer shear strength under different interface treatment methods, determine a more reasonable indentation shape, and use the determined indentation area, density, cross-sectional inclination angle, and shape as the shape parameters for equipping the indentation teeth of the indentation machine.

[0021] Beneficial effects:

[0022] Compared with traditional methods for treating the interface between concrete bridge decks and asphalt pavement base courses, the advantages of the mechanical indentation method and indentation parameter design method for the concrete bridge deck-asphalt pavement base course interface designed in this invention are specifically manifested in the following aspects:

[0023] 1. Using indentation machinery to complete concrete indentation work can quickly and conveniently improve the roughness of the concrete base interface, better enhance the interlayer adhesion between it and the asphalt pavement layer, and the indentation machinery can save more manpower, thereby improving construction efficiency and meeting the needs of large-area mechanized construction of bridge decks.

[0024] 2. The indentation teeth of the indentation machine can press out pit-shaped grooves during construction. Compared with traditional strip grooves, it can cope with shear stress in different directions. At the same time, the indentation machine can also control the speed and direction of the indentation operation, so that the grooves are more uniform and beautiful.

[0025] 3. The indentation parameter design method invented can determine the construction timing of the indentation machine and continuously improve the indentation tooth shape parameters of the indentation machine, thereby greatly enhancing the interlayer bonding performance of the concrete bridge deck-asphalt pavement indentation treatment interface. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the mechanical structure for indentation at the interface between the concrete bridge deck and the asphalt pavement base layer of the present invention.

[0027] Figure 2 yes Figure 1 Left view

[0028] Figure 3 This is a flowchart of the indentation parameter design method of the present invention.

[0029] Figure 4 This is a bar chart showing the weight of indentation interface laitance removed under different setting times according to the present invention.

[0030] Figure 5 This is a graph showing the variation of interlayer shear strength under the initial concrete interface indentation plate interface treatment at different setting times according to the present invention.

[0031] Figure 6 This is a schematic diagram of the shape parameters of the indentation teeth on the indentation plate of the present invention.

[0032] Figure 7 This is a bar chart of the shear strength between concrete bridge deck and asphalt pavement layers of different interface types according to the present invention.

[0033] Figure 8 This is a schematic diagram showing the shape parameters of the indentation teeth equipped with the indentation machine for the concrete bridge deck-asphalt base layer interface of the present invention.

[0034] Figure 9 This is a schematic diagram of the indentation rollers equipped with the indentation machine for the concrete bridge deck-asphalt base layer interface of the present invention.

[0035] The labels in the attached diagram have the following meanings: 1: Mechanical body; 2: Indentation roller; 3: Indentation teeth; 4: Cockpit; 5: Speed ​​control panel; 6: Positioning antenna; 7: Steering wheel; 8: Display terminal. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. However, the embodiments described are not intended to limit the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0037] A schematic diagram of the mechanical structure for indentation at the interface between concrete bridge deck and asphalt pavement base is shown below. Figure 1 As shown, it mainly includes a mechanical body, indentation rollers, indentation teeth, cockpit, speed control panel, positioning antenna, and steering wheel.

[0038] Left view of the mechanical indentation at the interface between concrete bridge deck and asphalt pavement base layer, as shown in the image. Figure 2 As shown, the indentation machine uses a three-drum roller frame as its main body. The main body is equipped with three indentation rollers in a front-two configuration. The travel paths of the indentation rollers do not overlap, and each indentation roller has an outer ring of indentation teeth.

[0039] The main body of the machine has a cockpit fixed on its top surface. The cockpit contains a steering wheel, speed control panel and display terminal. A positioning antenna is installed at the rear of the cockpit and is connected to the display terminal.

[0040] The process of designing indentation parameters for indentation machinery is as follows: Figure 3 As shown, the specific steps include the following:

[0041] Step 1: Pour the cement concrete according to the C40 cement concrete mix ratio of cement:sand:gravel:water = 398:667:1240:195 into a cylindrical cement concrete mold with a diameter of 10cm and a height of 5cm. Then place the cement concrete specimen in a constant temperature curing chamber for curing under standard conditions, and take it out after 1h, 2h, 3h and 4h respectively after the cement concrete has set.

[0042] Step 2: Use 3D printing technology to prefabricate an initial concrete interface indentation plate (right angle - 7) with a rectangular cross-section, no inclination angle, and 7 indentation teeth. Then, use a universal testing machine to indent the cement concrete with the indentation plate until the penetration depth reaches about 5mm and then remove the plate.

[0043] Step 3: After indenting the cement concrete, place the cement concrete specimen in a constant temperature curing chamber and cure under standard conditions for 1-2 days. Demold the specimen and continue curing for 7 days. Remove the specimen and use a wire brush to remove the laitance from the cement concrete interface after indentation. Figure 4 The results show that the weight of laitance removed from cement concrete at different setting times is smaller when the cement concrete has been set for 3-4 hours, and the laitance is easier to remove.

[0044] Step 4, preferably, apply 1.6 kg / m² of the cement concrete interface after indentation treatment. 2 SBS modified asphalt was spread with approximately 65% ​​coverage of 4.75-9.5mm aggregate. After the asphalt aggregate cooled completely, a 5cm high composite structural specimen of C40 cement concrete + AC-13 asphalt mixture was formed by Marshall compaction. The asphalt-aggregate ratio of the asphalt mixture was 5.0%, and the gradation design is shown in Table 1. A 45° oblique shear test with a loading rate of 10mm / min was conducted on the composite structural specimen using a universal testing machine. The interlaminar failure load F of the composite structural specimen under different setting times was determined. Combined with the cross-sectional area A of the composite specimen, the interlaminar shear strength τ was calculated using the following formula:

[0045]

[0046] Table 1. Synthetic Gradation of AC-13 Asphalt Mixture

[0047]

[0048] The interlayer shear strength variation of the initial concrete interface indentation plate (right angle - 7) interface treatment under different setting times is as follows: Figure 5 As shown, cement concrete exhibits better shear strength after approximately 3-4 hours of setting.

[0049] Step 5: Based on the ease of removing laitance from the cement concrete indentation interface at different setting times and the changes in interlayer shear strength, determine the timing of concrete indentation to be around 3-4 hours.

[0050] Step 6: Keep the indentation area of ​​the indentation plate unchanged, adjust the number of indentation teeth to four and prefabricate the indentation plate (right angle -4). Cure the cement concrete under standard conditions for about 3-4 hours, carry out cement concrete penetration indentation and repeat the oblique shear test, compare the changes in interlayer shear strength with different indentation densities, and find that the right angle -4 indentation plate has higher shear strength.

[0051] Step 7: Keeping the indentation area and density of the indentation plate unchanged, change the rectangular cross-section indentation teeth of the right-angle-4 indentation plate to trapezoidal cross-section indentation teeth with a cross-section inclination angle of 60° and prefabricate the indentation plate (trapezoidal-4). Cement concrete is cured under standard conditions for about 3-4 hours, cement concrete is penetrated into the indentation and the oblique shear test is repeated. The changes in interlayer shear strength of different indentation cross-section inclination angles are compared, and it is found that the shear strength of the trapezoidal-4 indentation plate is higher.

[0052] Step 8: Keeping the indentation area, density, and cross-sectional angle of the indentation plate constant, change the shape of the indentation teeth to circular and prefabricate the indentation plate (cone-4). Cure the cement concrete under standard conditions for approximately 3-4 hours, perform cement concrete penetration indentation, and repeat the oblique shear test. Compare the changes in interlayer shear strength. It was found that the shear strength of the trapezoidal-4 indentation plate is still higher. Combined with a steel brush and a chisel hammer, control specimens were prepared for traditional interface treatment methods such as roughening, brushing, and chiseling. Three sets of parallel specimens were taken for each interface treatment method. The diameter of the designed indentation plates of different shapes is 5 cm. The schematic diagram of the shape parameters of the indentation teeth on the indentation plate is shown below. Figure 6 As shown in the figure, the bar chart of shear strength between concrete bridge deck and asphalt pavement layers with different interface types is as follows: Figure 7 As shown.

[0053] By comparing the interlaminar shear strength under different indentation shapes and traditional interface treatments using an indentation parameter design method, the mechanically reasonable indentation parameters are derived:

[0054] (1) The timing of indentation should be selected when the cement concrete has set for about 3-4 hours under standard curing conditions.

[0055] (2) Figure 8 The diagram shows the shape parameters of the indentation teeth. The indentation shape parameters are selected as follows: the long side of the upper bottom surface is 25mm, the short side is 14mm, the cross-section is a trapezoidal indentation tooth with an inclination angle of 60°, and the height of the indentation teeth is set to 5mm.

[0056] like Figure 9 The schematic diagram of the indentation roller structure shown shows that the indentation teeth are made of steel and are welded to the indentation roller to tightly fit the indentation shape parameters mentioned above.

[0057] When cement concrete has set for about 3-4 hours under standard curing conditions, indentation work is carried out using an indentation machine. During the operation, the display terminal in the cab reflects the driving speed and direction through the positioning antenna, and the speed and direction of the indentation machine are adjusted by the speed control panel and steering wheel. The indentation teeth on the indentation rollers indent the cement concrete surface, so that the indentation machine creates uniform pit-shaped grooves on the cement concrete surface by indenting in a uniform linear manner.

[0058] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions of the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for designing indentation parameters for an indentation machine at the interface of a concrete bridge deck and asphalt pavement base, characterized in that, The indentation machine includes a mechanical body (1), indentation rollers (2), indentation teeth (3), a cab (4), a speed control plate (5), a positioning antenna (6), a steering wheel (7), and a display terminal (8). The indentation machine uses a three-wheeled roller frame as the mechanical body (1). The mechanical body (1) is equipped with three indentation rollers (2) in a front-two configuration. The travel paths of the indentation rollers (2) do not overlap. Each indentation roller (2) is connected to a layer of indentation teeth (3) around its outer edge. The top surface of the mechanical body (1) is fixed with a cab (4). The cab (4) contains a steering wheel (7), a speed control plate (5), and a display terminal (8). A positioning antenna (6) is installed at the rear of the cab (4). The positioning antenna (6) is connected to the display terminal (8). The construction timing and the shape parameters of the indentation teeth (3) of the indentation machine are determined by an indentation parameter design method. The design method includes the following steps: Step 1: Pour cement concrete into a concrete mold and allow it to set under standard curing conditions for 1 hour, 2 hours, 3 hours, and 4 hours respectively before removing it. Step 2: Precast the initial concrete interface indentation plate. Use the concrete interface indentation plate to make indentations on cement concrete at different setting times. Stop when the penetration depth reaches about 5mm and remove the indentation plate. Step 3: After the cement concrete is indented, the cement concrete specimen is demolded after curing under standard conditions for 1-2 days, and then cured for another 7 days before being taken out. The laitance at the cement concrete interface after indentation is brushed off with a wire brush, and the ease of brushing off the laitance at different setting times is compared. Step 4: Apply asphalt and sprinkle crushed stone on top of the indented cement concrete specimen, then add asphalt mixture to form a cement concrete + asphalt mixture composite structure specimen. Perform a 45° oblique shear test on the composite specimen to determine the interlaminar failure load F of the composite structure specimen under different setting times. Combined with the cross-sectional area A of the composite specimen, the interlaminar shear strength τ is obtained by the following formula: Step 5: Determine the indentation timing parameters by considering the ease of removing laitance from the cement concrete indentation interface and the changes in interlayer shear strength under different setting times. Step 6: Keep the indentation area of ​​the indentation plate unchanged, adjust the indentation density, and when the cement concrete is cured under standard conditions to the determined indentation time, carry out concrete penetration indentation and repeat the oblique shear test. Compare the changes in interlayer shear strength under different indentation densities to determine a reasonable indentation density. Step 7: Keep the indentation area and density of the indentation plate unchanged, and then adjust the indentation section inclination angle. When the cement concrete is cured under standard conditions to the determined indentation time, the concrete penetrates the indentation and the oblique shear test is repeated. The interlayer shear strength changes of different indentation section inclination angles are compared to determine a reasonable indentation section inclination angle. Step 8: Keep the indentation area, density and cross-sectional inclination angle of the indentation plate unchanged, and then change the indentation shape. When the cement concrete is cured under standard conditions to the determined indentation time, concrete penetration indentation is carried out and oblique shear test is repeated. The control specimens under roughening, brushing and chiseling are set by steel brush and chisel hammer. By comparing the interlayer shear strength under different interface treatment methods, a more reasonable indentation shape is determined. The determined indentation area, density, cross-sectional inclination angle and shape are used as the shape parameters of the indentation teeth (3) of the indentation machine.

2. The indentation parameter design method according to claim 1, characterized in that... The indentation teeth (3) on the indentation roller (2) are made of steel or iron material that can withstand the weight of the indentation machine without deformation, and will not adhere to a lot of cement concrete during the indentation process.

3. The indentation parameter design method according to claim 1, characterized in that... The indentation teeth (3) and the indentation roller (2) are connected by welding or bonding to ensure that the indentation teeth (3) fit tightly against the indentation roller (2) and do not slip.

4. The indentation parameter design method according to claim 1, characterized in that... During the operation of the indentation machine, the display terminal (8) in the cockpit (4) reflects the driving speed and direction through the positioning antenna (6), and adjusts the driving speed and direction of the indentation machine through the speed control board (5) and the steering wheel (7). The indentation teeth (3) on the indentation roller (2) are used to indent the surface of the base cement concrete, ensuring that the indentation machine produces uniform pit-shaped grooves on the cement concrete surface in a uniform linear indentation manner.

5. The indentation parameter design method according to claim 1, characterized in that... In step 2, the prefabrication of the indentation plate is carried out using 3D printing technology to precisely prefabricate the indentation plate with specific shape parameters.

6. The indentation parameter design method according to claim 1, characterized in that... The difficulty of removing the cement concrete laitance in step 3 is evaluated by the difference in weight of the cement concrete before and after removal, i.e., the weight of the laitance.

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