Asphalt concrete longitudinal and transverse joint treatment method

Abstract

The invention belongs to the technical field of asphalt concrete base construction, and particularly relates to an asphalt concrete longitudinal and transverse joint treatment method. The method comprises a bituminous concrete longitudinal joint treatment step and a bituminous concrete transverse joint treatment step. The longitudinal joint treatment step comprises formwork erecting; longitudinal templates are laid on the edge of the paving surface and fixed; the concrete materials on the inner sides of the longitudinal formworks are spread and rolled; the longitudinal formworks are removed after cooling, and paving of longitudinal adjacent sections is started; after paving is completed, longitudinal joint static pressure and paving surface rolling are carried out; the transverse joint treatment step comprises the steps of pre-burying a transverse template and then starting longitudinal rolling; after rolling is completed, mold removal is started after the asphalt concrete surface is cooled and shaped, and then transverse joints are paved, rolled and trimmed; and after the transverse joints are treated, the longitudinal rolling process is started. The longitudinal formworks and the transverse formworks can provide effective support in the asphalt concrete compaction process, mixed materials are prevented from overflowing, and the compaction degree and porosity of the edge asphalt concrete are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of asphalt concrete base construction, and in particular relates to a method for processing longitudinal and transverse joints of asphalt concrete. Background Art

[0002] Asphalt concrete is a mixture of carefully selected mineral materials, crushed stone or crushed gravel, stone chips or sand, mineral powder, etc., mixed with road asphalt materials in a specific proportion under strictly controlled conditions. As a key pavement material, asphalt concrete plays an irreplaceable role in ensuring traffic safety, improving pavement durability, and reducing maintenance costs. With the rapid advancement of urbanization in China and the continuous growth of transportation demand, the demand for asphalt concrete is also continuing to rise.

[0003] However, due to the large width and length of the construction surface of highways, airport runways, taxiways, large parking lots, etc., and the relatively small operating range and limited daily output of asphalt pavers, paving operations must be carried out in multiple times. This inevitably requires the new pavement to be spliced ​​with the previously compacted pavement. If the joints are directly spliced ​​without proper treatment, the pavement at the joint will be uneven and may even cause damage to the structural layer. This is because the first pavement is not restrained laterally during rolling, and the edge part cannot be compacted; and when the second pavement is paved, the asphalt concrete has cooled and can no longer be effectively rolled, resulting in insufficient and uneven strength of the asphalt concrete base at the joint. When large vehicles pass by, it will cause a large impact on the pavement structure, causing uneven depressions or even damage to the pavement. Therefore, choosing the right cold joint treatment technology is crucial to preventing these problems and improving the overall construction quality of the project.

[0004] At present, the conventional joint treatment method is to use a 3-meter ruler to determine the location of the thickness change of the cross section in the paved layer, and use a cutting machine to vertically cut off the asphalt concrete surface that does not meet the specification requirements. However, this method has several problems:

[0005] 1. It will lead to a lot of waste of asphalt concrete, thus increasing costs;

[0006] 2. The cutting process is difficult, and it is difficult to ensure the flatness and straightness of the cut surface. The dust generated is not easy to clean after contact with water, which affects the quality of the project;

[0007] 3. There are certain safety hazards in cutting operations; the cutting process will also cause damage to cutting equipment and related accessories. Summary of the invention

[0008] In response to the problems existing in the prior art, the present invention provides a method for processing the longitudinal and transverse joints of asphalt concrete. Reinforced concrete columns and steel chisels are used as templates. Effective support can be provided during the compaction of asphalt concrete to prevent the mixture from overflowing. The construction technology is advanced and the problems of unqualified compaction and porosity of edge asphalt concrete are solved.

[0009] The present invention is achieved in that:

[0010] A method for processing longitudinal and transverse joints of asphalt concrete, the method comprising a step of processing longitudinal joints of asphalt concrete and a step of processing transverse joints of asphalt concrete;

[0011] a. The longitudinal seam processing step comprises:

[0012] a1. Set up the mold;

[0013] Lay out a certain distance along the edge of the paving surface, lay out the longitudinal formwork one by one and fix it at the designated position at the edge;

[0014] a2. Paving and compaction;

[0015] After laying the longitudinal formwork, clean the bottom layer and the surface, re-measure the level points and the center line of the entire line; then unload the concrete material to the inside of the formwork for paving; roll the concrete virtual paving layer that is higher than the horizontal formwork until its height is flush with the top of the formwork to obtain the preliminary paving surface;

[0016] a3, unloading the mold and width;

[0017] After the compacted asphalt concrete has completely cooled, remove all longitudinal formwork in that section and prepare to start paving the adjacent longitudinal sections;

[0018] Before paving, clean the longitudinal joints of the previous paving surface and apply asphalt bonding oil;

[0019] Start longitudinal joint paving according to steps a1 and a2. At this time, the hot material at the longitudinal joint needs to be leveled and trimmed to control the virtual paving layer of the new paving surface and prevent the hot material from being paved to the previous paving surface;

[0020] After paving is completed, a steel wheel roller is used to perform static compression of the longitudinal seams. The main body of the vehicle is on the previously paved surface. The steel wheel is extended into the new paved surface for about 20 to 30 cm to perform the initial compression of the hot material, and then static compression is performed from one side to the inside. After the static compression is completed, the paved surface is rolled;

[0021] b. Horizontal seam processing steps:

[0022] b1. Pre-embedded horizontal formwork;

[0023] Use a ruler to check the flatness of the horizontal paving surface, and use the gap between the asphalt concrete surface layer and the ruler as the dividing line. Draw a straight line on this dividing line and bury the horizontal formwork; then make a slope treatment on the excess hot material on the back of the formwork to form an asphalt concrete slope surface;

[0024] b2. Compacting;

[0025] Start the longitudinal rolling process according to step a2; to ensure the compaction of the joint, the roller must completely roll over the slope behind the template before stopping;

[0026] b3, unloading the mold and width;

[0027] After the rolling is completed, wait until the asphalt concrete surface is completely cooled and shaped before removing the mold, then trim the transverse joints and apply asphalt bonding oil; then spread, roll and trim the transverse joints; after the transverse joints are processed, start the normal longitudinal rolling process according to step a2.

[0028] Furthermore, the longitudinal formwork and the transverse formwork are both rectangular reinforced concrete columns; a plurality of transparent prefabricated holes are evenly arranged on the reinforced concrete column along its length direction, and steel chisels are arranged in the prefabricated holes; the top of the steel chisel is flush with the top of the concrete column to facilitate subsequent steel wheel rolling, and the sharp bottom of the steel chisel extends downward to the outside of the reinforced concrete column, so as to facilitate insertion into a fixed position.

[0029] Furthermore, in step a2, the compaction direction is parallel to the center line of the road, and static compaction is performed first, followed by vibration, and finally static compaction. The compaction density is required to be 98% of the Marshall density of asphalt concrete.

[0030] Furthermore, in step a2, the rolling of asphalt concrete includes three steps: initial rolling, repeated rolling and final rolling. The rolling order of each step is from edge to center and from lowest to highest.

[0031] Furthermore, in step a2,

[0032] 4) Initial compaction involves rolling slowly from the outside to the center with a double-wheel roller, ensuring that adjacent rolled strips overlap by 1 / 3 to 1 / 2 wheel width;

[0033] 5) Use a vibratory roller for recompacting. The number of times of rolling is determined according to the test, usually not less than 4 to 6 times. The recompacting is carried out immediately after the initial rolling. The rolling temperature shall not be lower than 120℃ and the speed shall be controlled within the specified range.

[0034] 6) In the final compaction stage, use a steel-wheel roller with a rubber wheel to knead the dough. Subsequently, use a double-wheel steel drum roller or a vibratory roller with vibration turned off to perform static compaction at least twice. The compaction temperature should be maintained above 100°C.

[0035] Furthermore, in step b3, the formwork is removed before paving, the horizontal formwork is removed, the horizontal joints are trimmed, and asphalt bonding oil is applied before continuing the longitudinal paving.

[0036] Furthermore, in step b3, the loose paving coefficient of AC type asphalt mixture is between 1.2 and 1.25.

[0037] The advantages and technical effects of the present invention are as follows:

[0038] The invention discloses a technology for processing longitudinal and transverse joints of asphalt concrete, which involves setting prefabricated reinforced concrete columns as templates at the edges of the paving width before paving the asphalt concrete. The templates are reinforced by steel chisels to ensure that the edge materials obtain necessary lateral constraints during the compaction of the asphalt concrete.

[0039] For the treatment of longitudinal joints and transverse joints, the present invention adopts the vertical formwork method and the embedded formwork method respectively to lay reinforced concrete columns and implement different widening strategies to meet the needs of joint treatment in different directions.

[0040] Compared with the prior art, the advantages of the present invention are:

[0041] (1) It avoids cutting the asphalt concrete at the edge, thus saving a large amount of asphalt concrete raw materials and effectively reducing material costs;

[0042] (2) The device of the present invention has a simple structure and is easy to operate. Only a small amount of manpower is required to complete installation and disassembly, which significantly improves construction efficiency;

[0043] (3) Reinforced concrete columns and steel chisels are used as formwork to provide effective support during the compaction of asphalt concrete and prevent the mixture from overflowing. The innovative nature of this construction technology solves the problem of substandard compaction and porosity of edge asphalt concrete, significantly improving the acceptance rate of the project. The resulting asphalt concrete surface at the joints is regular, dense, flat, and beautiful, significantly improving the overall project quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is an overall schematic diagram of a reinforced concrete column of the present invention;

[0045] Figure 2 for Figure 1 A front view of

[0046] Figure 3 for Figure 1 Side view of

[0047] Figure 4 for Figure 1 A top view of

[0048] Figure 5 A mold drawing for processing the longitudinal seam of the present invention;

[0049] Figure 6 It is the longitudinal seam width diagram of the present invention;

[0050] Figure 7 This is a transverse joint pre-embedded template diagram of the present invention;

[0051] Figure 8 This is the width diagram of the transverse seam of the present invention.

[0052] In the figure: 1. Reinforced concrete column; 2. Steel chisel; 3. False paving layer of previous paving; 4. Previous paving; 5. Asphalt bonding oil; 6. False paving layer of new paving; 7. New paving; 8. Steel wheel roller; 9. Asphalt concrete slope surface; 10. Stone powder; 11. Small double steel wheel roller. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0054] like Figures 1 to 8 As shown, the present invention discloses a method for processing longitudinal and transverse joints of asphalt concrete, which includes a step for processing longitudinal joints and a step for processing transverse joints of asphalt concrete;

[0055] a. The longitudinal seam processing step comprises:

[0056] a1. Set up the mold;

[0057] like Figure 5 As shown, a certain distance is laid out on the edge of the paving surface, and longitudinal formwork is laid one by one and fixed at the designated position on the edge;

[0058] The template is a plurality of rectangular reinforced concrete columns 1 of the same size, on which a plurality of transparent prefabricated holes are evenly arranged along the length direction, and steel chisels are arranged in the prefabricated holes; the top of the steel chisel is flush with the top of the concrete column to facilitate subsequent steel wheel rolling, and the sharp bottom of the steel chisel extends downward to the outside of the reinforced concrete column, so as to facilitate insertion into a fixed position.

[0059] The concrete columns must be in close contact with each other to prevent asphalt concrete from overflowing from the edge gaps; before laying the concrete columns, clean the road surface under the concrete columns and remove the gravel or other aggregates on the road surface to make the contact between the concrete columns and the road surface closer, reduce sliding, and improve the smoothness and straightness of the edges.

[0060] In this step, reinforced concrete columns 1 are laid one by one along the laying-out direction as templates, which can provide effective support during the compaction of asphalt concrete and prevent the mixture from overflowing.

[0061] a2. Paving and compaction;

[0062] After laying the longitudinal formwork, first clean the bottom layer with a broom or air compressor to keep the surface clean, and re-measure the leveling points and center lines of the entire line. After the mixture is transported to the site, it is slowly unloaded into the hopper by a dump truck, and then the asphalt concrete is spread according to the conventional method. At this moment, there is a virtual paving layer 3 of the previous paving on the top of the asphalt concrete on the inner side of the concrete column, so it needs to be compacted until its height is flush with the concrete column baffle to obtain the previous paving 4. The normal process of rolling asphalt concrete is divided into three steps: initial compaction, re-compacting and final compaction to meet the compaction and flatness requirements. The loose paving thickness and the paving elevation angle of the paver must be tested in the test section and adjusted in real time during the paving process. The loose paving coefficient is mainly affected by two aspects. On the one hand, it is the gradation of the mixture, and on the other hand, it is the initial density of the paver. The loose paving coefficient is not fixed for different materials, different paving machinery or different construction methods. However, the loose paving coefficient will generally have a range of variation. For example: the loose paving coefficient of AC asphalt mixture is between 1.2 and 1.25;

[0063] The following requirements shall be met during rolling:

[0064] 7) Roller rolling sequence: The rolling sequence is from edge to center, from lowest to highest, with tracks overlapping by 20 cm. When rolling the edge, the steel wheel must fully press the template until the required density, flatness and level requirements are met;

[0065] 8) Initial compaction involves slowly rolling with a double-wheel roller from the outside to the center, ensuring that adjacent rolling strips overlap by 1 / 3 to 1 / 2 wheel width. This step is intended to initially stabilize and level the asphalt mixture, laying the foundation for subsequent re-compacting.

[0066] 9) Use a vibratory roller for recompacting. The number of times of rolling is determined according to the test, usually not less than 4 to 6 times. The recompacting must ensure that the specified compaction degree is achieved and the mixture is dense and stable. The recompacting is carried out immediately after the initial rolling. The rolling temperature must not be lower than 120℃ and the speed must be controlled within the specified range.

[0067] 10) In the final compaction stage, a steel-wheeled rubber-wheeled roller is used to knead the surface to press the surface aggregate into the interior and reduce the pattern and gaps. Subsequently, a double-wheeled steel drum type or a vibrating roller with vibration turned off is used for static compaction at least twice at a slow speed. The final compaction aims to eliminate wheel marks and ensure a smooth road surface. The compaction temperature should be kept above 100°C.

[0068] 5) The initial, repeated and final compaction sections should be clearly marked to facilitate identification by drivers. Special posts should be set up to manage and inspect the loose paving thickness, compaction sequence, roller combination, compaction times, compaction speed and compaction temperature to resolutely prevent surface layer compaction leakage;

[0069] 6) The number of rolling times is determined based on the compaction and flatness measured after compaction; compaction requirements: the compaction density requirement is 98% of the Marshall density of asphalt concrete;

[0070] 7) During the rolling process, water should be sprayed in appropriate amounts, and the high temperature should be maintained while compacting in sections, and the same section should be compacted repeatedly;

[0071] 8) Compaction direction: parallel to the center line of the road.

[0072] a3. Unloading and Width Assembly

[0073] like Figure 6 As shown, after the compacted asphalt concrete is completely cooled, all concrete columns and steel bars of the section are removed, and the paving of the longitudinally adjacent sections begins; however, the longitudinal joints of the previous section must be cleaned in advance to make the cut surface neat and clean, and asphalt bonding oil 5 must be applied to enhance the bonding force and prevent moisture penetration.

[0074] When starting to pave the longitudinal joints, arrange a special person to level and trim the hot material at the longitudinal joints. The main purpose is to control the virtual paving layer 6 of the new paving surface and prevent the hot material from being spread to the previous paving surface 4;

[0075] After paving is completed, a steel wheel roller 8 is used for longitudinal rolling. During rolling, the main body of the vehicle should be on the previous paved surface 4. The steel wheel extends into the new paved surface 7 for about 20 to 30 cm to perform initial pressing of the hot material, and then static pressing is performed from one side to the inside.

[0076] After the static pressure of the longitudinal seam is completed, the contact surface of the gap is measured to check whether the gap is fully filled with hot material, whether there is overflow or lack of material on the gap section, and it is manually leveled and repaired to make it fully connected with the joint surface. After the joint treatment is completed, the normal rolling process begins. The specific rolling process is described in step a2.

[0077] b. Horizontal seam processing steps:

[0078] b1. Embedded horizontal formwork

[0079] like Figure 7As shown, the transverse joint treatment is to pre-embed the transverse templates one by one along the transverse direction of the paving surface, and the transverse templates are also reinforced concrete columns 1. After the longitudinal paving work is completed, the paver is lifted off, and then the flatness of the transverse paving surface is tested with a 3-meter ruler. The gap between the asphalt concrete surface layer and the ruler is used as the dividing line. The line is drawn straight on this dividing line, and the template, i.e., the reinforced concrete column 1, is buried and fixed with a steel chisel 2 through the prefabricated hole. The steel chisel 2 needs to be fully inserted into the concrete column to ensure the smooth operation of the steel wheel roller 8. Then, the excess hot material on the back of the concrete column is sloped to form an asphalt concrete slope surface 9. Stone powder 10 is laid on the bottom surface outside the template in advance to prepare for the removal of the asphalt concrete slope surface 9.

[0080] b2. Compaction

[0081] Start the normal longitudinal rolling process. The specific rolling process is as described in step a2. To ensure the compaction of the joint, the roller must completely pass the slope behind the template before stopping.

[0082] b3. Unloading and Width Assembly

[0083] like Figure 8 As shown, after the rolling is completed, wait until the asphalt concrete surface is completely cooled and shaped before starting to demould, remove the transverse template, then trim the transverse joints and apply asphalt bonding oil 5; when starting to pave the transverse joints, it is very important to start the paver, and the paving elevation angle and paving thickness must be adjusted before starting paving; arrange special personnel to check the virtual paving and flatness of the transverse joints.

[0084] When rolling the transverse joint, first use a small double-steel wheel roller 11 to initially roll the joint horizontally. The rolling width should not be too wide, and each time it should be 20 to 30 cm, and then push inwards to prevent the asphalt concrete material from shifting and causing the joint to be low. After the initial rolling is completed, use a ruler to check the flatness of the joint. If it is not flat, it needs to be manually leveled and repaired to make it fully connected with the joint surface. After the joint is processed, the normal longitudinal rolling process begins. The specific rolling process is as described in step a2.

[0085] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for treating longitudinal and transverse joints of asphalt concrete, characterized in that: The method comprises a step of processing a longitudinal joint of asphalt concrete and a step of processing a transverse joint; a. The longitudinal seam processing step comprises: a1. Set up the mold; Lay out a certain distance along the edge of the paving surface, lay out the longitudinal formwork one by one and fix it at the designated position at the edge; a2. Paving and compaction; After laying the longitudinal formwork, clean the bottom layer and the surface, re-measure the level points and the center line of the entire line; then unload the concrete material to the inside of the formwork for paving; roll the concrete virtual paving layer that is higher than the transverse formwork several times until its height is flush with the top of the formwork to obtain the preliminary paving surface; a3, unloading the mold and width; After the compacted asphalt concrete has completely cooled, remove all longitudinal formwork in that section and prepare to start paving the adjacent longitudinal sections; Before paving, clean the longitudinal joints of the previous paving surface and apply asphalt bonding oil; Start longitudinal joint paving according to steps a1 and a2. At this time, the hot material at the longitudinal joint needs to be leveled and trimmed to control the virtual paving layer of the new paving surface and prevent the hot material from being paved to the previous paving surface; After paving is completed, a steel wheel roller is used to perform static compression of the longitudinal seams. The main body of the vehicle is on the previously paved surface. The steel wheel is extended into the new paved surface for about 20 to 30 cm to perform the initial compression of the hot material, and then static compression is performed from one side to the inside. After the static compression is completed, the paved surface is rolled; b. Horizontal seam processing steps: b1. Pre-embedded horizontal formwork; Use a ruler to check the flatness of the horizontal paving surface, and use the gap between the asphalt concrete surface layer and the ruler as the dividing line. Draw a straight line on this dividing line and bury the horizontal formwork; then make a slope treatment on the excess hot material on the back of the formwork to form an asphalt concrete slope surface; b2. Compacting; Start the longitudinal rolling process according to step a2; to ensure the compaction of the joint, the roller must completely roll over the slope behind the template before stopping; b3, unloading the mold and width; After the rolling is completed, wait until the asphalt concrete surface is completely cooled and shaped before removing the mold, then trim the transverse joints and apply asphalt bonding oil; then spread, roll and trim the transverse joints; after the transverse joints are processed, start the normal longitudinal rolling process according to step a2.

2. The method for treating longitudinal and transverse joints of asphalt concrete according to claim 1, characterized in that: The longitudinal formwork and the transverse formwork are both rectangular reinforced concrete columns; a plurality of transparent prefabricated holes are evenly arranged on the reinforced concrete column along its length direction, and steel chisels are arranged in the prefabricated holes; the top of the steel chisel is flush with the top of the concrete column to facilitate subsequent steel wheel rolling, and the sharp bottom of the steel chisel extends downward to the outside of the reinforced concrete column, so as to facilitate insertion into a fixed position.

3. The method for treating longitudinal and transverse joints of asphalt concrete according to claim 1, characterized in that: In step a2, the compaction direction is parallel to the center line of the road, and static pressure is performed first, then vibration, and finally static pressure. The compaction density is required to be 98% of the Marshall density of asphalt concrete.

4. The method for treating longitudinal and transverse joints of asphalt concrete according to claim 1, characterized in that: In step a2, the rolling of asphalt concrete includes three steps: initial rolling, repeated rolling and final rolling. The rolling order of each step is from edge to center and from lowest to highest.

5. The method for treating longitudinal and transverse joints of asphalt concrete according to claim 4, characterized in that: In step a2, 1) Initial compaction involves rolling slowly from the outside to the center with a double-wheel roller, ensuring that adjacent rolled strips overlap by 1 / 3 to 1 / 2 wheel width; 2) Use a vibratory roller for recompacting. The number of times of rolling is determined according to the test, usually not less than 4 to 6 times. The recompacting is carried out immediately after the initial rolling. The rolling temperature shall not be lower than 120℃ and the speed shall be controlled within the specified range. 3) In the final compaction stage, use a steel wheel roller with a rubber wheel to knead the dough. Subsequently, use a double-wheel steel drum roller or a vibratory roller with vibration turned off to perform static compaction at least twice. The compaction temperature should be maintained above 100°C.

6. The method for treating longitudinal and transverse joints of asphalt concrete according to claim 1, characterized in that: In step b3, the formwork is removed before paving, the horizontal formwork is removed, the horizontal joints are trimmed, and after applying asphalt bonding oil, longitudinal paving is continued.

7. The method for treating longitudinal and transverse joints of asphalt concrete according to claim 1, characterized in that: In step b3, the loose paving coefficient of AC asphalt mixture is between 1.2 and 1.25.

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