Low-grade highway hot in-place recycling pavement construction method
By implementing on-site thermal regeneration pavement construction methods on low-grade highways and using integrated equipment for pre-spreading, heating, rolling and mixing, the application difficulties of traditional equipment in low-grade highway construction have been solved, and efficient and environmentally friendly have been achieved pavement regeneration shortens construction period and reduces carbon emissions and traffic impacts.
Patent Information
- Application Number
- CN202411443807.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-16
- Publication Date
- 2024-12-10
AI Technical Summary
Traditional on-site thermal regeneration construction equipment unit train-type equipment is suitable for highways and is difficult to effectively apply in low-grade highway construction. It is limited by conditions such as road width, resulting in fewer applications.
A method of on-site thermal regeneration pavement construction on low-grade highways, including pre-project preparation, testing section construction, formal construction steps, and using integrated on-site thermal regeneration equipment or combined construction methods, by pre-spreading new materials, heating, loosening, and adding Regenerator and fresh asphalt are mixed, spread and compacted to form an efficient pavement regeneration process.
Continuous construction of low-grade highways has been achieved, the construction period has been shortened by more than 50%, the traffic closure time has been reduced, the project cost and carbon emissions have been reduced, and the construction efficiency and environmental protection have been improved.
Smart Images
Figure CN119102158A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of pavement construction, and in particular relates to a method for constructing an in-situ hot regeneration pavement of a low-grade highway. Background Art
[0002] As an efficient and environmentally friendly road maintenance method, in-situ hot regeneration technology is currently widely used in asphalt pavement preventive maintenance projects and can be used to repair various diseases of asphalt pavement surface layers (thickness of about 4 cm). It heats and softens the old asphalt pavement surface layer to a thickness of 4 to 6 cm, then adds an appropriate amount of new asphalt mixture and regeneration agent, remixes and compacts, thereby restoring the performance of the pavement. Compared with traditional milling and paving processes, in-situ hot regeneration technology has technical advantages such as "short recycling process chain, low carbon emissions, high recycling rate of recycled asphalt pavement materials (RAP), and low impact on traffic during the construction process", as well as significant advantages in saving engineering costs.
[0003] However, the traditional on-site hot regeneration construction equipment is mainly large train-type equipment. Large train-type equipment units are long and the width cannot be adjusted. They are generally used in highways (surface thickness is 4 to 5 cm). They are less used in low-grade highway construction due to road width and other conditions. Summary of the invention
[0004] The purpose of the present invention is to provide a method for in-situ hot regeneration pavement construction of low-grade highways in order to solve the above-mentioned problems.
[0005] The technical solution adopted by the present invention is as follows: a method for constructing a low-grade highway in-situ hot regeneration pavement, the method comprising the following steps:
[0006] S1: Carry out preliminary preparation for the project. According to the project volume, expected construction plan and construction period, formulate a detailed construction technical plan, including equipment configuration, construction process, traffic organization plan, prepare new aggregates, asphalt regeneration agent, new asphalt construction materials, and ensure that their quality meets the requirements of the specifications;
[0007] S2: Conduct test section construction with a length of no less than 500m to test equipment performance, determine construction process parameters, verify mixture ratio, and test construction organization and quality control plan;
[0008] S3: Formal construction will be carried out after the test section has passed the inspection. New materials will be pre-spread first. According to the mix ratio design results, new aggregates will be evenly spread using an aggregate spreader.
[0009] S4: Use integrated on-site heat regeneration equipment or combined construction methods to heat the road surface to ensure that the original road surface is fully heated;
[0010] S5: Scarify the road surface according to the design requirements, with uniform scarification depth and slow and gradual changes in scarification depth;
[0011] S6: Add regeneration agent and new asphalt. According to the mix design results, accurately control the amount of regeneration agent and new asphalt added, and then mix the recycled mixture;
[0012] The mix ratio is:
[0013] Regeneration agent addition amount: 4%; new asphalt addition amount: 5%; new aggregate addition amount: 7%; original pavement asphalt content: 5%; original pavement aggregate: 84%;
[0014] S7: Perform paving, and adjust the vibration power during paving according to the type of recycled mixture and the thickness of the recycled layer to increase the initial density of the mixture;
[0015] S8: Compact the road surface. Use vibrating double-wheel rollers or tire rollers that meet the requirements. When using double-wheel rollers, it is advisable to reduce water spraying, and when using tire rollers, do not spray water;
[0016] S9: Perform pavement curing to ensure that the recycled asphalt mixture is fully compacted and stable and reaches the designed strength;
[0017] S10: After the curing is completed, all waste and debris in the work area are removed to ensure environmental hygiene, and the performance of the regenerated pavement is tested, such as compaction, anti-skid performance, and anti-rutting performance, to ensure that it meets the design requirements; then the pavement is opened when the pavement temperature is lower than 50°C, and the entire low-grade highway in-situ hot regeneration pavement construction process is completed.
[0018] In a preferred embodiment, in step S1, during the preliminary preparation process, the on-site hot regeneration construction vehicle and the roller mechanical equipment are checked to ensure that they are in good working condition; during the preliminary preparation process, a traffic control plan needs to be formulated, signs and signs need to be set up, and special personnel need to be arranged for traffic diversion; during the preliminary preparation process, the road surface diseases are pre-treated, including pothole repair and crack treatment, to ensure that the diseases do not affect the quality of the regeneration construction;
[0019] Environmental survey: Investigate the surrounding environment of the construction site and take necessary protective measures to avoid damage to the surrounding environment caused by the construction.
[0020] In a preferred embodiment, in step S2, the test content includes equipment performance test, heating time, heating temperature, construction speed, material addition amount, asphalt dosage, paving temperature, and rolling process.
[0021] In a preferred embodiment, in step S4, the heating width of the original pavement is at least 200 mm wider than the loosening width on each side; at the longitudinal seam overlap, the heating width exceeds the overlapping edge line by 150 mm to 200 mm; heating at the starting point ensures that the temperature reaches the construction requirements, and the heating machine can be operated in a reciprocating multiple times and low-power, long-time heating manner.
[0022] In a preferred embodiment, in step S5, the road surface temperature before scarification is not higher than 185°C for ordinary asphalt pavement and not higher than 200°C for modified asphalt pavement; the road surface temperature after scarification is not lower than 85°C for ordinary asphalt pavement and not lower than 100°C for modified asphalt pavement.
[0023] In a preferred embodiment, in step S5, the loosening process is carried out to minimize aggregate crushing, ensure that there is no interlayer, do not turn up the lower layer of mixture, and ensure that the longitudinal joints are straight; during the construction process, the regeneration depth is checked every 200 meters using the ruler method, and the depth fluctuation range is within ±0.5 cm.
[0024] In a preferred embodiment, in step S6, the asphalt regeneration agent and new asphalt are stored in a storage tank carried on the vehicle, the heating temperature of road petroleum asphalt is controlled at 155°C to 160°C, and the heating temperature of modified asphalt is controlled at 160°C to 165°C; the regeneration agent should be heated according to the product instructions and the heating temperature should be selected to the highest temperature that does not affect the quality of the regeneration agent, so as to improve the fluidity of the regeneration agent and its compatibility with the old asphalt.
[0025] In a preferred embodiment, in step S7, the top surface temperature of the lower supporting layer before paving the raw mixture should not be lower than 100°C. If this temperature cannot be reached during construction, the top surface of the lower supporting layer needs to be additionally heated; the paving speed is controlled at 0.5-2m / min to ensure that the paved mixture is uniform without cracks or segregation; the control of the joints is strengthened during the paving process, and the longitudinal and transverse joints must be flat, dense, well-bonded, without height differences or segregation; the paving temperature of the recycled mixture is controlled at 120°C to 160°C.
[0026] In a preferred embodiment, in step S8, a small vibratory roller or a vibratory tamping plate is used to compact the local area that cannot be compacted by a large machine.
[0027] In a preferred embodiment, in step S9; during the curing period, the ambient temperature is controlled between 10°C and 30°C, the road surface temperature is controlled between 15°C and 25°C, the asphalt temperature is controlled between 30°C and 50°C, the relative humidity is preferably controlled between 60% and 80%, and moisturizing is performed by sprinkling water or covering; during the curing period, compaction tests are performed regularly, and compaction tests are performed by sand injection method, and the test frequency is preferably once a day; the design stability requires that the stability reaches more than 8000 times / mm after 7 days.
[0028] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:
[0029] 1. In the present invention, a certain mass of mineral material is directly pre-spread on the original road surface, and an infrared heating plate is used to heat the pre-spread mineral material and the original road surface together. Then, the milling drum raks and stirs the pre-spread mineral material and the original road surface material together. Since the milling and mixing rotors adopt a spiral structure, the recycled mixture gathers toward the center to form a material barrier, ensuring the lateral uniformity of the recycled mixture. The materials within the length range from the milling drum of the regenerator to the screed of the paver are effectively mixed in the mixing bin to ensure the longitudinal dynamic uniformity of the recycled mixture. Then, the pile of recycled mixture is spread by the tail-end paving equipment with an agitator device, and after rolling, an in-situ hot recycled road surface can be formed.
[0030] 2. In the present invention, the in-situ hot regeneration pavement construction method for low-grade highways can make full use of the original pavement materials and reduce the amount of new materials, thereby reducing the project cost. The in-situ hot regeneration pavement construction method for low-grade highways can be constructed continuously without the need for milling and transportation, with high construction efficiency and short construction period. According to statistics, compared with traditional milling and paving processes, in-situ hot regeneration technology can shorten the construction period by more than 50%. The in-situ hot regeneration pavement construction method for low-grade highways can reduce the traffic closure time during the construction process, has little impact on traffic, and is conducive to ensuring smooth traffic.
[0031] 3. In the present invention, the in-situ hot regeneration pavement construction method for low-grade highways can reduce the mining and processing of new materials, thereby reducing carbon emissions. The in-situ hot regeneration pavement construction method for low-grade highways can reduce the transportation and processing of new materials, thereby saving energy consumption. The in-situ hot regeneration pavement construction method for low-grade highways can reduce the waste generated by milling, thereby reducing environmental pollution, making the entire method more environmentally friendly and scientific. BRIEF DESCRIPTION OF THE DRAWINGS
[0032] Figure 1 This is a construction flow chart of the integrated on-site heat regeneration of the present invention;
[0033] Figure 2 This is a process flow chart of the multiple mixing type in-situ heat regeneration process of the present invention;
[0034] Figure 3 It is a process flow chart of the on-site hot regeneration one-step forming construction technology in the present invention. DETAILED DESCRIPTION
[0035] 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 accompanying drawings and 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.
[0036] Reference Figure 1-3 ,
[0037] Example:
[0038] A method for constructing a low-grade highway hot-in-situ pavement regeneration system, comprising the following steps:
[0039] 1. Construction preparation
[0040] A complete technical construction plan should be formulated before construction, including specific engineering quantities, expected construction plans, construction period, integrated in-situ heat regeneration construction implementation plan, traffic organization plan, etc.
[0041] Before construction, preparations should be made in terms of technology, materials, equipment, personnel, traffic organization, logistics support, etc., and the equipment should be checked to be in good working condition.
[0042] Before construction, a survey of the surrounding environment on site should be conducted, and protective measures should be taken in advance for plant isolation belts, trees, gas stations, etc. that may be affected.
[0043] Before construction, construction information should be released. According to the requirements of JTGH30, highway management departments, and traffic police departments, and based on the length of the work surface, various traffic control signs and billboards should be set up in advance. Dedicated personnel should be on duty to control traffic, and traffic organization and emergency plans should be prepared.
[0044] Before formal construction, a test section of no less than 200m should be constructed to determine the equipment configuration requirements and process parameters. Construction should not be carried out on rainy days, in strong wind conditions, or when the road surface is wet. When the slurry seal, micro-surfacing, ultra-thin overlay, and crushed stone seal pavement regeneration design adopts the in-situ hot regeneration one-step molding construction technology, it is advisable to loosen the above material layers or adjust the gradation by adding new aggregates to meet the quality requirements before regeneration. The main construction machinery and equipment should comply with the provisions of Table 1.
[0045] Table 1 Main construction machinery and equipment
[0046]
[0047] The temperature control heating system should meet the following requirements:
[0048] It should be able to continuously preheat the asphalt pavement within a certain depth range to the specified temperature;
[0049] It should have the function of automatic control of heating capacity and be able to display the heating temperature in time.
[0050] The road surface should be heated evenly, and there should be no phenomenon of burnt asphalt caused by uneven heating.
[0051] It is advisable to have driving speed control and display functions.
[0052] The concentration of asphalt smoke generated during normal operation should meet environmental protection requirements.
[0053] Open flame heating is not recommended.
[0054] The heating scarifying system should meet the following requirements:
[0055] It should have the function of automatic control of heating capacity and be able to display the heating temperature in time.
[0056] It should be possible to hot scarify (or scarify) the old road surface to a predetermined depth and keep the scarification depth stable.
[0057] It should be able to maintain the overall stability of the aggregate-to-asphalt-stone ratio of the old road asphalt mixture without destroying the aggregate gradation.
[0058] The mixing system should meet the following requirements:
[0059] It should have the functions of heating and loosening the road surface, adding asphalt regeneration agent, adding asphalt mixture, and paving.
[0060] The scarifying device should be equipped with an automatic depth control system, and the scarifying depth should not exceed the set value ±3mm.
[0061] The regeneration agent or new asphalt spraying device should be accurately metered, and the spraying metering accuracy should not be less than ±2%.
[0062] Before construction, pavement damage that cannot be repaired by integrated hot-in-place regeneration should be pre-treated and should comply with the following regulations:
[0063] Damaged and loose diseases: If the depth of damaged and loose diseases exceeds the construction depth of integrated in-situ hot regeneration, they should be excavated and repaired.
[0064] Deformation diseases: Depending on the regeneration equipment, when the deformation depth is 20mm to 50mm, loosening should be carried out before regeneration.
[0065] Crack-type diseases: Analyze the causes of crack-type diseases, and the cracks that affect the quality of thermal regeneration projects should be treated.
[0066] The pretreatment of special parts of the original road surface should meet the following requirements:
[0067] Use a scarifier to loosen the expansion joint and manhole cover by 2m to 5m at the rear end and 1m to 2m at the front end along the driving direction, with a depth of 30 to 50mm. New asphalt mixture or recycled asphalt mixture should be used for paving during recycling construction.
[0068] The markings, raised road signs, sealing glue, etc. on the original road surface should be removed.
[0069] Bridge expansion joints should be protected by thermal insulation panels.
[0070] The road surface should be cleaned before construction, and a guide line should be drawn outside the road surface regeneration width. The road surface edge line can also be used as a guide line to ensure that the edge of the regeneration construction is straight and beautiful.
[0071] Before implementing the one-step construction technology of in-situ thermal regeneration, the defects that cannot be eliminated by thermal regeneration should be pre-treated according to the defect investigation results and the applicability of the technology. Different treatment methods can be selected according to the type and area of the defect, such as repair, excavation, grouting, etc. When selecting the treatment method, trenchless methods should be given priority while ensuring the construction quality, so as to minimize the impact of construction on traffic.
[0072] When the height of the rut ridge exceeds a certain limit, its impact on the uniformity of the heating temperature field should be analyzed and verified on site. If the uniformity of the heating temperature field cannot be guaranteed, the ridge should be milled. For expressways and first-class highways, when the height of the rut ridge exceeds 15mm, milling is recommended in advance. For other grades of highways, when the height of the rut ridge exceeds 30mm, milling is recommended in advance.
[0073] General transverse cracks (width not exceeding 2mm) do not need to be treated, but for wider (greater than 2mm) or multiple concentrated transverse cracks with bifurcated or sunken edges, deep pretreatment should be carried out, that is, the upper layer, middle layer, and even the lower layer should be milled in layers in a stepped manner, and anti-cracking stickers should be pasted on them. Then, they should be backfilled and compacted in layers with new asphalt mixture, and the original road elevation should be restored.
[0074] For pits and slurry pumping areas whose depth exceeds the thickness of the surface layer, local excavation and backfilling should be adopted to repair the defects.
[0075] Before construction, take measures such as sweeping and flushing to ensure the cleanliness of the original road surface and remove materials that are contaminated and cannot be recycled.
[0076] If there are hot-melt markings or other debris on the original road surface that may affect the construction quality, they should be cleaned before construction (or removed after heating during construction), and care should be taken to ensure the cleanliness of the original road surface.
[0077] If there are other obstacles on the original road surface that may affect the thermal recycling construction, they should be removed or rearranged before construction.
[0078] Reasonable measures should be taken to protect ancillary facilities on the original road surface that cannot be removed or rearranged, such as using insulation boards to protect bridge expansion joints and road greening.
[0079] 2. Paving of test section
[0080] Before formal construction, a test section should be laid to inspect the production mix ratio, recycling construction technology, process control, construction organization and traffic safety. The length of the test section for the in-situ hot recycling one-step forming construction technology should not be less than 500m.
[0081] Formal construction can only be carried out after the test section construction is qualified. The following work should be completed by paving the test section:
[0082] 1) Check whether the performance of the regeneration equipment meets the construction requirements.
[0083] 2) Determine the construction process and parameters such as heating time, heating temperature and construction speed of the heating equipment.
[0084] 3) Verify the mixture proportion design, check the composition and amount of new materials added and the optimal asphalt dosage.
[0085] 4) Check the feasibility of construction organization and traffic organization plans.
[0086] 5) Verify the feasibility of the quality control plan.
[0087] 3. Construction technology
[0088] 3-1. Pre-spreading of new material
[0089] According to the mix ratio design results, calculate the amount of new material to be spread and use an aggregate spreader to spread it evenly.
[0090] 3-2. Road surface heating
[0091] The one-step construction technology of in-situ heat regeneration can be carried out by using integrated in-situ heat regeneration equipment with various heating principles, or by combining heating units with different heating principles. Pavement heating should meet the following requirements:
[0092] 1) The original road surface must be fully heated. The aggregate should not be damaged during loosening due to insufficient heating temperature, nor should the asphalt be over-aged due to excessive heating temperature.
[0093] 2) The distance between the equipment in the regeneration train should be reduced to minimize heat loss, ensure the quality of regeneration and reduce energy waste.
[0094] 3) The original road surface heating width should be at least 200mm wider than the loosening width on each side.
[0095] 4) At the overlapping part of longitudinal seams, the heating width should exceed the overlapping edge line by 150mm to 200mm.
[0096] 5) Heating at the starting point should ensure that the temperature reaches the construction requirements. The heating machine can be used in a reciprocating and low-power, long-term heating manner.
[0097] 3-3. Loosening of road surface
[0098] The road surface loosening should meet the following requirements:
[0099] 1) The loosening width and depth should be in accordance with the design requirements.
[0100] 2) The scarification depth should be uniform and the scarification depth should change slowly and gradually.
[0101] 3) The loosened surface should have a good roughness.
[0102] 4) The road surface temperature before scarification should not be higher than 185℃ for ordinary asphalt pavement and 200℃ for modified asphalt pavement. The road surface temperature after scarification should not be lower than 85℃ for ordinary asphalt pavement and 100℃ for modified asphalt pavement.
[0103] 5) During the loosening process, the aggregate crushing should be minimized, there should be no interlayer, the lower layer of mixture should not be turned up, and the longitudinal joints should be straight.
[0104] 6) During the construction process, the regeneration depth should be checked every 200 meters (using the ruler method), and the depth fluctuation range should be within ±0.5cm.
[0105] 3-4. Asphalt regeneration agent, new asphalt addition
[0106] Asphalt regeneration agent and new asphalt addition should meet the following requirements:
[0107] 1) The amount of asphalt regeneration agent and new asphalt added should be determined based on the design results of the recycled asphalt mixture ratio.
[0108] 2) Asphalt regeneration agent and new asphalt should be added evenly and precisely controlled.
[0109] 3) During the construction process, the amount of asphalt regeneration agent and new asphalt should be adjusted in time according to the conditions of the regenerated road section.
[0110] 4) Asphalt regeneration agent and new asphalt should be stored in the storage tank carried by the vehicle. The heating temperature of road petroleum asphalt should be controlled at 155℃~160℃, and the heating temperature of modified asphalt should be controlled at 160℃~165℃. The regeneration agent should be heated according to the product instructions and the heating temperature should be selected to the highest temperature that does not affect the quality of the regeneration agent, so as to improve the fluidity of the regeneration agent and its compatibility with the old asphalt.
[0111] 3-5. Mixing
[0112] The recycled mixture should be mixed evenly and the mixing temperature should meet the requirements of Table 2.
[0113] Table 2 Temperature control during the integrated construction process of integrated in-situ heat regeneration
[0114]
[0115] 3-6. Paving
[0116] 1) The top surface temperature of the lower bearing layer before paving the recycled mixture should not be lower than 100 (50) °C. If this temperature cannot be reached during the construction process, the top surface of the lower bearing layer needs to be additionally heated.
[0117] 2) The paving speed should be coordinated with the travel speed of the heating equipment. Generally speaking, the travel speed of a large thermal regeneration unit is 1.5 to 3 m. Since the on-site thermal regeneration integrated molding construction equipment is short, it is recommended that the travel speed be controlled at 0.5-2 m / min to ensure that the paving mixture is uniform without cracks, segregation, etc.
[0118] 3) According to the type of recycled mixture and the thickness of the recycled layer, adjust the vibration power during paving to increase the initial density of the mixture.
[0119] 4) During the paving process, the control of the joints should be strengthened. The longitudinal and transverse joints must be flat, dense, well-bonded, without height differences and segregation.
[0120] 5) The paving temperature of the recycled mixture should be controlled between 120℃ and 160℃.
[0121] 3-7 Compaction
[0122] 1) Rolling should be carried out using compaction equipment such as vibratory double-wheel rollers and tire rollers that meet the requirements of Table 1.
[0123] 2) The compaction process determined in the test section should be used.
[0124] 3) Rolling should be carried out closely after paving. When using a double-wheel roller, it is advisable to reduce water spraying, and when using a tire roller, it is not advisable to spray water.
[0125] 4) For local areas that cannot be compacted by large machines, a small vibratory roller or vibrating tamping plate should be used for compaction.
[0126] 5) If conditions permit, warm mix technology can be used to reduce the construction temperature.
[0127] 3-8. Health preservation and open traffic
[0128] 1) The road surface temperature should be lower than 50℃ when opening to traffic. Before opening to traffic, vehicles are strictly prohibited from passing on the formed road surface.
[0129] 2) Before removing the signs, all waste and debris in the work area should be cleared away, and waste and garbage should not be discarded on the slopes, ditches and median strips.
[0130] 3) The opening of recycled pavement to traffic and other matters shall comply with the relevant provisions of the current "Technical Specifications for Highway Asphalt Pavement Construction" (JTGF40) on hot mix asphalt pavement.
[0131] From the above, we can know that:
[0132] In the present invention, a certain mass of mineral material is directly pre-spread on the original road surface, and an infrared heating plate is used to heat the pre-spread mineral material and the original road surface together. Then, the milling drum raks and stirs the pre-spread mineral material and the original road surface material together. Since the milling and mixing rotors adopt a spiral structure, the recycled mixture gathers toward the center to form a material barrier, ensuring the lateral uniformity of the recycled mixture. The materials within the length range from the milling drum of the regenerator to the screed of the paver are effectively mixed in the mixing bin to ensure the longitudinal dynamic uniformity of the recycled mixture. Then, the pile of recycled mixture is spread by the tail-end paving equipment with a auger device, and after rolling, an in-situ hot recycled road surface can be formed.
[0133] In the present invention, the in-situ hot regeneration pavement construction method for low-grade highways can make full use of the original pavement materials, reduce the amount of new materials, and thus reduce the project cost. The in-situ hot regeneration pavement construction method for low-grade highways can be constructed continuously without milling and transportation, with high construction efficiency and short construction period. According to statistics, compared with traditional milling and paving processes, the in-situ hot regeneration technology can shorten the construction period by more than 50%. The in-situ hot regeneration pavement construction method for low-grade highways can reduce the traffic closure time during the construction process, has little impact on traffic, and is conducive to ensuring smooth traffic.
[0134] In the present invention, the in-situ hot regeneration pavement construction method for low-grade highways can reduce the mining and processing of new materials, thereby reducing carbon emissions. The in-situ hot regeneration pavement construction method for low-grade highways can reduce the transportation and processing of new materials, thereby saving energy consumption. The in-situ hot regeneration pavement construction method for low-grade highways can reduce the waste generated by milling, thereby reducing environmental pollution, making the entire method more environmentally friendly and scientific.
[0135] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.
[0136] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for hot-in-situ regeneration of low-grade highway pavement construction, characterized in that: The method comprises the following steps: S1: Carry out preliminary preparation for the project. According to the project volume, expected construction plan and construction period, formulate a detailed construction technical plan, including equipment configuration, construction process, traffic organization plan, prepare new aggregates, asphalt regeneration agent, new asphalt construction materials, and ensure that their quality meets the requirements of the specifications; S2: Conduct test section construction with a length of no less than 500m to test equipment performance, determine construction process parameters, verify mixture ratio, and test construction organization and quality control plan; S3: Formal construction will be carried out after the test section has passed the inspection. New materials will be pre-spread first. According to the mix ratio design results, new aggregates will be evenly spread using an aggregate spreader. S4: Use integrated on-site heat regeneration equipment or combined construction methods to heat the road surface to ensure that the original road surface is fully heated; S5: Scarify the road surface according to the design requirements, with uniform scarification depth and slow and gradual changes in scarification depth; S6: Add regeneration agent and new asphalt. According to the mix design results, accurately control the amount of regeneration agent and new asphalt added, and then mix the recycled mixture; The mix ratio is: Regeneration agent addition amount: 4%; new asphalt addition amount: 5%; new aggregate addition amount: 7%; original pavement asphalt content: 5%; original pavement aggregate: 84%; S7: Perform paving, and adjust the vibration power during paving according to the type of recycled mixture and the thickness of the recycled layer to increase the initial density of the mixture; S8: Compact the road surface. Use vibrating double-wheel rollers or tire rollers that meet the requirements. When using double-wheel rollers, it is advisable to reduce water spraying, and when using tire rollers, do not spray water; S9: Perform pavement curing to ensure that the recycled asphalt mixture is fully compacted and stable and reaches the designed strength; S10: After the curing is completed, all waste and debris in the work area are removed to ensure environmental hygiene, and the performance of the regenerated pavement is tested, such as compaction, anti-skid performance, and anti-rutting performance, to ensure that it meets the design requirements; then the pavement is opened when the pavement temperature is lower than 50°C, and the entire low-grade highway in-situ hot regeneration pavement construction process is completed.
2. A method for hot-in-situ regeneration of low-grade highway pavement construction as claimed in claim 1, characterized in that: In the step S1, during the preliminary preparation, the hot-in-place regeneration construction vehicles and rollers are checked to ensure that they are in good working condition; during the preliminary preparation, a traffic control plan needs to be formulated, signs and signs need to be set up, and special personnel need to be arranged for traffic diversion; during the preliminary preparation, road surface diseases are pre-treated, including pothole repair and crack treatment, to ensure that the diseases do not affect the quality of the regeneration construction; Environmental survey: Investigate the surrounding environment of the construction site and take necessary protective measures to avoid damage to the surrounding environment caused by the construction.
3. A method for hot-in-situ regeneration of low-grade highway pavement construction as claimed in claim 1, characterized in that: In step S2, the test contents include equipment performance test, heating time, heating temperature, construction speed, material addition amount, asphalt dosage, paving temperature, and rolling process.
4. A method for hot-in-situ regeneration of low-grade highway pavement construction as claimed in claim 1, characterized in that: In step S4, the heating width of the original pavement is at least 200mm wider than the loosening width on each side; at the longitudinal seam overlap, the heating width exceeds the overlap edge line by 150mm to 200mm; heating at the starting point ensures that the temperature reaches the construction requirements, and the heating machine can be carried out by reciprocating multiple times and low-power, long-term heating.
5. A method for hot-in-situ regeneration of low-grade highway pavement construction as claimed in claim 1, characterized in that: In step S5, the road surface temperature before scarification is not higher than 185°C for ordinary asphalt pavement and not higher than 200°C for modified asphalt pavement; the road surface temperature after scarification is not lower than 85°C for ordinary asphalt pavement and not lower than 100°C for modified asphalt pavement.
6. A method for hot-in-situ regeneration of low-grade highway pavement construction as claimed in claim 1, characterized in that: In step S5, during the loosening process, aggregate crushing is minimized, interlayer is ensured, lower mixed material is not turned up, and longitudinal joints are straight; during the construction process, the regeneration depth is checked every 200 meters using the ruler method, and the depth fluctuation range is within ±0.5 cm.
7. A method for hot-in-situ regeneration of low-grade highway pavement construction as claimed in claim 1, characterized in that: In step S6, the asphalt regeneration agent and new asphalt are stored in a storage tank carried on the vehicle, the heating temperature of road petroleum asphalt is controlled at 155°C to 160°C, and the heating temperature of modified asphalt is controlled at 160°C to 165°C; the regeneration agent should be heated according to the product instructions and the heating temperature should be selected to the highest temperature that does not affect the quality of the regeneration agent, so as to improve the fluidity of the regeneration agent and its compatibility with the old asphalt.
8. A method for hot-in-situ regeneration of low-grade highway pavement construction as claimed in claim 1, characterized in that: In step S7, the top surface temperature of the lower supporting layer before paving the raw mixture should not be lower than 100°C. If this temperature cannot be reached during the construction process, the top surface of the lower supporting layer should be additionally heated; the paving speed is controlled at 0.5-2m / min to ensure that the paved mixture is uniform without cracks or segregation; the control of the joints is strengthened during the paving process, and the longitudinal and transverse joints must be flat, dense, well-bonded, without height differences or segregation; the paving temperature of the recycled mixture is controlled at 120°C to 160°C.
9. A method for hot-in-situ regeneration of low-grade highway pavement construction as claimed in claim 1, characterized in that: In step S8, a small vibratory roller or a vibratory tamping plate is used to compact the local parts that cannot be compacted by large machines.
10. A low-grade highway in-situ hot regeneration pavement construction method as claimed in claim 1, characterized in that: In the step S9; during the curing period, the ambient temperature is controlled between 10°C and 30°C, the road surface temperature is controlled between 15°C and 25°C, the asphalt temperature is controlled between 30°C and 50°C, the relative humidity is preferably controlled between 60% and 80%, and moisture is retained by sprinkling or covering; during the curing period, compaction tests are performed regularly, and compaction tests are performed by the sand filling method, and the test frequency is preferably once a day; the design stability requirement is that the stability reaches more than 8000 times / mm after 7 days.