A large-diameter hydraulic asphalt concrete paving method

Abstract

The present application relates to the technical field of roller compacted asphalt concrete impervious core wall in water conservancy and hydropower engineering, and particularly relates to a large-particle-size hydraulic asphalt concrete paving method, comprising the following steps: A. preparing the asphalt concrete core wall construction warehouse surface before paving; B. paving the large-particle-size hydraulic asphalt mixture prepared according to the optimized mixing ratio by using special paving equipment; C. compacting the large-particle-size hydraulic asphalt mixture to form a large-particle-size hydraulic asphalt concrete layer. The present application effectively solves the quality hidden trouble caused by paving the large-particle-size hydraulic asphalt concrete by using the existing hydraulic asphalt concrete paving technology, and highlights the advantages of fast construction speed, effective reduction of construction period and cost reduction of the large-particle-size hydraulic asphalt concrete.

Description

Technical Field

[0001] This invention belongs to the technical field of roller-compacted asphalt concrete anti-seepage core wall in water conservancy and hydropower engineering, and specifically relates to a method for paving large-particle-size hydraulic asphalt concrete. Background Technology

[0002] Asphalt concrete core walls in hydraulic engineering can adapt to various complex climatic conditions and have good seepage prevention and seismic resistance. Asphalt concrete core wall seepage prevention technology is widely used in the upper and lower reservoir dams of pumped storage power stations.

[0003] Large-particle-size hydraulic asphalt concrete is made by compacting hot-mix asphalt mixtures containing aggregates with a maximum particle size between 26.5 and 31.5 mm. Large-particle-size hydraulic asphalt concrete has the following three advantages: ① Well-graded large-particle-size asphalt concrete can resist greater plasticity and shear deformation, withstand high water heads, and is suitable for constructing high dams; ② The specific surface area of ​​the aggregates in large-particle-size hydraulic asphalt concrete is relatively smaller, resulting in less asphalt usage and thus lower project costs; ③ Large-particle-size hydraulic asphalt concrete has a relatively larger paving thickness, allowing for faster construction and reducing construction time and costs.

[0004] The key process for constructing a roller-compacted asphalt concrete core wall is as follows: the asphalt mixture is laid by a paver and compacted by a vibratory roller. Using existing traditional hydraulic asphalt concrete paving technology for large-particle-size hydraulic asphalt concrete presents the following quality risks: With the increase in maximum aggregate size and paving thickness, using existing self-falling discharge pavers with formwork self-weight extrusion molding for large-particle-size hydraulic asphalt mixtures easily leads to coarse aggregate segregation, causing uneven asphalt mixture quality. Furthermore, to achieve the formwork self-weight extrusion molding effect, the paver's travel speed must be reduced, diminishing the advantage of faster construction speeds due to the large paving thickness. Using the current DL / T5363-2016 "Specification for Construction of Roller-Compacted Asphalt Concrete" 7.5.1 with a dedicated vibratory roller of less than 1.5t for compaction, the impact force generated is insufficient to be transmitted to the pre-paved layer, making it difficult for the coarse aggregate of the newly paved asphalt mixture to embed into the pre-paved layer. Moreover, using only a double-steel-drum vibratory roller makes it difficult for "oil seepage" to occur on the paved layer, affecting interlayer bonding quality and easily forming seepage channels. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, this invention provides a method for paving large-particle-size hydraulic asphalt concrete. This method solves the quality risks caused by paving large-particle-size hydraulic asphalt concrete using existing hydraulic asphalt concrete paving techniques. Compared with traditional hydraulic asphalt concrete, large-particle-size hydraulic asphalt concrete exhibits advantages such as strong deformation resistance, fast construction speed, effectively shortened construction period, and reduced costs.

[0006] To achieve the above objectives, the present invention provides a method for paving large-particle-size hydraulic asphalt concrete, comprising the following steps:

[0007] A. Preparatory work before paving the asphalt concrete core wall construction site includes: detection and treatment of the non-nuclear density meter in the construction defect area, treatment of the contaminated area of ​​the site, and detection of the site temperature;

[0008] B. Use specialized paving equipment to pave large-particle-size hydraulic asphalt mixtures prepared according to the optimized mix proportions;

[0009] The paving of the large-particle-size hydraulic asphalt mixture using the special paving equipment includes: power extruding the large-particle-size hydraulic asphalt mixture into strips, the width of which is the thickness of the core wall of the construction layer, and the height of which is 35-40cm; laying 50-type diamond mesh on both sides of the power-extruded asphalt mixture strips and continuously paving them on the asphalt concrete surface.

[0010] C. Compact the paved large-particle-size hydraulic asphalt mixture to form a large-particle-size hydraulic asphalt concrete layer.

[0011] The compaction of the large-particle-size hydraulic asphalt mixture after paving includes: first, compacting the transition material on both the upstream and downstream sides of the core wall in parallel, and then compacting the paved large-particle-size hydraulic asphalt mixture.

[0012] When the transition material on both sides of the parallel compaction core wall is being compacted, the remaining transition material with a width of 30-50cm from both sides of the core wall is not compacted, and then compacted together with the large-particle-size hydraulic asphalt mixture.

[0013] The compaction of the large-particle-size hydraulic asphalt mixture after paving includes: initial rolling with static compaction by a double-drum vibratory roller; secondary rolling with a combination of vibration compaction by a double-drum vibratory roller and compaction by a heavy-duty rubber-tired roller; and final rolling with static compaction by a double-drum roller.

[0014] The double steel wheel vibratory roller used for the initial, secondary, and final rolling of large-particle-size hydraulic asphalt mixtures is a dedicated vibratory roller with a capacity of not less than 3 tons.

[0015] The beneficial effects of this invention are as follows:

[0016] This invention effectively solves the quality problems that are prone to occur when paving large-particle-size hydraulic asphalt concrete using existing paving techniques, ensures the construction quality of large-particle-size hydraulic asphalt concrete core walls, improves the construction speed of roller-compacted asphalt concrete core walls, shortens the construction period, and reduces the construction cost of asphalt concrete core wall projects. The method of using dynamic extrusion molding of large-diameter hydraulic asphalt mixture in a paver effectively solves the problem of slowing down the paver's travel speed and reducing the construction speed caused by the increased paving thickness of large-diameter hydraulic asphalt concrete in existing paving technologies to achieve the extrusion molding effect of the paver template. The application of 50-type diamond mesh on both sides of the dynamic extrusion molding strip of large-diameter hydraulic asphalt mixture effectively solves the problem of coarse aggregate segregation and uneven asphalt mixture quality caused by using existing pavers with self-fall discharge and template self-weight extrusion molding when paving large-diameter hydraulic asphalt mixture with the increase of maximum aggregate size and paving thickness. The use of a combination of vibratory rolling with a special double steel wheel roller of no less than 3t followed by heavy rubber-tired roller effectively solves the problem of interlayer bonding quality in the construction of large-diameter hydraulic asphalt concrete core wall. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the asphalt mixture travel path of the power extrusion molding paver of the present invention.

[0018] Figure 2 This is a schematic diagram of the asphalt mixture travel path of a dedicated paver for self-weight extrusion molding of existing templates.

[0019] Figure 3 It is a triaxial test specimen cut from a core sample of large-particle-size hydraulic asphalt concrete with a maximum aggregate size of 26.5 mm in the preferred mix proportion.

[0020] Figure 4 The specimens are triaxial test specimens cut from core samples of large-particle-size hydraulic asphalt concrete with a maximum aggregate size of 31.5 mm in the preferred mix proportion.

[0021] In the diagram: 1-Asphalt mixture hopper for a dedicated paver; 2-Power extrusion molding chamber; 3-Church; 4-Asphalt concrete slab surface; 5-Power-extruded strip-shaped asphalt mixture; 6-Asphalt mixture falling freely; 7-Paver template. Detailed Implementation

[0022] The following describes the specific implementation process of this application and its appendices. Figure 3 , 4 The technical solution of this application is described in detail.

[0023] Example 1

[0024] A method for paving large-particle-size hydraulic asphalt concrete includes the following steps:

[0025] A. Preparatory work before paving the asphalt concrete core wall construction site includes: non-nuclear density meter testing and treatment of construction defect areas, treatment of contaminated areas on the site surface, and temperature testing of the site surface.

[0026] B. For large-particle-size hydraulic asphalt mixtures prepared according to the optimized mix proportions, specialized paving equipment should be used for paving.

[0027] The large-particle-size hydraulic asphalt mixture special paving equipment is used for paving such as Figure 1 As shown: Large-diameter hydraulic asphalt mixture from hopper 1 is conveyed into the power extrusion chamber 2, where it is power-extruded into strips. The width of these strips is equal to the thickness of the core wall of the construction layer, and the height is 35-40 cm. 50-type diamond mesh is then laid on both sides of the extruded asphalt mixture strips via chute 3, and the mixture is continuously spread onto the asphalt concrete surface 4. Current dedicated hydraulic asphalt mixture paving equipment is used for paving as follows: Figure 2 As shown: The asphalt mixture in hopper 1 is conveyed and falls freely into the asphalt concrete slab surface 4, and then the paver template 7 is used to compress it into a strip shape by its own weight and continuously spread it on the asphalt concrete slab surface 4; the large-particle-size hydraulic asphalt mixture is spread using the current special paving equipment for hydraulic asphalt mixture. When it falls freely into the asphalt concrete slab surface 4, coarse aggregate segregation is likely to occur, resulting in uneven quality problems of the large-particle-size hydraulic asphalt mixture.

[0028] C. The large-particle-size hydraulic asphalt mixture after paving is compacted to form a large-particle-size hydraulic asphalt concrete layer.

[0029] The compaction of the large-particle-size hydraulic asphalt mixture after paving includes: first, compacting the transition material on both the upstream and downstream sides of the core wall in parallel, and then compacting the large-particle-size hydraulic asphalt mixture after paving.

[0030] When the transition material on both sides of the parallel compaction core wall is being compacted, a 30-50cm wide gap between the upper and lower sides of the core wall is left uncompacted and then compacted together with the large-particle-size hydraulic asphalt mixture.

[0031] The compaction of the large-diameter hydraulic asphalt mixture after paving includes: initial rolling with static rolling by a double-drum roller; secondary rolling with a combination of vibratory rolling by a double-drum roller and subsequent rolling by a heavy-duty rubber-tired roller; and final rolling with static rolling by a double-drum roller.

[0032] The double steel wheel vibratory roller used for the initial, secondary, and final rolling of large-particle-size hydraulic asphalt mixtures is a dedicated vibratory roller with a capacity of not less than 3 tons.

[0033] The maximum aggregate particle size range of the large-particle-size hydraulic asphalt concrete is 26.5–31.5 mm.

[0034] The paving thickness of the large-particle-size hydraulic asphalt mixture is 35-40cm.

[0035] Example 2

[0036] A method for paving large-particle-size hydraulic asphalt concrete with a preferred mix proportion of 26.5 mm as the maximum aggregate size includes the following steps:

[0037] A. Prepare the construction surface of the asphalt concrete core wall before paving; conduct an overall inspection of the construction surface of the asphalt concrete core wall, and for areas with construction defects—such as honeycomb pitting: first, use a nucleus-free density meter to test the density and obtain the porosity of the area. If the porosity is ≤3%, fill the honeycomb pit with hot asphalt; if the porosity is >3%, drill a core sample, and test the core sample porosity in the laboratory. If the core sample porosity is ≤3%, fill the honeycomb pit with hot asphalt; if the porosity is >3%, remove the area and repave with asphalt concrete. Contamination of the construction surface is mainly caused by dust from dam construction or rainwater. Dust can be blown away with an air compressor; rainwater should be washed clean with water and dried. Use an insertion digital thermometer to check the surface temperature of the slab. If the surface temperature is less than 70°C, the slab must be heated before paving. If the surface temperature is between 70-90°C, paving can be done directly. If the surface temperature is greater than 90°C, the surface must be cooled to below 90°C before paving.

[0038] B. Specialized paving equipment should be used to pave large-particle-size hydraulic asphalt mixtures prepared according to the optimized mix proportions.

[0039] The large-particle-size hydraulic asphalt mixture special paving equipment is used for paving such as Figure 1 As shown: The large-particle-size hydraulic asphalt mixture in hopper 1 is conveyed into the power extrusion chamber 2, so that the large-particle-size hydraulic asphalt mixture is power extruded into a strip. The width of the strip is 50cm, the thickness of the core wall of the construction layer, and the height is 35cm. The extruded asphalt mixture strip is covered with 50-type diamond mesh on both sides through the chute 3 and continuously spread on the asphalt concrete slab surface 4.

[0040] C. The large-particle-size hydraulic asphalt mixture after paving is compacted to form a large-particle-size hydraulic asphalt concrete layer.

[0041] The compaction of the large-particle-size hydraulic asphalt mixture after paving includes: first, compacting the transition material on both the upstream and downstream sides of the core wall in parallel, and then compacting the large-particle-size hydraulic asphalt mixture after paving.

[0042] When the transition material on both sides of the parallel compaction core wall is being compacted, the remaining transition material with a width of not less than 30cm from both sides of the core wall is not compacted, and then compacted together with the large-particle-size hydraulic asphalt mixture.

[0043] The compaction of the large-diameter hydraulic asphalt mixture after paving includes: initial rolling with static rolling by a double-drum roller; secondary rolling with a combination of vibratory rolling by a double-drum roller and subsequent rolling by a heavy-duty rubber-tired roller; and final rolling with static rolling by a double-drum roller.

[0044] The double steel wheel vibratory roller used for primary, secondary, and final rolling of large-particle-size hydraulic asphalt mixtures is a 3t special vibratory roller.

[0045] The maximum aggregate size of the large-particle-size hydraulic asphalt concrete is 26.5 mm.

[0046] The paving thickness of the large-particle-size hydraulic asphalt mixture is 35cm.

[0047] Appendix Figure 3 The core sample of the hydraulic asphalt concrete with a maximum aggregate particle size of 26.5mm is a preferred mix. It can be clearly seen that the coarse and fine aggregates are randomly and uniformly distributed throughout the sample, which confirms the large-particle-size asphalt concrete paving method of the present invention. The asphalt mixture is uniform and the interlayer bonding quality is good. The walking speed of the asphalt concrete paver can be adjusted according to the supply of asphalt mixture.

[0048] Example 3

[0049] A method for paving large-particle-size hydraulic asphalt concrete with a preferred mix proportion of 31.5 mm as the maximum aggregate size includes the following steps:

[0050] A. Prepare the construction surface of the asphalt concrete core wall before paving; conduct an overall inspection of the construction surface of the asphalt concrete core wall, and for areas with construction defects—such as honeycomb pitting: first, use a nucleus-free density meter to test the density and obtain the porosity of the area. If the porosity is ≤3%, fill the honeycomb pit with hot asphalt; if the porosity is >3%, drill a core sample, and test the core sample porosity in the laboratory. If the core sample porosity is ≤3%, fill the honeycomb pit with hot asphalt; if the porosity is >3%, remove the area and repave with asphalt concrete. Contamination of the construction surface is mainly caused by dust from dam construction or rainwater. Dust can be blown away with an air compressor; rainwater should be washed clean with water and dried. Use an insertion digital thermometer to check the surface temperature of the slab. If the surface temperature is less than 70°C, the slab must be heated before paving. If the surface temperature is between 70-90°C, paving can be done directly. If the surface temperature is greater than 90°C, the surface must be cooled to below 90°C before paving.

[0051] B. Specialized paving equipment should be used to pave large-particle-size hydraulic asphalt mixtures prepared according to the optimized mix proportions.

[0052] The large-particle-size hydraulic asphalt mixture special paving equipment is used for paving such as Figure 1As shown: The large-particle-size hydraulic asphalt mixture in hopper 1 is conveyed into the power extrusion chamber 2, so that the large-particle-size hydraulic asphalt mixture is power extruded into a strip. The width of the strip is 50cm, the thickness of the core wall of the construction layer, and the height is 40cm. The 50-type diamond mesh is laid on both sides of the extruded asphalt mixture strip through the chute 3 and continuously spread on the asphalt concrete slab surface 4.

[0053] C. The large-particle-size hydraulic asphalt mixture after paving is compacted to form a large-particle-size hydraulic asphalt concrete layer.

[0054] The compaction of the large-particle-size hydraulic asphalt mixture after paving includes: first, compacting the transition material on both the upstream and downstream sides of the core wall in parallel, and then compacting the large-particle-size hydraulic asphalt mixture after paving.

[0055] When the transition material on both sides of the parallel compaction core wall is being compacted, the remaining transition material with a width of not less than 30cm from both sides of the core wall is not compacted, and then compacted together with the large-particle-size hydraulic asphalt mixture.

[0056] The compaction of the large-diameter hydraulic asphalt mixture after paving includes: initial rolling with static rolling by a double-drum roller; secondary rolling with a combination of vibratory rolling by a double-drum roller and subsequent rolling by a heavy-duty rubber-tired roller; and final rolling with static rolling by a double-drum roller.

[0057] The double steel wheel vibratory roller used for primary, secondary, and final rolling of large-particle-size hydraulic asphalt mixtures is a 3t special vibratory roller.

[0058] The maximum aggregate size of the large-particle-size hydraulic asphalt concrete is 31.5 mm.

[0059] The paving thickness of the large-particle-size hydraulic asphalt mixture is 40cm.

[0060] Appendix Figure 4 The core sample of large-particle-size hydraulic asphalt concrete with a maximum aggregate size of 31.5mm shows that the coarse and fine aggregates are randomly and uniformly distributed throughout the sample, which confirms the large-particle-size asphalt concrete paving method of the present invention. The asphalt mixture is uniform and the interlayer bonding quality is good. The walking speed of the asphalt concrete paver can be adjusted according to the supply of asphalt mixture.

[0061] The methods and structures not described in detail in the above examples are common knowledge in the industry and will not be described in detail here.

[0062] The above examples are merely illustrative of the present invention and do not constitute a limitation on the scope of protection of the present invention. Any methods that are the same as or similar to the present invention are within the scope of protection of the present invention.

Claims

1. A method for paving large-particle-size hydraulic asphalt concrete, characterized in that, Includes the following steps: A. Preparatory work before paving the asphalt concrete core wall construction site includes: detection and treatment of the non-nuclear density meter in the construction defect area, treatment of the contaminated area of ​​the site, and detection of the site temperature; B. Use specialized paving equipment to pave large-particle-size hydraulic asphalt mixtures prepared according to the optimized mix proportions; The paving process includes: dynamically extruding large-diameter hydraulic asphalt mixture into strips, the width of which is equal to the thickness of the core wall of the construction layer, and the height of which is 35-40cm; laying 50-type diamond mesh on both sides of the dynamically extruded asphalt mixture strips and continuously paving them on the asphalt concrete surface. C. Compact the paved large-particle-size hydraulic asphalt mixture to form a large-particle-size hydraulic asphalt concrete layer. The compaction of the large-particle-size hydraulic asphalt mixture after paving includes: first, compacting the transition material on both the upstream and downstream sides of the core wall in parallel, and then compacting the paved large-particle-size hydraulic asphalt mixture. When the transition material on both sides of the parallel compaction core wall is being compacted, the remaining transition material with a width of 30-50cm from both sides of the core wall is not compacted, and then compacted together with the large-particle-size hydraulic asphalt mixture. The compaction of the large-particle-size hydraulic asphalt mixture after paving includes: initial rolling with static compaction by a double-drum vibratory roller; secondary rolling with a combination of vibration compaction by a double-drum vibratory roller and compaction by a heavy-duty rubber-tired roller; and final rolling with static compaction by a double-drum roller. The double steel wheel vibratory roller is a special vibratory roller with a capacity of not less than 3 tons.

2. The method for paving large-particle-size hydraulic asphalt concrete according to claim 1, characterized in that: The maximum aggregate size range for large-diameter hydraulic asphalt concrete is 26.5–31.5 mm.

3. The method for paving large-particle-size hydraulic asphalt concrete according to claim 2, characterized in that: The paving thickness of large-particle-size hydraulic asphalt mixture is 35-40cm.

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